ARTICLE | doi:10.20944/preprints202312.0022.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aedes aegypti; immature stage; traits; fecundity; longevity; body size; Burkina Faso
Online: 1 December 2023 (05:15:07 CET)
Aedes aegypti is the main vector of various arboviruses including dengue, yellow fever, Zika and chikungunya virus. This mosquito species originated in Africa but has a wide range of distribution, colonising various ecological zones. The transmission dynamics of arboviruses depends on environmental factors, but also on mosquito life history traits including development time, fecundity, and longevity. The objective of the current study was to assess the Aedes aegypti immature development time, adult longevity, fecundity and body variation from different sampling localities. Aedes aegypti mosquitoes were collected as eggs from different geographical zones and cohorts of mosquitoes were reared in standardized laboratory conditions to assess the life history traits parameters. Emerged adults were discriminated into morphotypes according to the density of white scales on the first abdominal tergite. The means of fecundity, longevity, development time and body size were assessed, and linear models were fitted to the traits parameters to assess the effects of other covariables. Average Aedes aegypti development time was estimated to 7.35 days; 7.40 days; 6.98 days and 7.40 days respectively for Dori, 1200 logements, Bobo-Dioulasso and Toudweogo. The fecundity did not vary across study sites and was not associated with the body size. The longevity varied according to the study sites with the mosquitoes from Bobo-Dioulasso having the longest longevity while the shortest longevity was found at Dori. Fed mosquitoes had longer longevity compared to unfed ones. Morphological identification showed that Aedes aegypti aegypti-like mosquitoes were more predominant than Aedes aegypti formosus-like mosquitoes in all the study sites, suggesting the predominance of Aedes aegypti in the urban environment. Our data suggest that the geographical origin of Aedes aegypti mosquitoes in Burkina Faso has a little effect on its life history traits.
ARTICLE | doi:10.20944/preprints202311.1920.v1
Subject: Biology And Life Sciences, Insect Science Keywords: active learning; development; phenology; pollinator; climate change; incubator; survival rate; pupation time; butterfly
Online: 30 November 2023 (04:10:46 CET)
Temperature increases mediated through climate change threaten the survival of species. It is of foremost importance to engage citizens and future generations in understanding the mechanisms through which temperatures imposes its affect. For educators though this is not straight forward as tools for examined the impact of temperature over the lifetime of an animal are prohibitively expensive. At the same time environmental educators need guidance on the appropriate study systems to use with a balance between the species having an obvious response and ensuring the outcomes are ethical and sustainable. In our study, we created and tested a cost-effective experiment meant to be used for environmental education purposes. More specifically, we tested the sensitivity of the Painted lady butterfly Vanessa cardui to temperature variations using a homemade incubator. We describe the design of this experiment and report findings on survival rate, morphological variations, pupation time, and wingspan of adults across a range of biologically relevant temperatures. The information provided give educators options for testing a variety of hypotheses with regards to the impacts of temperature using an affordable and flexible set-up. Furthermore, the findings can be used by students to develop an understanding of the ramifications of the butterflies responses in an ecological context.
ARTICLE | doi:10.20944/preprints202311.1845.v1
Subject: Biology And Life Sciences, Insect Science Keywords: aphids; shrubs; gas exchange; photosynthetic pigments; CHN partition
Online: 29 November 2023 (11:05:44 CET)
Shrubs are a significant component of urban vegetation residing in parks, but they experience various influences of biotic and abiotic agents, among which aphids play an important role. In this work, the effect of aphid colonization on three shrub species in urban environment was examined. Fourteen parameters have been analyzed, describing photosynthetic pigment content and gas exchange to carbon, nitrogen, and hydrogen partition. While no significant effect of colonization was found on photosynthetic pigment parameters, the effect was significant on gas exchange parameters. The strongest effect aphid colonization achieved on nitrogen partition and C/N ratio, parameters that could be suggested in further similar studies. All parameters were classified in two groups according to principal component analysis, suggesting correlation between nitrogen and carbon content, C/N ratio, measured gas exchange parameters and chlorophyll a content. The ratio between net photosynthesis and dark respiration (A/K) was in the second group, suggesting that this parameter provide additional information on the effect of aphid colonization, and deserve special attention in further studies. There were differences in reaction of examined shrub species, where the strongest reaction by gross primary productivity (GPP) achieved Hybiscus syriacus, and by nitrogen partition and C/N ratio Spirea trilobata and Cydonia japonica.
ARTICLE | doi:10.20944/preprints202311.1687.v1
Subject: Biology And Life Sciences, Insect Science Keywords: honey bee; Apis mellifera; diets; gut microbiome; lactobacillus; rhizobiaceae; vitellogenin
Online: 27 November 2023 (09:15:43 CET)
Honey bee (Apis mellifera) health is crucial for honey bee products, and effective pollination and is closely associated with gut bacteria. Various factors such as reduced habitat, temperature, disease, and diet affect the health of honey bees, by disturbing the homeostasis of the gut microbiota. In this study, high-throughput 16S rRNA gene sequencing was used to analyze the gut microbiota of Apis mellifera subjected to seven different diets. The identified microbiota in the Apis mellifera gut from all the diets consisted of Lactobacillus (62%), followed by Rhizobiaceae (21%), Snodgrassella (4%), and Erwiniaceae (4%) among other 33 genera. Based on diet types, Lactobacillus a lactic acid bacteria (LAB), dominates the microbiota with the highest relative abundance in AIGT+SAC (91%), AIGT+Soytide (88%), and AIGT+Apple juice (69%) diet groups. Bifidobacterium and Commensalibacter appeared as the second most abundant genera in AIGT+SAC and AIGT+Soytide diet groups, respectively. These bacteria are important markers for honey bee health. Considering the importance of these diets in shaping their host microbiome into a healthy status. Individual honey bee health (IHH) was observed to validate the quality and correlation between the microbiota and honey bee health. The results were consistent, indicating that Apis mellifera fed on AIGT+Soytide and AIGT+SAC diet showed the highest health expression level of vitellogenin. The group with 60%Syrup possessing Rhizobiaceae as the dominant taxa showed poor health status. This finding paved the way for establishing a link between gut microbiota and IHH under different diets.
ARTICLE | doi:10.20944/preprints202311.1491.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Juvenile hormone; Methoprene-tolerant; diterpene; Juvenile hormone disruptor; Curcuminoids; Demethoxycurcumin; Bisdemethoxycurcumin
Online: 23 November 2023 (08:44:33 CET)
Juvenile hormones (JH) play crucial roles in insect development, reproduction, and other physi-ological functions. Because JH is specific to arthropods, including insects, it has long been stud-ied for use in pest control. Accordingly, this study aimed to identify the substances that act as JH disruptors from edible plants. Curcuminoids generally exhibit a wide range of biological ac-tivities, such as antioxidant, anti-inflammatory, antibacterial, and insecticidal properties, and they exhibit insect growth inhibitory effects. Demethoxycurcumin and bisdemethoxycurcumin, two curcuminoids from the turmeric plant Curcuma longa L. inhibit the formation of a metho-prene-tolerant (Met)–Taiman (Tai) heterodimer complex as shown through in vitro yeast two-hybrid assays. An artificial diet containing 1% (w/v) demethoxycurcumin or bisdemethox-ycurcumin reduced the number of larvae, leading to no pupal development. Building on our re-sults regarding curcuminoids, researchers can use our study as a reference to develop eco-friendly pesticides.
ARTICLE | doi:10.20944/preprints202311.1121.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Nurse bees; DWV-A; OBPs; synaptic genes; olfactory responses
Online: 17 November 2023 (08:55:52 CET)
Insect behavior is coordinated mainly by smell, through the diverse odor-binding proteins (OBP) that allow them to identify and recognize their environment. Sensory information collected through smell is then analyzed and interpreted in the brain, allowing for correct insect functioning. The behavior of honey bees (Apis mellifera L.) can be affected by different pathogens, such as deformed wing virus (DWV). In particular, DWV variant A (DWV-A) is capable of altering olfactory sensitivity, reducing the gene expression of different OBPs, including those associated with nursing behavior. DWV is also capable of replicating itself in the sensory lobes of the brain, further compromising the processing of sensory information. This study evaluated the behavioral response of nurse honey bees exposed to a pheromone compound and the alterations in the gene expression of pre- and post-synaptic neuronal genes neuroxins-1 and neurogilin-1 in the bee heads and OBP proteins in antennae of nurse bees inoculated with DWV-A. The behavioral response of nurse bees exposed to the larval pheromone compounds benzyl alcohol was analyzed using a Y-tube olfactometer. The viral load, gene expression of OBP5 and OBP11 in antennae and the neuroxins-1 and neurogilin-1 in the bee heads were analyzed by qPCR. High viral loads significantly reduced the ability of 10- and 15-day-old nurse honey bees to choose the correct pheromone compound. Also, the gene expression of OBP5, OBP11, neuroxin-1 and neurogilin-1 in nurse honey bees decreased when they were highly infected with DWV-A. These results suggest that a DWV-A infection can disturb information processing and cause nurse honey bees to reduce their activity inside the hive, altering internal cohesion.
ARTICLE | doi:10.20944/preprints202311.0771.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Long-lasting insecticidal net; median function survival; survivoship; attrition; fabric integrity; Tanzania
Online: 13 November 2023 (10:17:43 CET)
Long-lasting insecticidal nets (LLINs) have been the main contributor to the reduction of malaria in the past two decades in sub-Saharan Africa. Development of pyrethroid insecticide resistance threatens the effectiveness of these LLINs, especially when nets become holed and the insecticide decays. Three classes of dual active ingredient (AI) LLINs, have been assessed for their physical durability as follows: 1) Royal Guard®, combining pyriproxyfen, which is known to disrupt female reproduction and fertility of eggs, and a pyrethroid alpha-cypermethrin; 2) Interceptor® G2, two adulticides with differing modes of action; chlorfenapyr and alpha-cypermethrin; 3) OlysetTM Plus incorporates permethrin (pyrethroid) and a synergist, piperonyl butoxide, to enhance the potency of pyrethroid insecticides; all nets were compared to standard pyrethroid only net (Interceptor®). About 40,000 nets of each type were distributed in February 2019 to different villages in Misungwi. A total of 3072 LLINs were followed at 6, 12, 24, 30 and 36 months to assess survivorship and fabric integrity in a community setting. The median functional survival were less than three years with Interceptor®, Interceptor® G2 and Royal Guard® having 1.9 year each and 0.9 years for OlysetTM Plus . After 36 months, 90% of OlysetTM Plus and Royal Guard® and 87% of Interceptor® G2 were no longer present (thrown away) in the households due to wear and tear, compared to 79% for standard Interceptor®. Short life spans of all assessed LLINs were driven by material of the net, rather than social economic status and housing material. All dual AI LLINs have a poor textile durability with OlysetTM Plus being the worst of the three.
ARTICLE | doi:10.20944/preprints202311.0462.v1
Subject: Biology And Life Sciences, Insect Science Keywords: novel food; risk perception; valorization; food safety; insects
Online: 8 November 2023 (03:33:18 CET)
Edible insects can diversify diets, improve livelihoods, contribute to food and nutrition security, and have a smaller ecological impact. European Union has categorized insects as novel food, and recently, in 2021 and 2022, two species: Tenebrio molitor and Acheta domesticus have been authorized for commercialization. Acceptance and perception of food risk derived from insect consumption vary depending on factors impacting insect consumption acceptability, including neophobic tendencies, gender differences, familiarity, and gastronomic perceptions. The aim of this work was to evaluate the perception and acceptance of edible insects by exploring those factors. The study was carried out on higher education students from Universities from Valencia (Spain). Students recognize insects for their high nutritional value, particularly protein content, and have varying knowledge levels about specific nutritional components. In terms of labeling and marketing, removing health and sustainability benefits from packaging can improve consumer responses. Most respondents prefer clear labeling of insect derivatives, quality certification seals, and complete information about insect content. Students consider marketing and knowledge as significant influencers of insect consumption. In summary, the text highlights the multifaceted nature of insect consumption acceptability. These insights offer valuable perspectives on insect consumption dynamics.
ARTICLE | doi:10.20944/preprints202311.0363.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Colias; DNA barcoding; Lepidoptera; molecular taxonomy; PCR screening; Wolbachia
Online: 6 November 2023 (14:54:07 CET)
The genus Colias Fabricius, 1807 includes numerous taxa and forms with uncertain status and taxonomic position. Among such taxa are Colias mongola Alphéraky, 1897 and Colias tamerlana Staudinger, 1897, interpreted in the literature either as conspecific forms, as subspecies of different but morphologically somewhat similar Colias species, or as distinct species-level taxa. Based on mitochondrial and nuclear DNA markers, we reconstruct a phylogeographic pattern of the taxa in question. We recover and include in our analysis DNA barcodes of the century-old type specimens, the lectotype of C. tamerlana deposited in the Natural History Museum (Museum für Naturkunde), Berlin, Germany (ZMHU), the paralectotype of C. tamerlana and the lectoptype of C. mongola deposited in the Zoological Institute, Russian Academy of Sciences, Saint-Petersburg, Russia (ZISP). Our analysis grouped all specimens within four (HP_I-HP-IV) deeply divergent but geographically poorly structured clades which did not support nonconspecifity of C. mongola–C. tamerlana. We also show that all studied females of the widely distributed haplogroup HP_II were infected with a single Wolbachia strain belonging to the supergroup B, while the males of this haplogroup, as well as all other investigated specimens, were not infected. Our data underline the relevance of large-scale sampling dataset analysis and the need of testing for Wolbachia infection to avoid erroneous phylogenetic reconstructions and species misidentification.
ARTICLE | doi:10.20944/preprints202311.0360.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Bombyx mori; Bmtret1; BmNPV resistance; Bioinformatics analysis; Viral replication
Online: 6 November 2023 (14:21:46 CET)
Trehalose is a non-reducing disaccharide and participates in physiological activities such as or-gan formation, energy metabolism, and stress resistance of insects. In the present study, phylo-genetic analysis divided 21 Bmtret1 orthologs into three clades. These genes are equally distrib-uted on the nine chromosomes. Cis-elements in the promoter regions of Bmtret1s indicated the possible function of Bmtret1s in response to hormones and environmental stimulus. The qPCR analysis showed the significantly different expression levels of Bmtret1s in different tissues and organs, indicating possible functional divergence. In addition, most Bmtret1s showed disturbed expression levels in response to BmNPV stresses. Our results provide a foundation for further functional dissection of Tret1s in Bombyx mori and implicate them as potential regulators for an-tiviral responses.
ARTICLE | doi:10.20944/preprints202311.0305.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Insect; cockroach; locomotor activity; insecticide; neonicotinoid; acetamiprid
Online: 6 November 2023 (07:54:11 CET)
Toxicological studies have shown that the cockroach Periplaneta americana is a classical model for studying the mode of action of commonly used insecticides. In a previous study, we demonstrated that thiamethoxam and clothianidin decreased locomotor activity and decreased the locomotor activity in an open-field-like apparatus. Here, we tested the effect of the neonicotinoid acetamiprid when applied orally, topically, or injected into the haemolymph. We found that acetamiprid decreased locomotor activity in the open-field-like apparatus. When treated with acetamiprid, a strong alteration in locomotor activity was observed 1 h, 24 h and 48 h after haemolymph and topical applications. Oral application of acetamiprid demonstrated that it impaired locomotor activity at 24 h and 48 h. A comparison of the present data with our previously published results showed that neonicotinoids were more active when injected into the haemolymph compared to oral and topical applications. These findings increased our understanding of the effect of neonicotinoid insecticides on insect locomotor activity, and demonstrated that the cyano-substituted neonicotinoid, acetamiprid, was able to alter cockroach locomotor activity.
ARTICLE | doi:10.20944/preprints202311.0287.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Diacheila polita; Elaphrus lapponicus; ground beetles; forest tundra; fossil; Hokkaido; Last Glacial period; paleoenvironment
Online: 6 November 2023 (07:34:09 CET)
Fossil body parts of the two cold-adapted ground beetle species, Elaphrus lapponicus and Diacheila polita, were found from a deposit dated in the late Last Glacial period in Hokkaido, Japan. The paleoenvironment was estimated from their modern distribution and habitat, along with the results of the paleobotanical studies at the site. The temperature was at least 6 degrees lower than modern in summer, and the area around the site was mostly covered with forest tundra, which can currently be seen in areas further north of Hokkaido.
ARTICLE | doi:10.20944/preprints202311.0222.v1
Subject: Biology And Life Sciences, Insect Science Keywords: biological control; Erythrina sandwicensis; Eulophidae; Eurytomidae; Hawaii; wiliwili
Online: 3 November 2023 (07:58:26 CET)
Eurytoma erythrinae Gates & Delvare (Hymenoptera: Eurytomidae), is an important biological control agent of the erythrina gall wasp (EGW), Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae), an invasive species native likely originating in eastern Africa, that is a threat to Erythrina trees in Hawaii and worldwide. Thousands of Erythrina trees in Hawaii succumbed to EGW since 2005 and died within few years of infestation. The endemic wiliwili tree, Erythrina sandwicensis, an important component of Hawaii’s dry forests, and one of few deciduous native trees were severely impacted by this wasp. Early during the invasion by EGW it became evident that the endemic species may be driven to extinction, and exploration programs for natural enemies of the EGW started in December 2005. East Africa was selected as the start point for natural enemy exploration owing to high native Erythina species richness. Several gall formers were found in Tanzania and a putative color variant type of Q. erythrinae was detected in association with three ectoparasitoids. During January 2006, the dominant parasitoid of this gall former was introduced to Hawaii and described as the new species, E. erythrinae. It was found in Ghana, and South Africa attacking other gall wasp species on Erythrina. Eurytoma erythrinae was a voracious ectoparasitoid feeding as a predator on 1 – 5 adjacent EGW immatures to complete its development. Host specificity studies that included seven non-target gall-forming species showed no evidence of attraction or parasitism by this parasitoid. Mean ± SEM longevity of host deprived females (40.4 ± 2.2 days) was significantly higher than males (20.5 ± 1.1 days). Host feeding enhanced longevity of ovipositing female (51.3 ± 1.5 days). Female’s peak fecundity (105 – 239 offspring /female), host feeding biology, short life cycle (18.4 ± 0.1 days), and synchronization with the host, were additional desirable attributes of E. erythrinae. The parasitoid was approved for field release in Hawaii in November 2008. A total of 3998 wasps were distributed on six Hawaiian Islands, with establishment in less than a year. Impacts on high density infestations of EGW were sufficient to prevent tree deaths. Limited rates of parasitism on low density galled leaves, flowers, and seedpods necessitated the consideration for releasing a second parasitoid, Aprostocetus nitens (Hymenoptera: Eulophidae). We report on the reproductive characteristics, and host specificity of E. erythinae that could be of importance for classical biocontrol programs in areas with EGW problem.
ARTICLE | doi:10.20944/preprints202310.2074.v1
Subject: Biology And Life Sciences, Insect Science Keywords: nymphal stages; adult females; morphology; spoil heaps; SEM
Online: 31 October 2023 (10:35:40 CET)
The morphological characters of adult females of Trionymus aberrans Goux 1938 that had been collected in post-industrial wastelands and other habitats in Poland and other countries were studied. A distinctive morphological variability was observed in the specimens that had been collected from post-industrial wastelands in Poland. SEM photos of the morphological characters of T. aberrans are provided. The occurrence of unusual pores with four loculi was demonstrated for the first time in a species of the family Pseudococcidae. The importance of introducing additional morphological characters into the species description is discussed. New data on the frequency and host preference of T. aberrans are also provided. Our research is the first long-time study on scale insect species in post-industrial wastelands. The second-instar nymph of T. aberrans is described. The presence of translucent pores on the hind coxae in second-instar nymph was revealed.
ARTICLE | doi:10.20944/preprints202310.2070.v1
Subject: Biology And Life Sciences, Insect Science Keywords: egg activation; mechanical pressure; Sirex noctilio; Hymenoptera; Amylostereum areolatum, artificial diet, rearing, larval development, pine, genetic pest management
Online: 31 October 2023 (10:31:16 CET)
Egg activation is a cellular transition of an arrested mature oocyte into a developing embryo through a coordinated series of events. Previous studies in Hymenoptera have indicated that mechanical pressure can induce egg activation. In this study, we developed the first egg activation protocol for the haplodiploid insect pest, Sirex noctilio (Hymenoptera: Siricidae), from two climatically different regions in South Africa. In addition, activated eggs were exposed to three treatments involving water, pine sawdust, and the fungal symbiont of S. noctilio, Amylostereum areolatum (Russulales: Amylostereaceae), to confirm the hypothesised prerequisite of the symbiotic fungus for egg development. A rearing protocol was developed for emerged first instar larvae using a modified Anoplophora glabripennis (Coleoptera: Cerambycidae) artificial diet. A significant difference between mean survival rates of activated eggs from the two different regions was observed. Amylostereum areolatum was shown to be unnecessary for egg survival and adversely affected egg eclosion. Maximum larval survival duration on the artificial diet was 92 days. The egg activation and rearing protocol developed in this study enables opportunities for research on the physiology, ecology, symbioses, and genetics of S. noctilio, which can be exploited for new genetic pest management strategies.
ARTICLE | doi:10.20944/preprints202310.1928.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Brachymeria; Eupelmus; host-parasite interaction; local adaptation; Platygasteridae; Telenomus remus; Stenobracon
Online: 31 October 2023 (06:43:45 CET)
Spodopotera frugiperda is a worldwide invasive pest that has caused major economic damage. According to classical biological control theory, natural enemies that can control invasive pests come from the area of origin as the pests that have gone through coadaptation processes. Our study, however, suggests that new associations between S. frugiperda and local natural enemies offer insights into the possibilities of biological control using local parasitoids. The research was conducted through a rapid survey in Yogyakarta, Indonesia, covering four districts in Sleman, Bantul, Gunung Kidul, and Kulon Progo from September 2019 to June 2022. The results showed a stable increase of parasitoid species richness found yearly, with 15 parasitoid species associated with S. frugiperda. Four egg parasitoids, eight larval parasitoids, and three pupal parasitoids were found to be associated with S. frugiperda for three years after it was first discovered in Indonesia. Telenomus remus is the most dominant parasitoid, with a higher abundance and parasitism rate than other parasitoids. A new association was found between S. frugiperda and twelve parasitoid species, consisting of three egg parasitoids (Telenomus remus, Hymenoptera sp.1 and Hymenoptera sp.2), six larval parasitoids (Apanteles sp., Microplitis sp., Campoletis sp., Coccygidium sp., Eupelmus sp., and Stenobracon sp.), and three pupal parasitoids (Brachymeria lasus, B. femorata, and Charops sp.). This study also reported the first findings of the association of S. frugiperda with the larval parasitoid Megaselia scalaris in Indonesia. The result suggests the revisit of classical biological control and that local natural enemies can foster quick adaptation to invasive pests.
ARTICLE | doi:10.20944/preprints202310.1952.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aedes aegypti; sticky trap; lure; entomological surveillance.
Online: 30 October 2023 (15:12:43 CET)
Surveillance is the systematic data collection, analysis, and interpretation essential to planning and implementing control activities. The lack of success in control and surveillance elsewhere for the Ae. aegypti mosquito demands developing new accessible and effective strategies. This work aimed to develop and evaluate an adhesive and lure trap for household indoor and outdoor surveillance of Ae. aegypti. Based on a bibliographic review, four compounds with significant attraction percentages for Ae. aegypti were considered. Our more effective blend was determined by preliminary bioassays using the high-throughput screening system (HITSS) and 90 × 90 cm mosquito cages. We designed a low-cost, pyramid-shaped, sticky cardboard trap to incorporate the selected blend. Semi-field 2 x 2 m cages and field tests were conducted to evaluate its effectiveness through mosquito capture percentages. In laboratory tests, blend number 2 presented an attraction percentage of 47.5 ± 4.8%; while in semi-field cages, a 4-inch, 110-v powered fan was used to disperse the attractants, then a similar capture percentage of 43.2 ± 4.0 % was recorded. Field evaluation of the at-house indoor environment and comparing it with the golden standard BG-Sentinel trap recorded interesting results, i.e., an average of our prototype 6.0 ± 1.5 trapped mosquitoes versus 10.0 ± 2.6. In most Latin American countries, there is a lack of formal and accessible strategies for monitoring adult populations of Ae. aegypti, therefore, must develop tools that reinforce entomological surveillance methods.
REVIEW | doi:10.20944/preprints202310.1544.v1
Subject: Biology And Life Sciences, Insect Science Keywords: natural selection, genetic variation, population structure, Varroa resistance, behaviour
Online: 25 October 2023 (05:18:32 CEST)
This article explains how resistance alleles have become rare or have disappeared from honey bee populations in Europe (and probably also in North America). Honeybees have the highest recombination frequency of all animals, indicating that pathogenic bacteria, viruses, fungi and microsporidia are an important source of selection. To respond to new virulent strains of pathogens, honeybees need to have access to rare alleles that could foster immunity against a new pathogen. By mating in a large panmictic population, new rare alleles can be recruited, which can then be combined into new genotypes through recombination with useful alleles of other genes. Bee breeders, by selecting small samples from a large population tend to select common alleles and lose the rare ones. Rare alleles can become important when a new virulent pathogen arrives. The loss of rare alleles makes bees vulnerable to disease and parasites and explains, together with the problems caused by modern agriculture, why managed bees have high mortality rates.
ARTICLE | doi:10.20944/preprints202310.0931.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Hermetia illucens; growth performance; sustanability; coffee sirvelskin; microalgae
Online: 16 October 2023 (08:01:37 CEST)
Hermetia illucens is a very promising insect due to its ability to convert low-value substrates in highly nutrient feed. Its feeding and nutrition are important issues. This work aimed to study the effect of different substrates composed of coffee silverskin, by-product of the roasting process, enriched with different inclusion of microalgae (5%, 10%, 20%, 25%), Schizochytrium limacinum and Isochrysis galbana, coupled with the assessment of environmental sustainability by LCA. In general, the inclusion of microalgae caused an increase in the growth performance of the larvae, although S. limacinum showed the best results. Higher prepupal weight were observed in larvae fed on 20% and 25% of S. limacinum, shorter development times in larvae fed on 25% of both S. limacinum and I. galbana and higher growth rate were observed in larvae fed on 25% of S. limacinum. Anyway, the inclusion of 10% of S. limacinum showed a small difference with the higher inclusions. Moreover, the 10% of S. limacinum achieved the best waste reduction index. Therefore, considering the greater inclusion of microalgae, the higher the environmental impact of larvae production, the addition of 10% of S. limacinum seems to be the best compromise for the larval rearing.
ARTICLE | doi:10.20944/preprints202310.0752.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Hymenoptera; natural enemies; citrus; citrus blackfly; orange spiny whitefly; Encarsia perplexa; Amitus hesperidum; Aleurocanthus woglumi
Online: 12 October 2023 (03:22:55 CEST)
Whiteflies of Aleurocanthus spiniferus and A. woglumi (Hemiptera: Aleyrodidae) are serious pests of citrus and other important fruit crops. The problem in citrus has initiated the successful introductions of several natural enemies for biocontrol programs in Hawaii and many other countries. Here we summarized the history of infestation and biocontrol efforts of the two whiteflies in Hawaii for possible importation into Greece. Two Platygasteridae (Amitus hesperidum Silvestri, A. spiniferus (Brethes) and three Aphelinidae (Encarsia clypealis (Silvestri), E. smithi (Silvestri), E. perplexa Huang and Polaszek) were released in Hawaii for biocontrol of the citrus whiteflies during the period 1974-1999. The aphelinid, Cales noacki Howard, purposely released for Aleurothrixus flococcus (Maskell) in 1982 was also reported to attack other whiteflies including Aleurocanthus species on citrus. An additional aphelinid parasitoid, Encarsia nipponica Silvestri, native to Japan and China, was accidently introduced and found to attack both citrus whiteflies on the islands. Since the colonization of introduced parasitoids in infested fields on four Hawaiian Islands, no survey was done to evaluate their potential impact. We made two short surveys during September-November 2022 on Kauai, Hawaii, and Oahu Islands to introduce the dominant parasitoids to Greece for the biocontrol of A. spiniferus. Results showed that the infestation level was very low on Kauai, Hawaii, and Oahu Islands with mean infestation level ranged 1.4 - 3.1 on Hawaii and Oahu Islands mostly on pummelo and sweet orange, with no detection on Kauai Island. Only was E. perplexa the dominant parasitoid with parasitism rates ranged 0 -28 % on Hawaii Island and 11-65% on Oahu Island. Starter colony of the parasitoids has been colonized in Greece for evaluation and approval for release. This was the first field survey on Hawaii since the introduction and release of citrus whitefly natural enemies.
ARTICLE | doi:10.20944/preprints202310.0479.v1
Subject: Biology And Life Sciences, Insect Science Keywords: trehalose-6-phosphate synthase; rapid cold hardening; trehalose metabolism; cold resistance; rice water weevil
Online: 9 October 2023 (11:16:47 CEST)
RCH is known rapidly enhance cold tolerance of insects. Trehalose has been demonstrated to be one of the cryoprotectant in L. oryzophilus, an important invasive pest of rice in China. Trehalose synthesis mainly occurs through the TPS/TPP pathway in insects. In this study, LoTPS gene was cloned and characterized for the first time. Its expression and trehalose content changes elicited by RCH were investigated. Our results revealed that RCH not only increased the survival rate of adults but also upregulated the gene expression level of LoTPS and increased trehalose content under low temperature. We hypothesized upregulated LoTPS promoted trehalose synthesis and accumulation to protect adults from low-temperature damage. To further verify the function of LoTPS gene, we employed RNAi technology. Our findings showed that RCH efficiency disappeared and failed to increase the survival rate when the adults were fed dsRNA of LoTPS. Additionally, inhibiting LoTPS gene expression resulted in no significant difference in trehalose content between RCH and non-RCH treatments. Furthermore, the expression patterns of TRET and TRE were also affected. Collectively, these results indicate the critical role of LoTPS in L. oryzophilus cold resistance after RCH induction. LoTPS can enhance the survival ability by regulating trehalose metabolism. These findings contribute to further understanding of the role of TPS in insect cold resistance and invasiveness of L. oryzophilus. Moreover, RNAi of the LoTPS opens up possibilities for novel control strategies against L. oryzophilus in the future.
ARTICLE | doi:10.20944/preprints202309.2104.v1
Subject: Biology And Life Sciences, Insect Science Keywords: extinct lauxaniid flies; age of Acalyptratae; Paleogene
Online: 29 September 2023 (10:57:05 CEST)
Hemilauxania parvula sp. nov., a new fossil species of the family Lauxaniidae (Diptera: Acalyptratae), is described and illustrated from Oise amber, France (Eocene, lower Ypresian, ca 53 Ma) and its relationship is discussed. Inasmuch as this first finding of a member of Schizophora in Oise amber probably represents the oldest known record of this group of Diptera, the age of Schizophora, based on the known fossil records, is discussed.
ARTICLE | doi:10.20944/preprints202309.1810.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Glossina morsitans; Rabbits; Guinea pigs; Rodents; Squirrels; bloodfed; and attracted
Online: 26 September 2023 (16:12:13 CEST)
The success of any tsetse control programs depends on the knowledge of their behaviour. This study assessed the host choice and feeding behaviours of Glossina morsitans’ siblings whose parents were bloodfed on Rabbits, Guinea pigs, Rodents and Squirrels. Individual host was placed in a screen cage which allowed flies to enter through openings on each side. The groups of flies (20 per replicate) colour-marked differently basing on their parents’ bloodmeal hosts, were released from the centre of large semi-field cage. Released flies were aspirated after 24 hours, then, sorted basing on the location, feeding status and parents’ bloodmeal. A total of 213 flies (72.95% of the recovered) were attracted to the hosts. The number of flies attracted to different hosts varied significantly (χ²4= 33.685, p= 0.0001); Rodent (n=80, p=0.006), Rabbit (n=59, p=0.331), Guinea pig (n=49, p=0.057) and squirrel (n=25, p=0.005). The number of flies attracted to their parent’s blood meal source varied significantly (χ²12 = 56.476, p<0.001); rabbits (n= 35, 59.32%, p<0.001), rodent (n=25, 31.25%, p=0.043) and guinea pig (n= 19, 38.78%, p=0.45). But, only 39 flies (18.31% of total attracted) bloodfed on the hosts; Guinea pigs (n=10, 25.64%), Rodents (n=23, 58.97%), Rabbits (n=6, 15.38%) and Squirrels (n=0,0.0%). There was significant variation in number of flies that fed successively across hosts (χ²4=49.478, p<0.001). The findings from this study confirms the presence of the hosts’ differential attractiveness to flies but failed to explain observed behaviours with reference to genetic inheritance. Therefore, the study attracts the need for detailed investigation on the influence of bloodmeal sources on tsetsefly siblings’ behaviours across filial generations using small mammals.
ARTICLE | doi:10.20944/preprints202309.1695.v1
Subject: Biology And Life Sciences, Insect Science Keywords: yellow mealworm, edible insects, by-products, rearing substrates, fatty acid, nutraceutical, antioxidant, lycopene, β-Carotene
Online: 26 September 2023 (04:33:31 CEST)
Tomato pomace (TP), an agricultural industrial waste product from the tomato processing industry, was valorized by being used as a rearing substrates for Tenebrio molitor (L.). This study evaluated bran-based diets with increasing tomato pomace (0%, 27%, 41% and 100%). Protein sources, as brewer’s spent grain and yeast, are used in TP27 and TP41 diets, respectively, to ensure equal protein content to control diet (TP0). Results showed larval survival, larval and pupal weight no different between diets; however, growth time significantly increases in TP100 compared at all diets. The feed conversion rate progressively increases from 2.7 to 4.3, respectively from TP0 to TP100. Conversely, Lycopene and β-Carotene increases in the larvae. Fatty acid composition improves by increasing polyunsaturated fatty acids (mainly -Linoleic acid). Although the best nutritional quality was obtained in T100, the TP41 is the optimal diet for balance between larval performance and qualitative improvement of larvae. Therefore, tomato pomace is suitable for the formulation of mealworm diets, even in high dosages when supplemented with sustainable protein sources.
REVIEW | doi:10.20944/preprints202309.1089.v2
Subject: Biology And Life Sciences, Insect Science Keywords: insect vector; host plant; plant virus; virus detection; virus transmission
Online: 22 September 2023 (05:18:27 CEST)
The phytophagous insect pests were vectors and could transmit the majority of the phytoviruses to their host plants. The orders of Hemiptera and Thysanoptera were the most common vectors of phytoviruses. The orders Orthoptera, Dermaptera, Coleoptera, Lepidoptera, Diptera, Thysanoptera, and Hemiptera were also the vectors of phytoviruses. Furthermore, aphids, whiteflies, cicadas, spittlebugs, leafhoppers, planthoppers, assassin bugs, plant bugs, stink bugs, lygaeid bugs, and thrips were among the most phytophagous insects that vector and transmit phytoviruses to healthy plants. The occurrence of a single species of these phytophagous insects resulted in one or more phytoviruses in general, and the Hemipteran order, in particular, vectored a lot of phytoviruses species. This review manuscript is focused on vectors of phytoviruses, techniques for their detection, and future directions. It will play a vital role in exploring scientific information concerning the interactions of phytoviruses and vector insects, the effect of phytoviruses on host behavior, mediators of phytoviruses transmission, persistent phytoviruses, some other insect vectors of the phytopathogen, mechanisms of host plant resistance against phytoviruses, and techniques of phytoviruses detection, as well as some important points to be considered in the future sustainably.
ARTICLE | doi:10.20944/preprints202309.1438.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Locust; Phase change; Outbreak; Solitarious; Gregarious; Model
Online: 21 September 2023 (08:49:02 CEST)
Outbreaks of the desert locust Schistocerca gregaria affect some of the poorest parts of Africa, causing devastating catastrophes. Key to understanding and dealing with this problematic adaptation to environmental changes is comparing locusts that are gregarious (associated with outbreak states) and solitarious (associated with non-outbreak states) either in nature or after experimental treatments in laboratories. Categorising locusts and detecting changes in their phase status is key to such comparisons. Such comparisons are hitherto based on applying mathematical models that use behavioural parameters and that each laboratory has to build a new for each experiment. All such models used thus far for research on locusts are different from each other. That implies differences in the tools used for the different experiments and by the different laboratories and, thus, potential noise in the scientific results and interpretations too. Standardizing the way how we categorise locusts between laboratories and experiments is needed if we want to reduce noise and errors. It is even a must if we are to make the results and interpretations transferable and comparable between experiments and laboratories that work in such an important research area. Here, we use samples from independent S. gregaria population in order to further test the two models that were suggested earlier as standardizing tools for S. gregaria categorization. The outcomes of both models were largely replicated and reproducible. We report on how successful the two models were at categorizing solitarious, intermediate (transient) and gregarious nymph and adult samples. We highlight shortcomings and make more specific recommendations on the use of these models based on the differences they show as to their precision when categorizing the solitarious and gregarious S. gregaria nymph and adult samples.
ARTICLE | doi:10.20944/preprints202309.1104.v1
Subject: Biology And Life Sciences, Insect Science Keywords: spotted lanternfly; chorion; egg respiration; aeropyles
Online: 18 September 2023 (02:56:54 CEST)
Knowledge regarding egg morphology can aid the selection of postharvest fumigants for insect control. Accordingly, scanning electron microscopy (SEM) was used to examine eggs of spotted lanternfly (SLF), Lycorma delicatula (White) (Hemiptera: Pentatomidae), a pest recently invasive to the mid-Atlantic region of the United States. As the overwintering life stage of SLF, eggs are deposited on a variety of refugia, including many forestry products that can be distributed geographically via travel, commerce, and/or trade. For fumigation to control SLF, and potentially translate into a viable strategy for limiting the spread of SLF by subject pathways, the fumigant must permeate the chorion to react with biomolecules and/or disrupt cellular processes. SLF chorion was characterized by a porous network of aeropyles localized around the operculum, in cranial and caudal relation to the developing nymph, as well as an interstice between the operculum edge and the opercular rim. The confirmation of chorionic ultrastructure that allows for ready gas exchange warrants further investigation of fumigation efficacy, even for those “non-reactive” fumigants, such as phosphine and hydrogen cyanide, which must overcome the suppression of cellular processes coincident with overwintering.
ARTICLE | doi:10.20944/preprints202309.1026.v1
Subject: Biology And Life Sciences, Insect Science Keywords: common bean; pests complex; abundance; insecticides; spray regimes
Online: 15 September 2023 (10:57:51 CEST)
In Uganda, the common bean (Phaseolus vulgaris) is often infested by a complex of insect pests, but the bean stem maggots, aphids, bean leaf beetles, and flower thrips are the most important. Whereas yield losses due to these pests have been established, there is limited information on their population dynamics at different stages of crop growth and their effect on yield and yield components. In order to describe the population dynamics of selected common bean pests at various phases of bean crop growth, and their impact on yield and yield components, a study was carried out in Uganda during 2016 second rains and 2017 first rains in three agro-ecological zones. Bean fly, bean aphids, bean leaf beetles, whitefly, striped bean weevil, leaf hoppers, and caterpillars of Lepidopteran species were the main insects observed. Pesticide spray schedules were imposed to generate different populations of insect pests whose effects on yield and its components were determined. The findings indicate that spray regimes significantly influenced the abundance of bean fly, aphids, whitefly, striped bean weevil, and leaf hoppers but not bean leaf beetles and caterpillars. Additionally, except caterpillars, insect pests were significantly influenced by crop growth stages, but only aphids, whiteflies, bean flies and leaf hoppers exhibited a significant negative relationship with grain yield. Furthermore, yield and yield components varied significantly between spray regimes, agro-ecological zones, and seasons. Our study is important in informing growers on the stage of crop growth at which management tactics such as use of insecticides can be applied for different insect pests.
ARTICLE | doi:10.20944/preprints202309.0941.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Biological control agents; Effectiveness; Parasitoid; Invasive pest
Online: 14 September 2023 (09:03:52 CEST)
Phenacoccus manihoti (Hemiptera: Pseudococcidae), is an invasive pest that is very detrimental to cassava cultivation in Indonesia. Control efforts by utilizing natural enemies of the parasitoid have succeeded in overcoming the cassava mealybug in 25 countries such as in Africa and Thailand. The purpose of this study was to specifically evaluate the potential for parasitoid species associated with the mealybug P. manihoti by (1) determining the level of parasitization against mealybugs on various varieties of cassava, (2) determining parasitoid preference for P. manihoti instars, and (3) determining the type of parasitoid. This study was undertaken in the field to re-evaluate the kinds of parasitoids associated with cassava pests, and in the laboratory to assess the amount of parasitization, predilection, and functional response of parasitoids to P. manihoti population density. The findings revealed three of parasitoids linked with P. manihoti in the field: Anagyrus lopezi, Acerophagus sp., and Blepyrus sp. The parasitoid A. lopezi had the greatest parasitization rate in the field, which was 18.67 %. Furthermore, the parasitoids A. lopezi and Blepyrus sp. preferred 3rd instar nymphs, but Acerophagus sp. preferred 2nd instar nymphs. The parasitoid A. lopezi demonstrated a type-III functional response, while Acerophagus sp. and Blepyrus sp. demonstrated a type-II functional response. The handling capacity (Th) of A. lopezi is the shortest at 3.42 minutes. This work is a comprehensive study of the parasitoid A. lopezi's potential as a biological agent, highlighting how it effectively suppresses P. manihoti on various cassava varieties in Bali, providing an inexpensive, environmentally friendly, and applicable control in tropical countries.
REVIEW | doi:10.20944/preprints202309.0368.v1
Subject: Biology And Life Sciences, Insect Science Keywords: South Africa, locust outbreak dynamics, brown locust, red locust, African migratory locust, southern African desert locust
Online: 6 September 2023 (14:32:26 CEST)
The current paper provides a detailed review of the historical outbreaks of each of the four plague locust species found in South Africa, namely the brown locust, the African migratory locust, the red locust and the southern African desert locust. The history and dynamics of the plague infestations and the major local outbreaks are summarized. The typical patterns of the outbreaks of the different species are described and the threat of these locusts to agriculture in South Africa is defined. The brown locust produces regular outbreaks in the semi-arid Karoo, with large-scale eruptions of plague proportions occurring once or twice per decade. Patterns of outbreaks often repeat themselves, but the sheer size of the plague outbreaks are almost impossible to stop and the brown locust has the potential to threaten food security throughout southern Africa. The African migratory locust produces outbreaks in some of the main maize and wheat cropping areas where it is difficult to control. This locust has taken advantage of the man-made crop environment to produce an extra generation per year that was not previously possible in the original grasslands. The coastal area of KwaZulu Natal in South Africa was a prime reception and breeding area for plague invasions of the red locust in the past and the country therefore relies on the successful control of outbreaks in east and central Africa into prevent the recurrence of the plague invasions. The southern African desert locust occurs in the Kalahari Desert area and outbreaks requiring chemical control are rare.
REVIEW | doi:10.20944/preprints202309.0258.v1
Subject: Biology And Life Sciences, Insect Science Keywords: sweetpotato; weevils; Cylas spp.; resistance; breeding; Uganda
Online: 5 September 2023 (09:13:20 CEST)
In sub-Saharan Africa, sweetpotato weevils are the most devastating pests of cultivated sweetpotato, causing estimated losses of between 60% and 100%, primarily during dry spells. The predominantly cryptic feeding behavior of the Cylas spp within the roots makes their control difficult, thus host plant resistance is one of the most promising lines of protection against these pests. However, progress in breeding for weevil-resistant cultivars has been slow in part due to the complex hexaploid genome of sweetpotato, which complicates conventional breeding in addition to the scarcity of varieties with significant levels of resistance for use as sources of resistance. Pollen sterility, cross incompatibility and poor seed set and germination in sweetpotato are also common challenges to improving weevil resistance. Accurate phenotyping of sweetpotato weevil resistance to enhance efficiency of selection has been equally difficult. Genomics-assisted breeding though in its infancy stages in sweetpotato has the potential application in overcoming some of these barriers. However, it will require the development of more genomic infrastructure; particularly single nucleotide polymorphism markers (SNPs), robust next generation sequencing plat-forms together with relevant statistical procedures for analyses. With the recent advances in genomics, we anticipate that genomic breeding for sweetpotato weevil resistance will be expedited in the coming years. This review sheds light on Uganda's efforts to date to breed against the Cylas puncticollis (Boheman) and Cylas brunneus (Fabricius) species of African sweetpotato weevil.
ARTICLE | doi:10.20944/preprints202308.1674.v3
Subject: Biology And Life Sciences, Insect Science Keywords: China; Sycanus; taxonomy; DNA barcoding; species delimitation; phylogeny; new species; biology
Online: 5 September 2023 (02:40:40 CEST)
Due to the variation of the body coloration and the similarity of the related species, there are still some unresolved problems and debates in the taxonomic study of the genus Sycanus in China. We conducted the inter-specific phylogenetic analyses and the species delimitation for Sycanus in China based on DNA barcoding dataset of the mitochondrial cytochrome c oxidase subunit I gene of 81 samples and partial 28S rDNA sequences of 34 samples. The result showed that all the samples were divided into twelve species by integrating the results of DNA barcoding and morphological comparison. In the present paper, the genus Sycanus in China was reviewed systematically, all species were described or re-described, keyed, illustrated and photographed, among them, Sycanus taiwanensis Zhao & Cai sp. nov., Sycanus flavicorius Li & Cai sp. nov. and Sycanus hainanensis Wang & Cai sp. nov. were described as new to science. The biological informations of Sycanus falleni Stål, 1863 and Sycanus croceus Hsiao, 1979 were briefly recorded.
ARTICLE | doi:10.20944/preprints202309.0074.v1
Subject: Biology And Life Sciences, Insect Science Keywords: escamoles; life cycle; social insects; chemical communication; electronic nose
Online: 4 September 2023 (03:08:40 CEST)
Ants have a very sophisticated olfactory system; their communication is based on the interpretation of chemical trails known as semiochemicals. The escamolera ant (Liometopum apiculatum), has behaviors and physiological responses is induced by semiochemicals, without however, these have not been studied. Using an electronic nose analysis (e-nose) and chromatographic techniques, semiochemicals of L. apiculatum in nests, foraging trails and dissected the gasters were evaluated. Data were analyzed with multivariate statistics and a logistic regression model based on predictors (ant counts) and the semiochemicals identified in pre-season (PRE), season (TEM) and post-season (POS) of larval collecting. From the general pattern of volatiles with a natural separation in POS and a partial distribution between PRE and TEM 32 semiochemicals were identified inside the nests, those who can induce the behavioral responses of trail-following, alarm, aggression, and nestmate recognition. Trail counts indicated that ant traffic was higher in POS and that the presence of certain semiochemicals (response variable) have good fit in the model regression. These findings are intended to provide useful information and support decision-making for the conservation and sustainable use of L. apiculatum in central Mexico.
ARTICLE | doi:10.20944/preprints202308.2202.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Insect transgenesis; Aedes; Drosophila suzukii; tephritids; transformation efficiency; recombination efficiency; piggyBac transposase; helper plasmid; capped mRNA
Online: 1 September 2023 (14:00:54 CEST)
Creating transgenic insects is a key technology in insect genetics and molecular biology. A widely used instrument in insect transgenesis is the piggyBac transposase, resulting in essentially ran-dom genomic integrations. In contrast, site-specific recombinases allow the targeted integration of the transgene construct into a specific genomic target site. Both strategies, however, often face limitations due to low transgenesis rates. We aimed to enhance transgenesis rates by utilizing a capped mRNA as a source of transposase or recombinase instead of a helper plasmid. A system-atic comparison of transgenesis rates in Aedes mosquitoes, as models for hard to transform in-sects, showed that suppling piggyBac transposase as mRNA increased the average transfor-mation efficiency in Aedes aegypti from less than 5% with the plasmid source to about 50% with mRNA. Similar high transformation activity was observed in Ae. albopictus with pBac mRNA. No efficiency differences between plasmid and mRNA were observed in recombination experi-ments. Furthermore, a codon-optimized version of piggyBac transposase delivered as plasmid didn’t improve the transformation efficiency in Ae. aegypti or the agricultural pest D. suzukii. We believe that the use of mRNA has strong potential for enhancing pBac transformation efficiencies in other mosquitoes and important agricultural pests such as tephritids.
ARTICLE | doi:10.20944/preprints202308.2189.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Macadamia; Acanthococcus ironsidei; Metaphycus macadamiae; Encyrtidae; Hawaii
Online: 31 August 2023 (13:15:54 CEST)
Macadamia Felted Coccid (MFC), Acanthococcus ironsidei (Williams) (Hemiptera: Eriococcidae) was first discovered in 2005 on the Island of Hawaii. Host plants are restricted to Macadamia species, with Macadamia integrifolia Maiden & Betche (Proteaceae) being grown in Hawaii for nut production. Approximately 16,900 acres of macadamia nuts are harvested in Hawaii with estimated farm value of $ 48.8 million (2019 - 2020 records). MFC has become a problem in macadamia orchards where heavy infestations cause the death of young seedlings, reduction in nut production, and severe damage can eventually kill affected trees. Chemical control and extant natural enemies have not suppressed the population of MFC to a manageable level. Exploration in Australia started in November 2013 for the evaluation of potential parasitoids being host specific for introduction into Hawaii. A dominant solitary endoparasitoid of MFC from New South Wales was discovered and described as Metaphycus macadamiae Polaszek & Noyes sp. n (Hymenoptera: Encyrtidae: Encyrtinae). Biology and host specificity testing were conducted at the Hawaii Department of Agriculture, Insect Containment Facility on nine Hemipteran and three Lepidopteran eggs. Results indicated that M. macadamiae is host specific to MFC. There has been no evidence of parasitism or host feeding on any of the non-target insect hosts that were tested. Parasitoid emergence from the control (MFC) averaged 30.2% compared to 0% on non-target hosts. Low rate of parasitoid emergence in the laboratory (average 30.2 %), and increased rate of MFC nymphal mortality was due to adult feeding. Percent field parasitism reached up to 32.7% emergence in the NSW Alstonville, Australia. We report on the parasitoid performance in native Australia, rearing biology, host specificity testing, and the extant natural enemies associated with MFC in Hawaii. A petition to release this parasitoid for the biocontrol of MFC in Hawaii is pending. Once permitted for release, the colony will be shared with South African Mac Nut Association for their biocontrol program of this invasive pest. They will conduct their own testing before approval for release.
ARTICLE | doi:10.20944/preprints202308.1364.v1
Subject: Biology And Life Sciences, Insect Science Keywords: biodiversity; COI; DNA barcoding; insects; Lepidoptera; Polyommatus; taxonomy
Online: 18 August 2023 (10:32:50 CEST)
The need for multi-gene analysis in evolutionary and taxonomic studies is generally accepted. However, sequencing of multiple genes is not always possible. For various reasons, short mito-chondrial DNA barcodes are the only source of molecular information for some species in many genera, although multilocus data are available for other species of the same genera. In particular, such a situation exists in the species-rich butterfly subgenus Polyommatus (Agrodiaetus). Here, we analysed partitioning of this subgenus into species groups by using three data sets. The first data set was represented by short mitochondrial DNA barcodes for all analysed samples. The second and third data sets were represented by combination of short mitochondrial DNA barcodes for a part of the taxa with longer mitochondrial sequences COI+tRNA-Leu+COII (data set 2) and with longer mitochondrial COI+tRNA-Leu+COII and nuclear 5.8S rDNA+ITS2+28S rDNA sequences (data set 3) for the remaining species. We show that DNA barcoding approach (data set 1) failed to reveal the taxonomic structure resulting in numerous polytomies in the phylogenetic tree ob-tained. Combined analysis of the mitochondrial and nuclear sequences (data sets 2 and 3) re-vealed the species groups and position within these species groups even for the taxa for which only short DNA barcodes were available.
ARTICLE | doi:10.20944/preprints202308.1326.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Lygus lineolaris; pyrethroids binary mixtures; bioassay; resistance management; synergism; toxicity
Online: 18 August 2023 (08:25:47 CEST)
Over the past several decades, the extensive use of pyrethroids has led to the development of resistance in many insect populations, including the economically damaging pest tarnished plant bug (TPB), Lygus lineolaris on cotton. To manage TPB resistance, several commercially formulated pyrethroid-containing binary mixtures, in combination with neonicotinoids or avermectin are recommended for TPB control and resistance management in the Mid-south USA. This study aimed to evaluate the toxicity and resistance risks of four formulated pyrethroid-containing binary mixtures (Endigo, Leverage, Athena, and Hero) on one susceptible and two resistant TPB populations which were field-collected in July (Field-R1) and October (Field-R2), respectively. Based on LC50 values, both resistant TPB populations displayed variable tolerance to the four binary mixtures, with Hero showing the highest resistance and Athena the lowest. Notably, the Field-R2 exhibited 1.5-3-fold higher resistance compared to the Field-R1 for all four binary insecticides. Moreover, both resistant TPB populations demonstrated significantly higher resistance ratios toward Hero and Leverage compared to their corresponding individual pyrethroid, while Endigo and Athena showed similar or lower resistance. This study also utilized the calculated additive index (AI) and co-toxicity coefficient (CTC) analysis, which revealed that the two individual components in Leverage exhibited antagonist effects against the two resistant TPB populations. In contrast, the two individual components in Endigo, Hero and Athena displayed synergistic interactions. Considering that Hero is a mixture of two pyrethroids which can enhance the development of TPB resistance, our findings suggest that Endigo and Athena are likely superior products for slowing down resistance development in TPB populations. This study provides valuable insight for selecting the most effective mixtures to achieve better TPB control through synergistic toxicity analysis, while simultaneously reducing economic and environmental risks associated with resistance development in the insect pest.
REVIEW | doi:10.20944/preprints202308.0354.v1
Online: 4 August 2023 (03:15:26 CEST)
Notch signaling is a highly conserved pathway which occurs between adjacent cells to distinguish them. The Notch signaling cascade operates in a simple mechanism, yet Notch plays remarkably diverse roles in development to regulate cell fate determination, organ growth and tissue patterning. Originally isolated and characterized in the model insect Drosophila melanogaster, recent studies in various insect species have revealed that Notch signaling is broadly involved in the construction of insect tissues. This review focuses on providing a molecular mechanistic and developmental picture regarding the roles of Notch pathway in insects. The functions of Notch in the formation and patterning of insect embryo, wing, leg, ovary and several specific structures as well as in stress responses are summarized. These results are discussed in developmental context with an eye toward understanding the functionality of Notch signaling pathway in different insect species.
ARTICLE | doi:10.20944/preprints202308.0188.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Hylogomphus geminatus; ecomorphology; Odonata; watershed; landcover
Online: 3 August 2023 (02:34:32 CEST)
Anthropogenic land-cover change is modifying ecosystems at an accelerating rate. Changes to ecomorphologically variable taxa within those ecosystems serve as early-warning signs that resources on which humans and other animals depend are being altered. One known ecomorphologically variable taxon is Hylogomphus geminatus, a species of dragonfly in the southeastern United States that shows pronounced variation in total body length across its limited geographic range. We measured total length of live as well as preserved museum specimens of H. geminatus and the sympatric species Progomphus obscurus (as a means for comparison). Both species showed significant size differences by HUC-8 watersheds in which they occur. H. geminatus showed additional significant differences on either side of the Apalachicola River, Florida, for all comparisons by sex. In overlapping watersheds, the species tended to show the same trends in size relative to their respective averages. Smaller body size was associated with more urban and agricultural land cover. These findings indicate that ecomorphological variation is tied to the watershed scale and point to significant variations on either side of the Apalachicola River. More focused research and continuous stream monitoring should be implemented to understand the extent that phenotypic plasticity plays in this variation.
ARTICLE | doi:10.20944/preprints202307.0436.v2
Subject: Biology And Life Sciences, Insect Science Keywords: Phytosanitary irradiation; Paracoccus marginatus; dose-response test; large-scale confirmatory test.
Online: 21 July 2023 (10:21:54 CEST)
The papaya mealybug Paracoccus marginatus is an invasive, polyphagous pest and poses a quarantine threat to tropical and subtropical countries. Infested commodity internationally should be undergoing phytosanitary treatment, while irradiation is recommended to replace methyl bromide fumigation. Dose-response tests were conducted on the 2-, 4-, and 6-d-old eggs and gravid females of P. marginatus using the X-ray radiation doses of 15–105 Gy with an interval of 15 Gy, respectively. Radiotolerance was compared using fiducial overlapping and lethal dose ratio (LDR) test, resulting in insignificant difference except for LDR test at LD90 (leading 90% mortality at 95% confidence level (CL)); the estimated dose for 99.9968% mortality at 95% CL was 176.5–185.2 Gy, which was validated in the confirmatory tests using gamma irradiation because gammy and X-rays have equal biological effect on pests. Therefore, a total of estimating 60,386 gravid females of papaya mealybug irradiated with 146.8–185.0 Gy resulted in no F1 nymphs developing. Eggs can therefore be used as an alternative to gravid females for dose-response tests; the recommended minimum dose for phytosanitary treatment of P. marginatus on infested commodity is 185 Gy, with treatment efficacy ≥ 99.9950% at 95% CL.
ARTICLE | doi:10.20944/preprints202307.1322.v1
Subject: Biology And Life Sciences, Insect Science Keywords: hymenoptera; olfaction; odor coding; task allocation; age polyethism; aging
Online: 19 July 2023 (10:03:17 CEST)
Age-related changes in behavior and sensory perception have been observed in a wide variety of animal species. In ants and other eusocial insects, workers often progress through an ordered sequence of olfactory-driven behavioral tasks. Notably, these behaviors are plastic, and workers adapt and rapidly switch tasks in response to changing environmental conditions. In the Florida carpenter ant, smaller minors typically perform most of the work needed to maintain the colony while the larger majors are specialized for nest defense and rarely engage in these routine tasks. Here, we investigate the effects of age and task group on olfactory responses to a series of odorant blends in minor and major worker castes. Consistent with their respective roles within the colony, we observed significant age-associated shifts in the olfactory responses of minors as they transitioned between behavioral states, whereas the responses of majors remained consistently low regardless of age. Furthermore, we identified a unitary compound, 3-methylindole, which elicited significantly higher responses and behavioral aversion in minor nurses than in similarly aged foragers suggesting that this compound may play an important role in brood care. Taken together, our results suggest that age- and task-associated shifts in olfactory physiology may play a critical role in the social organization of ant colonies.
ARTICLE | doi:10.20944/preprints202307.1027.v1
Subject: Biology And Life Sciences, Insect Science Keywords: spittlebug; cercopid; aphrophora; walker; biochemistry; foam
Online: 17 July 2023 (10:37:14 CEST)
The aim of this study was to analyze the chemical composition of nymphal envelopes (foam) collected from hemipterans from spittlebug belonging to the species Aphrophora alni (Hemiptera family Aphrophoridae). Foam was collected in Poland in the Mazowieckie Voivodeship in 2020- 2022. Foam was collected from nymphs, feeding on young leaves of black alder trees (Alnus glutinosa), from 12 different areas. For the first time, the chemical composition of the foam produced by the spittlebug was quantitatively analyzed, identifying from 73.76 to 93.21 percent. The analyzed samples consisted mainly of a carbohydrate polymer similar in sugar unit composition to fucoidate isolated from brown seaweed. The most important sugar units identified were fucose (17.0 % - 35.6 % of the dry weight of the secretion), glucose (6.1 % - 16.2 %), mannose (1.5 % - 9.9 %), rhamnose (0.4 % - 1.3 %) and xylose (0.06 % - 0.1 %). In addition, various fatty acids, myo-inositol, pinitol, aliphatic hydrocarbons, waxes and aliphatic derivatives of 2(3H)-furanone were found. The collected foam contained from 0.05 % to 0.1 % of dry matter. Significant changes in the chemical composition of nymphal envelopes were found depending on the year of collection, which is probably strongly related to climate change.
ARTICLE | doi:10.20944/preprints202307.0753.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aedes aegypti; insecticide resistance; RNA-Seq; detoxification genes; mosquitoes; Puerto Rico; organophosphate resistance; pyrethroid resistance
Online: 12 July 2023 (07:55:39 CEST)
Aedes aegypti transmits major arboviruses of public health importance, including dengue, chikungunya, Zika, and yellow fever. The use of insecticides represents the cornerstone of vector control, however insecticide resistance in Ae. aegypti has become widespread. Understanding the molecular basis of insecticide resistance in this species is crucial to design effective resistance management strategies. Here, we applied Illumina RNA-Seq to study the gene expression patterns associated with resistance to three widely used insecticides (malathion, alpha-cypermethrin and lambda-cyhalothrin) in Ae. aegypti populations from 2 sites (Manatí and Isabela) in Puerto Rico (PR). Cytochrome P450s were the most over-expressed detoxification genes across all resistant phenotypes. Some detoxification genes (CYP6Z7, CYP28A5, CYP9J2, CYP6Z6, CYP6BB2, CYP6M9, and two CYP9F2 orthologs) were commonly over-expressed in mosquitoes that survived exposure to all three insecticides (independent of geographical origin) while others including CYP6BY1 (malathion), GSTD1 (alpha-cypermethrin), CYP4H29 and GSTE6 (lambda-cyhalothrin) were uniquely overexpressed in mosquitoes that survived exposure to specific insecticides. The gene ontology (GO) terms associated with monooxygenase, iron binding, and passive transmembrane transporter activities were significantly enriched in 4 out of 6 resistant vs susceptible comparisons while serine protease activity was elevated in all insecticide resistant groups relative to the susceptible strain. Interestingly, cuticular-related protein genes (chinase and chitin) were predominantly downregulated, which was also confirmed in the functional enrichment analysis. This RNA-Seq analysis presents a detailed picture of the candidate detoxification genes and other pathways that are potentially associated with pyrethroid and organophosphate resistance in Ae. aegypti populations from PR. These results could inform development of novel molecular tools for detection of resistance-associated gene expression in this important arbovirus vector and guide the design and implementation of resistance management strategies.
ARTICLE | doi:10.20944/preprints202307.0149.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aedes albopictus; Bayesian model; MCMC; ovitraps; climate change
Online: 4 July 2023 (05:26:17 CEST)
Background: Aedes albopictus, the Asian Tiger Mosquito, has become a prevalent pest in Italy, causing severe nuisance and posing a threat of transmission of arboviruses introduced by infected travellers. In this study, we investigated the influence of weather parameters on the seasonal population density of Aedes albopictus. Methods: A Bayesian approach was employed to identify the best meteorological predictors of species trend, using the eggs collected monthly from 2010 to 2022 by the Emilia-Romagna regional monitoring network. Results: The findings show that the winter-spring period (January to May) plays a crucial role in the size of the first generation and seasonal development of the species. Conclusions: A temperate winter and a dry and cold March, followed by a rainy and hot spring and a rainy July, seem to favour the seasonal development of Ae. albopictus.
ARTICLE | doi:10.20944/preprints202306.2081.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Allelochemical; Bt toxin; chemical insecticide; combined toxicity; induced toxicity; synergistic interactions
Online: 29 June 2023 (09:49:30 CEST)
Target pests of genetically engineered crops producing both defensive allelochemicals and Bacillus thuringiensis (Bt) toxins often sequentially or simultaneously uptake allelochemicals, Bt toxins, and/or insecticides. How the three types of toxins interact to kill pests remains underexplored. Here we investigated the interactions of Bt toxin Vip3A, plant allelochemical flavone, and insecticide emamectin benzoate in Spodoptera frugiperda. Simultaneous administration of flavone LC25 + Vip3A LC25, emamectin benzoate LC25 + Vip3A LC25, and flavone LC15 + emamectin benzoate LC15 + Vip3A LC15 but not flavone LC25 + emamectin LC25 yielded a mortality significantly higher than their expected additive mortality (EAM). One-day preexposure to one toxin at LC5 followed by 6-day exposure to the same toxin at LC5 plus another toxin at LC50 showed that the mortality of flavone LC5 + Vip3A LC50, emamectin benzoate LC5 + Vip3A LC50, and Vip3A LC5 + emamectin benzoate LC50, were significantly higher than their EAM, while that of flavone LC5 + emamectin benzoate LC50 was significantly lower than their EAM. No significant difference existed among the mortalities of Vip3A LC5 + flavone LC50, emamectin benzoate LC5 + flavone LC50, and their EAMs. The results suggest that the interactions of the three toxins are largely synergistic (inductive) or additive, depending on their combinations and doses.
ARTICLE | doi:10.20944/preprints202306.1733.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Hemiptera; opsin; gene loss; color vision; compensatory neofunctionalization; tuning site
Online: 26 June 2023 (04:26:48 CEST)
Expanding previous efforts to survey the visual opsin repertoires of the Hemiptera, this study confirms that homologs of the UV- and LW-opsin subfamilies are conserved in all Hemiptera, while the B-opsin subfamily is missing from the Heteroptera and subgroups of the Sternorrhyncha and Auchenorrhyncha, i.e. aphids (Aphidoidea) and planthoppers (Fulgoroidea), respectively. Unlike in the Heteroptera, which are characterized by multiple expansions of the LW-opsin subfamily, the lack of B-opsin correlates with the presence of tandem-duplicated UV-opsins in aphids and planthoppers. Available data on organismal wavelength sensitivities and retinal gene expression patterns lead to the conclusion that, in both groups, one UV-opsin paralog shifted from ancestral UV peak sensitivity to derived blue sensitivity, thereby compensating for the lost B-opsin. Two parallel bona fide tuning site substitutions compare to 18 non-corresponding amino acid replacements in the blue-shifted UV-opsin paralogs of aphids and planthoppers. Most notably, while the aphid blue-shifted UV-opsin clade is characterized by a replacement substitution at one of the best-documented UV/blue tuning sites (Rhodopsin site 90), the planthopper blue-shifted UV-opsin paralogs retained the ancestral lysine at this position. The combined findings identify aphid and planthopper UV-opsins as a new valuable data sample for studying adaptive opsin evolution.
ARTICLE | doi:10.20944/preprints202306.1730.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Honey bee; identification; wings; geometric morphometrics; XML
Online: 26 June 2023 (02:58:04 CEST)
Identification of the honey bee (Apis mellifera) subspecies is an important aspect of bee breeding and biodiversity conservation. The identification can be based on molecular or morphological markers. For some markers, including the cytochrome c oxidase subunit, there is a well-established methodology allowing consistent subspecies identification in different laboratories. In the case of morphological markers, identification is hindered by a lack of reference data and a standardized methodology to reuse it. We show here that reference data for the identification of honey bees based on geometric morphometrics can be saved in an XML file. The information in this file can be easily extracted by other users for the identification of unknown samples. We illustrate this procedure using ten samples from north India. The samples were identified as A. mellifera; next, they were identified as lineage C; and finally, most of the samples had high similarity to honey bees from Croatia and Slovenia. We explained what data is required for such identification and how it can be reused. The method described here can be applied not only to honey bee wings but also to all data based on landmark coordinates.
ARTICLE | doi:10.20944/preprints202306.1363.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Baculoviridae; bioinsecticide; genotypic variant; pathogenicity; virulence; occlusion body production
Online: 19 June 2023 (13:23:00 CEST)
Outbreaks of Anticarsia gemmatalis (Hübner, 1818) (Lepidoptera: Erebidae), a major pest of soybean, can be controlled below economic thresholds with methods that do not involve the application of synthetic insecticides. Formulations based on natural isolates of the Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) (Baculoviridae: Alphabaculovirus), played a significant role in integrated pest management programs in the early 2000s, but a new generation of chemical insecticides and transgenic soybean, have displaced AgMNPV-based products over the past decade. However, the marked genotypic variability present among and within alphabaculovirus isolates suggests that highly insecticidal genotypic variants can be isolated and used to reduce virus production costs or overcome isolate-dependent host resistance. This study aimed to select novel variants of AgMNPV with suitable insecticidal traits that could comple-ment the existing AgMNPV active ingredients. Three distinct AgMNPV isolates were compared by restriction endonuclease profile and in terms of their occlusion body (OB) pathogenicity. One isolate was selected (AgABB51) from which eighteen genotypic variants were plaque purified and characterized in terms of their insecticidal properties. The five most pathogenic variants varied in OB pathogenicity although none of them was faster-killing or had higher OB production characteristics than the wild-type isolate. We conclude that the AgABB51 wild-type isolates ap-pear to be genotypically structured for fast speed-of-kill and high OB production, both of which would favor transmission. Interactions among the component variants are likely to influence this insecticidal phenotype.
ARTICLE | doi:10.20944/preprints202306.1093.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aedes albopictus; genetic sexing strain; insecticide selection; dieldrin quantification
Online: 15 June 2023 (07:45:18 CEST)
The mass production of mosquitoes at an industrial scale requires efficient sex separation, which can be achieved through mechanical, genetic or artificial intelligence means. Compared with others methods, the genetic sexing approach offers the advantage of limiting costs and space by removing females at larval stage. We recently developed a GSS in Aedes albopictus based on the sex linkage of the rdl gene to the M locus, conferring dieldrin resistance in males only. It has been previously reported that dieldrin ingested by larvae can be detected in adults and bioaccumulated in predators, raising the question of its use at a large-scale. In this context, we performed several experiments aiming at optimizing dieldrin selection by decreasing both dieldrin concentration and exposure time while maintaining a stable percentage of females averaging 1%. We showed that the previously used dieldrin exposure induced an important toxicity as it killed 60% of resistant males at larval stage. We could easily lower this toxicity by reducing the dose and/or the exposure time to recover nearly all resistant males. We then quantified the residues of dieldrin in resistant male adults and showed that dieldrin toxicity in larvae was positively correlated with dieldrin concentrations detected in adults. Interestingly, we showed that the use of reduced dieldrin exposure led to a dieldrin detection in adult males that was below the sensitivity threshold of the Gas Chromatography Mass Spectrometry detection method. Presented data show that dieldrin exposure can be adjusted to suppress toxicity in males while achieving efficient sexing and lowering the levels of dieldrin residues in adults to barely detectable levels.
ARTICLE | doi:10.20944/preprints202306.0837.v1
Subject: Biology And Life Sciences, Insect Science Keywords: New taxon; morphological characteristics; ITS2; Medicago sativa
Online: 12 June 2023 (13:16:07 CEST)
Three new species of the Sequester group of Pteromalus (Habrocytus) (Hymenoptera: Pteromalidae: Pteromalinae), Pteromalus (Habrocytus) boleensis Yan et Li sp. nov., Pteromalus (Habrocytus) longepedicelus Yan et Li sp. nov., and Pteromalus (Habrocytus) robustus Yan et Li sp. nov. are described and illustrated based on adult morphology and molecular data from Xinjiang, China. The DNA barcodes (ITS2) of Pteromalus (Habrocytus) boleensis sp. nov. and Pteromalus (Habrocytus) robustus sp. nov. have been generated and compared with all existing sequences of the Sequester species group. The results of morphological taxonomy and molecular identification are consistent. A key to all known species of the Sequester group in the world is provided.
REVIEW | doi:10.20944/preprints202306.0439.v1
Subject: Biology And Life Sciences, Insect Science Keywords: urban zone; mosquitoes; mapping; mosquito-borne diseases; stinkbugs; nuisance
Online: 6 June 2023 (10:07:51 CEST)
Urban environments are frequently populated by different insect species. Some of them are very beautiful and appealing to the people around them, such as ladybugs and butterflies, while some others are molestants and even dangerous to public health. Mosquitoes often inhabit urban environments by staying close to their hosts (humans, birds, etc.), while phytophagous species such as stinkbugs find hosts among ornamental plants and shelters during the winter around humans. This article describes the early discoveries and distribution of two invasive mosquito species, Aedes albopictus, and Ae. japonicus (Diptera: Culicidae), which were recorded in Serbia in 2009 and 2018, respectively. Both species are important for human health, due to their nuisance behavior and because they are vectors of many viruses. On the other hand, in 2015 and 2008, two invasive stinkbug species, Halyomorpha halys and Nezara viridula (Hemiptera: Pentatomidae) were observed to spread, respectively. Since then, these species have disrupted human population in urban areas, but also damaged a range of crops and ornamental plants. All species have been monitored in the territory of Serbia, and establishment and distribution have been confirmed so far.
ARTICLE | doi:10.20944/preprints202306.0327.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Circadian clock; Frankliniella occidentalis; Feeding; Mating; Behavior
Online: 5 June 2023 (13:35:11 CEST)
The western flower thrips, Frankliniella occidentalis, is invasive and polyphagous. Its visual signal plays a crucial role in host location, suggesting that thrips has diurnal behavior. However, any diel rhythmicity of the thrips behavior is not yet well understood. This study analyzed the diurnal rhythmicity of the feeding and mating behaviors of thrips, and the patterns were explained in terms of diel rhythmicity by assessing the expression of genes associated with the circadian clock. Most feeding behaviors were observed during photophase in both larvae and adults. In mating behavior, which is mainly exhibited in 2~3 days-old young adults after emergence, most adults copulated at photophase. This diurnal pattern of the mating behavior was further supported by the analysis of a temporal calling behavior for mating, which was biased toward photophase. Four genes associated with the circadian clock were predicted in the F. occidentalis genome: period (PER), Timeless (TIM), Doubletime (DBT), and clock (CLK). All these genes exhibited a characteristic diel pattern in their gene expressions in a 24 h-period. The high expression peaks of these genes except for DBT were observed at photophase. To confirm the functional association of these genes with the feeding and mating behaviors, individual RNA interference specific to each gene was executed by feeding the gene-specific double-stranded RNA. Aside from DBT, suppression of these gene expressions resulted in significant deviations of the diel rhythms of the behaviors. These results suggest that the genetic components of the diel rhythmicity mediate the diurnal feeding and mating behaviors of F. occidentalis.
ARTICLE | doi:10.20944/preprints202305.2074.v1
Subject: Biology And Life Sciences, Insect Science Keywords: phytohormone; auxin; insect gall; aromatic aldehyde synthase; inhibitor
Online: 30 May 2023 (07:58:03 CEST)
Gall-inducing insects often contain high concentrations of phytohormones, such as auxin and cytokinin, which are suggested to be involved in gall induction, but no conclusive evidence has been obtained. There are two possible approaches to investigating the importance of phytohormones in gall induction: demonstrating either that high phytohormone productivity can induce gall-inducing ability in non-gall-inducing insects, or that gall-inducing ability is inhibited when phytohormone productivity in galling insects is suppressed. In this study, we show that the overexpression of PonAAS2, which encodes an aromatic aldehyde synthase (AAS) responsible for the rate-limiting step in indoleacetic acid (IAA) biosynthesis in a galling sawfly (Pontania sp.) that contains high levels of endogenous IAA, conferred high IAA productivity on Caenorhabditis elegans, as the model system. This result strongly suggests that PonAAS2 can also confer high IAA productivity on low-IAA-producing insects. We also successfully identified an inhibitor of PonAAS2 in a chemical library. This highly selective inhibitor showed stronger inhibitory activity against AAS than against aromatic amino acid decarboxylase, which belongs to the same superfamily as AAS. We also confirm that this inhibitor clearly inhibited IAA productivity in the high-IAA-producing C. elegans engineered here.
ARTICLE | doi:10.20944/preprints202305.2028.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Juvenile hormone; Juvenile hormone binding protein; Silk protein; Bombyx mori
Online: 30 May 2023 (03:41:29 CEST)
Production of silkworm silk is the most economically important traits in the silk industry. Silk protein synthesis is regulated by juvenile hormone (JH) and 20-Hydroxyecdysone (20E). Therefore, it is important to understand the genetic regulation of silk production is thus a priority. JH binding protein (JHBP) transports JH from the hemolymph to target organs and cells and protects JH. In a previous study, we identified 41 genes containing a JHBP domain in the Bombyx mori genome. Only one JHBP gene, that is, BmJHBPd2, is highly expressed in the posterior silk gland (PSG) and its function remains unknown. In the present study, we investigated the expression levels of BmJHBPd2 and the major silk protein genes in the high silk-producing practical strain 872 (S872) and the low silk-producing local strain Dazao. Our results have shown that BmJHBPd2 was more highly expressed in S872, than in the Dazao strain, which is consistent with the expression pattern of fibroin genes. A subcellular localization assay indicated that BmJHBPd2 is located in the cytoplasm. In vitro hormone induction experiments showed that BmJHBPd2 was upregulated by treatment with juvenile hormone analogue (JHA). BmKr-h1 upregulation was significantly inhibited by overexpression of BmJHBPd2 at the cell level when induced by JHA. However, overexpression of BmJHBPd2 in the posterior silk gland by transgenic methods led to the inhibition of the expression of the silk fibroin gene, resulting in a reduction in silk yield. Further investigation has shown that in the BmJHBPd2OE individual, the key transcription factor Krüppel homolog 1 (Kr-h1) of the JH signaling pathway was inhibited, and 20E signaling pathway genes, such as broad complex (Brc), E74A, and ultraspiracle protein(USP), were upregulated. Our results have indicated that BmJHBPd2 plays an important role in the JH signaling pathway and was important for silk protein synthesis. Furthermore, our findings have helped to elucidate the mechanisms by which JH regulates silk protein synthesis.
ARTICLE | doi:10.20944/preprints202305.1040.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aleyrodidae; Aleurodicinae; parasitoid; biological control; New World
Online: 15 May 2023 (12:06:35 CEST)
The genus Dirphys Howard is synonymized with Encarsia Förster syn. n. and treated as a species-group of Encarsia, referred to henceforth as the Encarsia mexicana species-group. The monophyly of Encarsia is discussed in relation to Dirphys. The new synonymy is based on phylogenetic analyses of the nuclear ribosomal 28S-D2 gene region (43 taxa, 510 bp). The Encarsia mexicana species-group is recovered as strongly monophyletic within Encarsia. All species of the Encarsia mexicana species-group are revised. The group includes six previously described species, and fourteen newly described species. All species are described (or redescribed) and illustrated. Detailed distributional data, and, where available, plant associate and host records are provided for all species. Encarsia myartsevae Kresslein & Polaszek nom. nov. is here proposed as a replacement name for Encarsia mexicana Myartseva, now preoccupied by Encarsia mexicana (Howard). A dichotomous identification key, supplemented by an online multiple-entry key, is provided for all species.
ARTICLE | doi:10.20944/preprints202305.0964.v1
Subject: Biology And Life Sciences, Insect Science Keywords: red palm weevil; pest invasion; metamorphosis; gut microbiota; growth hormone; pupation nature
Online: 12 May 2023 (15:04:41 CEST)
Red palm weevils (RPWs) are a major pest to coconut and palm trees, causing significant economic losses in many countries. The current control method involves using insecticides, which are unsustainable and environmentally damaging. Thus, it is necessary to develop an eco-friendly and sustainable approach to mitigate the RPW problem. Our studies have revealed that feeding RPWs with food containing specific herbs can affect the weevils' mutualistic relationship with gut microbiota or their growth hormones, resulting in a notable reduction in the metamorphosis rate at the pupation stage. For instance, the addition of Kra-jeab (a roselle Hibiscus sabdariffa) and Kra-pao (a holy basil Ocimum tenuiflorum) led to a reduction of 76.7% and 75.6%, respectively, in the metamorphosis rate, while combining the two herbs resulted in a higher reduction rate of 86.7%. In addition to these findings, altering their pupation nature by reducing the fiber length used in RPW feed to less than 1 centimeter can stop the weevil’s pupation entirely. These findings demonstrate the potential application of biological and physical factors to reduce RPWs' metamorphosis rate and control their destructive impact on palm industries, thus providing a promising solution for the conflict between palm and insect farmers.
ARTICLE | doi:10.20944/preprints202305.0666.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Electrophysiology; Bee; Melipona; ECG; Restraint stress; anesthetic
Online: 9 May 2023 (14:30:31 CEST)
The hemodynamic activity of Melipona flavolineata workers was evaluated during restraint stress for a period of 30 minutes. The observed parameters were power variation in the elapsed time, and subsequently six periods of one second were divided and called: A, B, C, D, E and F; in each period the electrocardiographic parameters were evaluated: Heart rate, Amplitude, R-R Interval, Duration of QRS and Q-T interval. The experiment was carried out with 8 worker bees of M. flavolineata, for which electrodes with nickel-chromium alloy were made. The bees were previously anesthetized with isoflurane and properly contained and fixed in a base for stereotaxis in which the electrode was implanted. All these procedures were performed inside a Faraday cage. The results showed power oscillations during the recording with the highest energy level between 300 and 600 s. Heart rate, QRS amplitude and QRS duration parameters underwent changes recorded during the restraint stress period. However, for the Q-T interval there was no difference during the recordings. Thus, the cardiac activity of M. flavolineata can be used as a biomarker and being used to clarify physiological issues or alterations caused by toxic agents and indicate risk factors for these animals.
ARTICLE | doi:10.20944/preprints202305.0462.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Andrena camellia; genome; RNASeq; molecular evolution; gene expression; galactose derivatives; NAGA-like
Online: 8 May 2023 (08:08:31 CEST)
Oil-tea (Camellia oleifera) is a woody oil crop whose nectar includes galactose derivatives that are toxic to honey bees. Interestingly, some mining bees of the genus Andrena can entirely live on nectar (and pollen) of oil tea and are able to metabolize these galactose derivatives. We present the first next-generation genomes for five and one Andrena species that are respectively specialized and non-specialized oil-tea pollinators, and combining with published genomes of six other Andrena species which did not visit oil-tea, we performed molecular evolution analyses on genes involved in metabolism of galactose derivatives. Six genes (NAGA, NAGA-like, galM, galK, galT, and galE) involved in galactose derivatives metabolism were identified in the five oil-tea specialized species, but only five (with the exception of NAGA-like) were discovered in the other Andrena species. Molecular evolution analyses revealed that NAGA-like, galK and galT in oil-tea specialized species appeared under positive selection. RNASeq analyses showed that NAGA-like, galK, and galT were significantly up-regulated in the specialized pollinator A. camellia compared to the non-specialized pollinator A. chekiangensis. Our study demonstrated that the genes NAGA-like, galK, and galT had played an important role in the evolutionary adaptation of the oil-tea specialized Andrena species.
ARTICLE | doi:10.20944/preprints202305.0294.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Empoasca onukii Matsuda; EonuIR25a; plant volatiles; RNA interference; olfactory system
Online: 5 May 2023 (04:13:36 CEST)
Olfaction plays a crucial role in many important behavioral activities of insects, such as finding sexual partners, locating hosts, and selecting oviposition sites. Ionotropic receptors (IRs) play a central role in detecting chemosensory information from the environment and guiding insect behaviors and are potential target genes for pest control. Empoasca onukii Matsuda is a major pest of the tea plant Camellia sinensis (L.) O. Ktze, and seriously influences tea yields and quality. In this study, the ionotropic receptor gene EnouIR25a in E. onukii was cloned, and the expression pattern of EnouIR25a was detected in various tissues. Behavioral responses of E. onukii to volatile compounds emitted by tea plants were determined by the olfactometer bioassay and field trials. To further explore the function of EnouIR25a in olfactory recognition of compounds, RNAi (RNA interference) of EnouIR25a was carried out by ingestion of in vitro synthesized dsRNAs. The CDS length of EnouIR25a was 1266 bp and it encoded a 48.87 kD protein. EnouIR25a was enriched in the antennae of E. onukii. E. onukii were more significantly attracted by 1-phenylethanol at concentration of 100 µl/ml. Feeding with dsRNA-IR25a significantly downregulated the expression level of EonuIR25a, after 3 h of treatment, which disturbed the behavioral responses of E. onukii to 1-phenylethanol at concentration of 100µl/ml. The response rate of E. onukii to 1-phenylethanol was significantly decreased after dsRNA-IR25a treatment for 12 h. In summary, the ionotropic receptor gene EnouIR25a was highly expressed in the antennae of E. onukii and was involved in olfactory recognition of the tea plant volatile 1-phenylethanol. The present study may help us to use the ionotropic receptor gene as a target for the behavioral manipulation of E. onukii in the future.
ARTICLE | doi:10.20944/preprints202305.0213.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Noctuidae; transposable elements; genomic diversity; phylogeny; horizontal transfer TE (HTT) events
Online: 4 May 2023 (07:37:23 CEST)
Noctuidae is known to have high species diversity, although the genomic diversity of Noctuidae species have not been studied extensively. Investigation of transposable elements (TEs) in this family can improve our understanding on the genomic diversity of Noctuidae. In this study, we annotated and characterized genome-wide TEs in ten noctuid species belonging to seven genera. With multiple annotation pipelines, we constructed a consensus sequence library containing 1,038 –2,826 TE consensus. The genome content of TEs showed high variation in the ten Noctuidae genomes, ranging from 11.3% to 45.0%. The relatedness analysis indicated that the TE content, especially the content of LINEs and DNA transposons, are positively correlated with the genome size (r=0.86, p-value=0.001). We identified SINE/B2 as a lineage-specific subfamily in Trichoplusia ni, a species-specific expansion of LTR/Gypsy subfamily in Spodoptera exigua, and a recent expansion of SINE/5S subfamily in Busseola fusca. We further revealed that of the four TE classes, only LINEs showed phylogenetic signal with high confidence. We also examined how the expansion of TEs contributed to the evolution of noctuid genomes. Moreover, we identified a total of 56 horizontal transfer TE (HTT) events among the ten noctuid species and at least three HTT events between the nine Noctuidae species and 11 non-noctuid arthropods. One of HTT events caused by a Gypsy transposon might have caused the recent expansion of Gypsy subfamily in the S.exigua genome. By determining the TE content, dynamics, and HTT events in the Noctuidae genomes, our study emphasized that TE activities and HTT events had substantial impacts on the Noctuidae genome evolution.
ARTICLE | doi:10.20944/preprints202305.0208.v1
Subject: Biology And Life Sciences, Insect Science Keywords: arthropods; MALDI-TOF MS; duration of ethanol storing; species identification
Online: 4 May 2023 (07:17:52 CEST)
MALDI-TOF is now considered as a relevant tool for the identification of arthropods, including lice and fleas. However, the duration and conditions of storage, such as in ethanol, which is frequently used to preserve these both ectoparasites, could impede their classification. The purpose of the present study was to assess the stability of MS profiles from Pediculus humanus corporis lice and Ctenocephalides felis fleas preserved in alcohol from one to four years and kinetically submitted to MALDI-TOF MS. A total of 469 cephalothoraxes from lice (n=170) and fleas (n=299) were tested. The reproducibility of the MS profiles was estimated based on the log score values (LSVs) obtained for query profiles compared to the reference profiles included in the MS database. Only MS spectra from P. humanus corporis and Ct. felis stored in alcohol for less than one year were included in the reference MS database. Approximately 75% of MS spectra from lice (75.2%, 94/125) and fleas (74.4%, 122/164) specimens stored in alcohol during 12 to 48 months, queried against the reference MS database, obtained a relevant identification. An accurate analysis revealed a significant decrease in the proportion of identification for both species stored for more than 22 months in alcohol. It was hypothesized that incomplete drying was responsible of MS spectra variations. Then, 45 lice and 60 fleas were subjected to longer drying periods from 12 to 24 hours. The increase in the drying period improved the proportion of relevant identification for lice (95%) and fleas (80%). This study highlighted that a correct rate of identification by MS could be obtained for lice and fleas preserved in alcohol for up to four years, on the condition that the drying period was sufficiently long for accurate identification.
COMMUNICATION | doi:10.20944/preprints202305.0184.v1
Subject: Biology And Life Sciences, Insect Science Keywords: tetranychids; mite injury; bronzing; predatory mites; highbush blueberry, Florida
Online: 4 May 2023 (04:14:48 CEST)
Tetranychid outbreaks have been detected since 2016 in southern highbush blueberries (SHB); however, it was not until 2019 when the southern red mite (SRM), Oligonychus ilicis (Acari: Tetranychidae) was confirmed as the pest causing severe bronzing and stunting, in multiple Florida and Georgia commercial blueberry plantings. There is little known about the management of SRM in SHB and only three miticides (fenazaquin, fenpyroximate, and acequinocyl), have recently been registered for use in SHB between 2019 and 2020. Similarly, there is no knowledge regarding the existence of natural enemies of SRM in SHB. This is the first report of naturally occurring predatory mites (Amblyseius sp. and Neoseiulus ilicis) associated with SRM in SHB. Predatory mites were recorded in treated bushes after evaluating the performance of seven miticides used to manage SRM populations including spiromesifen, acequinocyl, sulfur, sulfur + molasses, bifenazate, fenpyroximate, and fenazaquin. Miticide efficacy was rated based on the number of SRM recorded on collected leaves and plant damage ratings using an arbitrary index (from 0= no bronzing to 4= 100% bronzing). Additionally, the presence or absence of predatory mites per sample was recorded. Fenpyroximate used as the standard miticide, significantly reduced mite numbers seven days after application, as well as acequinocyl and fenazaquin. Only plants treated with fenpyroximate or fenazaquin showed significantly less bronzing compared with the control plants. Overall, fenpyroximate and fenazaquin demonstrated the best performance for managing O. ilicis on SHB and safe to naturally occurring predatory mites. Lastly, the level of growers’ awareness regarding SRM was assessed using surveys in 2020 to design adequate educational materials available to the grower community.
ARTICLE | doi:10.20944/preprints202305.0127.v1
Subject: Biology And Life Sciences, Insect Science Keywords: ant community; disturbance ecology; forest ecology; insect outbreaks; natural disturbances
Online: 3 May 2023 (10:04:06 CEST)
Insect outbreaks are major drivers of natural disturbances in forest ecosystems. Outbreaks can have both direct and indirect effects on the composition of soil arthropod communities, through canopy opening, nutrient addition and predator-prey interactions. In this study, we aim to understand the effects of forest tent caterpillar (Malacosoma disstria; FTC) outbreaks on ant communities in both temperate and boreal forests in Canada. Using pitfall traps and Berlese funnels, we compared the ant communities as well as the surrounding arthropod communities between control and outbreak sites in boreal andboreal and temperate forests (in Québec, Canada). Using the Sørensen dissimilarity index, we determined the alpha and beta diversity of the ant community. Other arthropods collected in the traps were counted to evaluate the richness and abundance of potential prey for the ants and other potential predators of the FTC. We used an indicator species analysis to examine the species associated with sites defoliated by the outbreak. In the boreal forest, we found that FTC outbreaks caused decreases in species richness and increases in the evenness of ant communities in defoliated sites. In the boreal forest sites, species composition varied significantly between control and outbreak sites. This pattern was driven by the presence of other predators. We also saw no changes in beta diversity in the boreal forest but did see a significant decrease in the temperate forest between the outbreak sites and the control sites. A similar, but weaker pattern was observed in the temperate forest. Ant species in the boreal forest tended to exhibit a more marked preference for either control or previously defoliated sites than species in the temperate forest. Our study showed that disturbances like insect outbreaks can drive changes in the ant community. While we saw small effects of outbreaks, manipulation experiments using resource addition could help us validate the mechanisms behind these relationships.
BRIEF REPORT | doi:10.20944/preprints202305.0123.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aedes aegypti; pyrethroid resistance; kdr mutations; detoxification enzymes; 10ème arrondissement of Cotonou; Godomey-Togoudo; Benin West Africa
Online: 3 May 2023 (09:30:25 CEST)
Epidemics of arboviruses in general, and dengue fever, in particular, are an increasing threat in areas where Aedes (Ae.) aegypti is present. The effectiveness of chemical control of Ae. aegypti is threatened by the increasing frequency of insecticide resistance. The aim of this study was to determine the susceptibility status of Ae. aegypti to public health insecticides and assess the underlying mechanisms driving insecticide resistance. Ae. aegypti eggs were collected in two study sites in the vicinity of houses for two weeks using Gravid Aedes Traps (GATs). After rearing mosquitoes to adulthood, female Ae. aegypti were exposed to the diagnostic doses of permethrin, deltamethrin and bendiocarb, using Centers for Disease Control and Prevention (CDC) bottle bioassays. Unexposed, un-engorged female Ae. aegypti were tested individually for mixed-function oxidase (MFO), glutathione-S-transferase (GST) and esterase activity. Finally, allele-specific PCR (AS-PCR) was used to detect kdr mutations (F1534C, S989P and V1016G) in the voltage-gated sodium channel gene in insecticide-exposed Ae. aegypti. Most traps were oviposition positive; 93.2% and 97% of traps contained Ae. aegypti eggs in the 10ème arrondissement of Cotonou and in Godomey-Togoudo, respectively. Insecticide bioassays assays detected resistance to permethrin and deltamethrin in both study sites and complete susceptibility to bendiocarb. By comparison to the insecticide-susceptibility Rockefeller strain, field Ae. aegypti populations had significantly higher levels of GSTs and significantly lower levels of and esterases; there was no significant difference between levels of MFOs. AS-PCR genotyping revealed the presence of the three kdr mutations (F1534C, S989P and V1016G) at high frequencies; 80.9% (228/282) of Ae. aegypti tested had at least one mutation, while the simultaneous presence of all three kdr mutations was identified in 13 resistant individuals. Study findings demonstrated phenotypic pyrethroid resistance, the overexpression of key detoxification enzymes and the presence of several kdr mutations in Ae. aegypti populations, emphasizing the urgent need to implement vector control strategies, targeting arbovirus vector species in Benin.
ARTICLE | doi:10.20944/preprints202304.1201.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Insecta; pest control; ecotoxicology; behavior; biological products; germoplasm; essential oil; insecticide; necrophoresis
Online: 29 April 2023 (04:06:06 CEST)
Ants of the genus Solenopsis are important invasive pests in the world. Due to their high dispersion capacity, aggressive behavior and because they feed on various sources of vegetable and animal protein, these insects have caused serious damage to public health and agriculture. The control has usually been carried out through the use of organosynthetic insecticides. However, due to the ecological and environmental impacts caused by the use these products, more sustainable alternatives have been sought for their control. Faced with these problems and due to the scarcity of registered products for the control of these insects, we aimed with this study to synthesize and evaluate the anticidal potential of carvacrol derivatives. The lethal and sublethal effects caused by these derivatives were compared with the essential oil of Lippia gracilis (50.7% carvacrol) and with the base molecule — carvacrol. Carvacryl benzoate was the most toxic derivative to Solenopsis sp. with an LD50 of 3.20 g/ mg. This compound was about 2 and 7.6 times, more toxic than carvacrol at the doses needed to kill 50 and 90% of populations, respectively. The workers of Solenopsis sp. showed a rapid reduction in survival when exposed to carvacrol (LT50 = 8.43h) and carvacryl benzoate (LT50 = 8.87h). Insects treated with sublethal doses of the compounds did not show significant effects on self-cleaning, allogrooming and aggregation, with the exception of those treated with L. gracilis essential oil. The oil increased self-cleaning and reduced allogrooming and aggregation. Ants treated with carvacrol and carvacryl benzoate showed greater distance and speed when compared to the control. These compounds decreased meanders and angular velocity. When live workers were exposed to dead individuals at the LD90 of the compounds, carvacryl benzoate was the derivative that most reduced insects survival, due to horizontal transfer. These results show the potential of the carvacrol derivative — carvacryl benzoate — for the alternative management of ants of the genus Solenopsis sp.
ARTICLE | doi:10.20944/preprints202304.1040.v1
Subject: Biology And Life Sciences, Insect Science Keywords: honey bee; nosemosis; Nosema ceranae; Apis mellifera; entomopathogenic fungi; metabolite
Online: 27 April 2023 (04:43:22 CEST)
This study aimed to select the most effective metabolites for controlling honey bee nosemosis using culture extracts from 342 entomopathogenic fungi of 24 species from 18 genera. The germination inhibitory activity of the fungal culture extract against Nosema ceranae spores was evaluated using an in vitro germination assay method. Among 89 fungal culture extracts showing germination inhibitory activity of approximately 80% or more, 44 culture extracts that maintained their inhibitory activity even at a concentration of 1% were selected. Finally, the honey bee nosemosis inhibitory activity was evaluated using the cultured extracts of 5 fungal isolates having a Nosema inhibitory activity of approximately 60% or more even when the extract was removed after treatment. As a result, the proliferation of Nosema spores was reduced by all fungal culture extract treatments. However, only the treatment of the culture extracts from Paecilomyces marquandii 364 and Pochonia bulbillosa 60 showed a reduction in honey bee mortality due to nosemosis. In particular, the extracts of these two fungal isolates also increased the survival of honey bees.
ARTICLE | doi:10.20944/preprints202304.0768.v1
Subject: Biology And Life Sciences, Insect Science Keywords: biosecurity; temperature; photoperiod; phenology; pest risk analysis
Online: 23 April 2023 (04:37:26 CEST)
The apple leaf-curling midge, Dasineura mali Kieffer (Diptera: Cecidomyiidae), is an invasive pest of apple. To provide crucial information for its pest risk analysis, forecast and management, we investigated the effects of temperatures (5, 10, 15, 20 and 25°C) and daylengths (10, 11, 12, 13, 14 and 15 hrs) on its development and survival. The midge could not complete its development at 10°C or lower. After transferred from 20°C to 10°C, mature larvae could survive for about two months and develop to adults. Pupation and emergence rates were significantly higher at 20°C than at 10°C and 25°C. Daylength had no effect on these parameters. The low temperature threshold and thermal requirement to complete development from eggs to adults were 3.7°C and 627 degree-days, respectively. The midge had significantly lower thermal requirement for completion of its lifecycle at 20°C (614.5 degree-days) than at 15°C (650.1 degree-days) and 25°C (634.8 degree-days). The thermal model developed in this study provided accurate predictions of the number of D. mali generations and adult emergence time in each generation in different regions of New Zealand. We suggest that the model could be used to predict population dynamics of this pest in other parts of the world.
ARTICLE | doi:10.20944/preprints202304.0580.v1
Subject: Biology And Life Sciences, Insect Science Keywords: herbivore-induced plant defense; signaling pathway; intraguild predation; jasmonoyl-isoleucine; abscisic acid
Online: 19 April 2023 (09:31:48 CEST)
The fall armyworm (FAW), Spodoptera frugiperda, has become one of the most important pests on corn in China since it invaded in 2019. Although FAW has not been reported to cause widespread damage to rice plants in China, it has been sporadically found feeding in the field. If FAW infests rice in China, the fitness of other insect pests on rice may be influenced. However, how FAW and other insect pests on rice interact remains unknown. In this study, we found that the infestation of FAW larvae on rice plants prolonged the developmental duration of the brown planthopper (BPH, Nilaparvata lugens (Stål)) eggs, and plants damaged by gravid BPH females did not induce defenses that influenced the growth of FAW larvae. Moreover, co-infestation by FAW larvae on rice plants did not influence the attractiveness of volatiles emitted from BPH-infested plants to Anagrus nilaparvatae, an egg parasitoid of rice planthoppers. FAW larvae were able to prey on BPH eggs laid on rice plants and grew faster compared to those larvae that lacked available eggs. Studies revealed that the delay in development of BPH eggs on FAW-infested plants was probably related to the increase in levels of jasmonoyl-isoleucine, abscisic acid and the defensive compounds in the rice leaf sheaths on which BPH eggs were laid. These findings indicate that if FAW invades rice plants in China, the population density of BPH may be decreased by intraguild predation and induced plant defenses, whereas the population density of FAW may be increased.
ARTICLE | doi:10.20944/preprints202304.0067.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Weaver ant abundance; Intermediate workers caste; Major workers; Behaviours; Reproductive; Polymorphic workers
Online: 5 April 2023 (15:40:41 CEST)
The Asian weaver ant Oecophylla smaragdina is a natural enemy (predator) used as a biological control agent in Australia and several Southeast Asian nations against the most destructive and economically important oriental fruit fly Bactrocera dorsalis. For biological control of the invasive bagworm species Metisa plana in oil palm plantations, the composition of the colony's social structure was investigated to ensure its efficacy. On two colonies, all castes were examined stereo microscopically after nest collection and dissection. The head's width, head, thorax, abdomen, and body lengths of workers were evaluated during the morphology analysis. All colonies with more than a thousand eggs comprise of a founding egg-laying queen, reproductive winged green and newly emerged yellow queens, as well as adult drone males and workers. Future queens, males, and workers' pupae and larvae comprised immature individuals. It is the first study to characterise one caste of minor workers, two previously unidentified castes of intermediate workers, and two castes of major workers. The lengths of the body and abdomen are proposed as differentiating factors for workers. The discovery of a polymorphic size frequency distribution model contrasts with the consistently reported existence of archetypical bimodal systems in ants. Intermediate workers foraging outside the nest revealed reconnaissance and aggressive behaviours that aided major workers in their daily tasks. Due to their short lifespan and segregated nests, it is difficult to successfully sample adult males in wide plantations. An entire year's worth of reproductive individuals are produced by stable, three-year-old colonies, with a decrease in population size correlated with a significant decline in rainfall interception.
ARTICLE | doi:10.20944/preprints202303.0482.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Fall army worm; insect biology; life table; nutritional indices; host suitability
Online: 28 March 2023 (10:11:21 CEST)
Spodoptera frugiperda is a new invasive and highly polyphagous pest that attacks corn in Indonesia. The availability of abundant plant species allows pests to switch to other host plants to maintain their population. This research aims to examine the development, reproduction, nutritional indices, and life table of S. frugiperda in several plant species. The plants tested were corn, rice, broccoli, oil palm, and baby corn as controls. Ten individual insects were used and repeated five times for each plant species. The test results show that different types of plant feed affect the development time, imago life span, fecundity, and fertility of S. frugiperda. The types of plant feed, that were baby corn fruit and broccoli had higher net reproduction value (R0), intrinsic growth rate (r), gross reproduction rate (GRR), shorter mean generation period (T), and population doubling time (DT) than in corn and rice leaves. On oil palm leaf feed no population parameters can be determined because no larvae developed into adults and had the lowest nutritional indices parameters, so that could not be exploited as a host plant. Also, the nutritional indices of several feed plant species tested provided information that broccoli could be a suitable host when there was no corn in the field.
ARTICLE | doi:10.20944/preprints202303.0250.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Aedes aegypti; Musca domestica; house fly; toxicology; natural products; insecticide synergists
Online: 14 March 2023 (06:34:58 CET)
With widespread resistance to a limited number of insecticides available for medical and veterinary pests, new insecticides and insecticide synergists are desperately needed in this market space. We assessed the topical toxicity of carvone, menthone, and fenchone compared to permethrin and methomyl against the yellow fever mosquito, Aedes aegypti, and the house fly, Musca domestica. We also evaluated the synergistic potential of the monoterpenoids with permethrin and methomyl. Additionally, we assessed the acetylcholinesterase inhibitory potential of each monoterpenoid compared to methomyl. While all three monoterpenoids performed relatively poorly as topical insecticides (LD50 > 4000 ng/mg on M. domestica; > 6000 ng/mg on Ae. aegypti), they synergized both permethrin and methomyl as well as or better than piperonyl butoxide (PBO). Carvone and menthone yielded synergistic co-toxicity factors (23 and 29, respectively), which were each higher than PBO at 24 h. Acetylcholinesterase inhibition did not appear to explain the toxic or synergistic effects of the three monoterpenoids with IC50 values greater than 1 mM for all, compared to the 2.5 and 1.7 µM for methomyl on Aedes aegypti and Musca domestica, respectively. This study provides valuable monoterpenoid toxicity and synergism data on two pestiferous insects and highlights potential for these chemistries in future pest control formulations.
ARTICLE | doi:10.20944/preprints202303.0005.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Red wood ants (Formica rufa-group); tree age classes; West Eifel Volcanic Field; herbaceous layer; woodpecker cavities; clearings; re-inventory; climate change
Online: 1 March 2023 (02:57:20 CET)
We re-inventoried red wood ant nests (RWA) in 12 study sites (≈1281 ha) in the Westeifel Volcanic Field, Germany, in an area-wide and integrated ecosystem approach after 12 years. Combined with the re-identification of previously mapped nests using a photo database, this approach leads to more accurate nest counts in (re)inventories. A total increase of nests from 1144 (2009) to 1252 (2021), and a dramatic one for the Heidberg site by 52-fold (2009) and 85-fold (2021) compared to a 1984 inventory was observed, contrasting with earlier postulations of a decline in RWA. Early to medium mature (41-80 years) and mature (³81–140 years) spruce forests were the preferred habitat. Large increase in small nest sizes suggests an increase in new nest settlements also in clearings, despite climate-induced forest dieback over the past decade. A decline in biodiversity in the herbaceous layer was observed; highly proliferating blackberries had no negative impact on RWA nests. Monitoring of woodpecker cavities in RWA nests is suggested as an indirect indicator tool for evaluating populations in forests. Positive ground movement rates caused by the Eifel plume are suggested another factor favoring nest settlements. This study contributes to the urgent update of statistically valid data required to a) effectively substantiate the status-quo of RWA occurrences, b) protect RWA as ecosystem engineers, c) advance understanding of Geo-Bio-Interactions in the wake of climate change, and c) contribute to the German government's Insect Conservation Action Program.
ARTICLE | doi:10.20944/preprints202302.0217.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Nilaparvata lugens; pymetrozine; reproductive behavior; bioassay method; resistance monitoring
Online: 13 February 2023 (14:13:43 CET)
To explore the effects of pymetrozine on the reproductive behavior of N. lugens, we established a bioassay method to accurately evaluate the toxicity of pymetrozine in N. lugens and establish the level of pymetrozine resistance of N. lugens in the field. In this study, pymetrozine’s effects on the fecundity of N. lugens were evaluated using the topical application method and rice-seedling dipping method. Moreover, the resistance of N. lugens to pymetrozine in a pymetrozine-resistant strain (Pym-R) and two field populations (YZ21 and QS21) was determined using the rice-seedling dipping method and fecundity assay methods. The results showed that treatment of N. lugens third-instar nymphs with LC15, LC50, and LC85 doses of pymetrozine resulted in significantly reduced male fertility and female fecundity. In addition, N. lugens adults treated with pymetrozine using the rice-seedling dipping and topical application method also exhibited significantly in-hibited male courtship, fertility, and female receptivity. Using the rice-stem dipping method, pymetrozine resistance was shown to be at high levels in Pym-R (194.6-fold), YZ21 (205.9-fold), and QS21 (212.8-fold), with LC50 values of 522.520 mg/L (Pym-R), 552.962 mg/L (YZ21), and 571.315 (QS21) mg/L. However, when using the rice-seedling dipping or topical application fe-cundity assay method, Pym-R (EC50: 14.370 mg/L, RR=12.4-fold; ED50: 0.560 ng/adult, RR=10.8-fold), YZ21 (EC50: 12.890 mg/L, RR=11.2-fold; ED50: 0.280 ng/adult; RR=5.4-fold), and QS21 (EC50: 13.70 mg/L, RR=11.9-fold) exhibited moderate or low levels of resistance to pymet-rozine. Our studies show that pymetrozine can significantly inhibit the fecundity of N. lugens. The fecundity assay results showed that N. lugens only developed low to moderate levels of resistance to pymetrozine, indicating that pymetrozine can still achieve effective control on the next gen-eration of N. lugens populations.
ARTICLE | doi:10.20944/preprints202302.0159.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Trypanosomiasis; Tsetse fly; Trypanosoma brucie rhodesiense; Human; Animal; Ethiopia
Online: 9 February 2023 (08:45:48 CET)
Background: Sleeping Sickness, Human African Trypanosomiasis (HAT) is a vector- borne disease caused by Trypanosoma brucei (T.b). Sleeping sickness in Ethiopia was reported in 1967 for the first time. Recently in Southern parts of Ethiopia, in August 2022, five (5) cases of sleeping sickness (T. b. rhodesiense) were confirmed. Following this outbreak, the current investigation was aimed to identify the entomological and epidemiological drivers for the reemergence of HAT outbreak and recommend appropriate interventions.Methods: A cross sectional study design with descriptive data analysis was used. Tsetse fly collection and blood samples from cattle Animal were taken. NGU and bio-conical traps were used to determine the distribution (density and abundance) of the vector. About 10μl of blood was collected from the marginal ear vein of 301 cattle animals using the heparinized microhematocrit capillary. The parasite detection was carried out through vector dissection under binocular stereo-microscope (magnification of 60X) and microscopic examination from serum of Animals using the Buffy coat method. Results: A total of 329 tsetse flies were captured and identified to Glosina (G.) palidipes 259 (60.4%) and Glossina fuscipes 70 (16.3%). 188 (51.1%) of tsetse flies were collected from Dembagofa with 94 apparent density. Among all captured Tsetse fly, 39 (11.8%) of Tsetse were fed with high female apparent density in eachecological variation: wood land (51), Bush land (20) and grass land (11). Overall, the apparent density of tsetse fly was high in Wood land (93): G. pallidipes (76.5) and Bush land (36.5). Among all examine cattles for the presence of parasite, 9 cattles were detected positive with an overall prevalence of 3%. T. congolense 6 (2%) and T. vivax 1 (0.3%) with 2 (0.7%) suspected brucei. The parasite prevalence Trypanosoma was 4 (4.6%) in poor body a condition (Bcs) cattle. The animals in age range 5 - 9 years were infected high with 7 (5.3%) prevalence. Conclusion: The current study revealed that there are high-risk factors that predispose the community to Human African Trypanosomiasis (HAT) due to the presence of two different species of Tsetse flies and many animal reservoirs. The transmissions of Human African trypanosomiasis (HAT) are related to environmental, Vector, and human factors. Further geographically expanded investigation should be conducted throughout the country.
ARTICLE | doi:10.20944/preprints202302.0141.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Culex species; neotropical mosquito; French Guiana; MALDI-TOF MS; proteomic tool; arbovirus; monitoring
Online: 8 February 2023 (08:43:03 CET)
French Guiana mosquito fauna diversity encompasses 242 species, of which nearly half of them belong to Culex (Diptera: Culicidae) genus. Whereas several species from Culex genus are important vectors of arbovirus, scarce studies focus on Culex genus, notably due to the inaccurate morphological identification of field-caught females gender. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising method for the identification of mosquitoes. Culex females from French Guiana field were dissected based on morphological classification. Abdomens were used for molecular identification using COI (cytochrome oxydase 1) gene. Legs and thorax of 169 specimens belonging to 13 Culex species,( i.e. Cx. declarator, Cx. nigripalpus, Cx. quinquefasciatus, Cx. usquatus, Cx. adamesi, Cx. dunni, Cx. eastor, Cx. idottus, Cx. pedroi, Cx. phlogistus, Cx. portesi, Cx. rabanicolus and Cx. spissipes) were then submitted to MALDI-TOF MS analysis. A high intra-species reproducibility and inter-species specificity of MS spectra for each mosquito body part tested were noticed. A corroboration of the specimen identification was revealed between MALDI-TOF MS, morphological and molecular results. MALDI-TOF MS protein profiling proves to be a suitable tool for identification of neotropical Culex species and will permit to enhance knowledge on this highly diverse Culex mosquitoes genus.
ARTICLE | doi:10.20944/preprints202302.0029.v1
Subject: Biology And Life Sciences, Insect Science Keywords: hunting invasive locusts; food security; entomophagy; pest; entry of toxins into the food chain
Online: 2 February 2023 (04:35:05 CET)
Locust is a pest that attacks human and animal food and endangers national security by threatening food security. Spraying is the easiest and fastest way to deal with them. But the easiest way is not always the best way. With chemical resistance, not only will permanent immunity from locust attacks not arise, but they will also become resistant to poisons. While we have to pay billions of dollars annually for this strategy, we will also cause water and soil pollution. Therefore, the research results of other researchers were used and modeled to measure the possibility of hunting invasive locusts to investigate the possibility and benefits of this action. So, this study was conducted in the field method. The obtained results indicate that it is possible to hunt invasive locusts. If traps are placed on time and in the right place, the possibility of preserving crops after the pest attack increases by 2.3 times more in protected fields than in unprotected fields. By hunting locusts, fields and even pastures are preserved, poisons are prevented from entering the food chain and ecosystem, part of the economic loss of farmers affected by the invasion of locusts will be compensated, and by providing animal feed through hunting locusts, water consumption will be reduced, soil erosion and energy consumption are saved.
ARTICLE | doi:10.20944/preprints202302.0020.v1
Subject: Biology And Life Sciences, Insect Science Keywords: red flour beetle; Tribolium castaneum; pesticides; insecticides; resistance, metabolic
Online: 2 February 2023 (01:57:34 CET)
Information about molecular mechanism of pesticide resistance in the rust-red flour beetle, a major pest destroying grains and flour across Nigeria is grossly lacking, hindering evidence-based con-trol. Here, we identified to species level three populations of the red-flour beetle from Kano, Ni-geria, as Tribolium castaneum, and investigated the mechanism driving their insecticide resistance. IRAC susceptibility bioassays established high cypermethrin resistance, with LC50s of 4.35-5.46mg/ml in the three populations, NNFM, R/Zaki and Yankaba. High DDT and malathion resistance was observed in NNFM, with LC50s of 15.32- and 3.71mg/ml, respectively. High sus-ceptibility was observed towards dichlorvos in all three populations with LC50s of 0.17-0.35mg/ml, respectively. Synergist bioassay with piperonylbutoxide significantly restored cypermethrin sus-ceptibility, with mortality increasing almost threefold, from 24.8% obtained from 1.25mg/ml of cypermethrin, to 63.3% in synergised group (p=0.013), suggesting a preeminent role of P450s. The two major knockdown resistance (kdr) mutations, T929I and L1014F in the IIS4 and IIS6 fragments of voltage-gated sodium channel were not detected in both cypermethrin-alive and cyperme-thrin-dead beetles, suggesting lesser role of target-site insensitivity. These findings highlight the need to explore alternative control tools for this pest and/or explore incorporation of synergists, like piperonylbutoxide as additional chemistries into pesticides formulations to improve their ef-ficacy.
ARTICLE | doi:10.20944/preprints202301.0578.v1
Subject: Biology And Life Sciences, Insect Science Keywords: horse chestnut tree; diversity; population dynamics; mite density; city parks
Online: 31 January 2023 (08:45:45 CET)
Phytoseiidae inhabit a wide range of herbs, shrubs and trees. Aesculus hippocastanum is an important ornamental tree in Europe and is likely reservoir of these mites. We therefore assessed the species composition and the spatial and seasonal variability in the abundance of Phytoseiidae in city parks in South Bohemia, Czech Republic. Leaf samples were randomly collected from horse chestnut tree branches at eight sites, five times during the vegetation season in 2013. The mites were collected by washing technique and mounted on slides for identification. In total, 13,903 specimens of phytoseiid mites were found, and eight species were identified: Amblyseius andersoni, Euseius finlandicus, Kampimodromus aberrans, Neoseiulella tiliarum, Phytoseilus macropilis, Paraseiulus talbii, Paraseiulus triporus and Typhlodromus (Typhlodromus) pyri. Paraseiulus talbii and P. macropilis were recorded on the leaves of horse chestnut trees for the first time in the Czech Republic in this study. The predominant species was E. finlandicus (96.25%). The number of mites per compound leaf was, on average, 2.53, 10.40, 23.54, 11.59 and 9.27 on the sampling dates in each month between May and September, respectively. The mite density was significantly affected by the sampling site and date.
ARTICLE | doi:10.20944/preprints202301.0506.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Beetles; abundance; diversity; indicator species; Riyadh; species richness; urbanization; Wadi Hanifa
Online: 27 January 2023 (12:57:42 CET)
Urbanization affects all elements of the pre-urban environment, including soils, hydrology, vegetation, and microclimate. Recently, Saudi Arabia has experienced rapid urbanization and growth. Thus, the country's biodiversity has been threatened. In Riyadh, beetle assemblages were assessed along a rural-suburban-urban gradient. A total of 2,791 individuals from 94 species belonging to seven families were collected at 15 sites along three different gradients of urbanization in Wadi Hanifa. Tenebrionidae dominated abundance (60.1%) and richness (38%). Beetle abundance, evenness, and diversity were not different among habitats; however, species richness was higher in rural habitats. DCA and CCA analyses showed distinct differences among sites along gradients. Urbanization intensity, soil variables, and land cover were significantly correlated with DCA axis 1, while elevation and flora were significantly correlated with DCA axis 2. The most critical operating environmental variables in Wadi Hanifa were buildings, elevation, soil organic carbon, litter cover, and litter depth, as well as plants such as Launaea capitata, Lycium shawii, Alhagi graecorum, and Heliotropium currasavicum. Ten species in our study are associated with urban habitats, six with suburban habitats, and seven with rural habitats. Consequently, expanding urban areas may negatively affect the richness and composition of beetles and may result in the loss of some native species.
ARTICLE | doi:10.20944/preprints202212.0343.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Labidostomis lusitanica; Chrysomelidae; Pistacia vera; 2-isobutyl-3-methoxypyrazine; electroantennography; behavior
Online: 20 December 2022 (01:41:47 CET)
In spite of its incidence on pistachio trees, the chemical ecology of Labidostomis lusitanica (Germar) (Coleoptera: Chrysomelidae) has been neglected so far. In this work we provide the first evidence of a biologically active male-specific compound that may be promoting field aggregation. Headspace collections by solid-phase microextraction from feral males and females reported the presence of 2-isobutyl-3-methoxypyrazine exclusively on males. Electroantennographic recordings revealed that males and females responded in a dose-dependent manner to increasing stimuli of 2-isobutyl-3-methoxypyrazine, with females overall displaying a higher response than males. In dual-choice tests, both males and females showed a significant preference for the compound in comparison to a pure air stimulus. In the light of these results, the possible role of 2-isobutyl-3-methoxypyrazine as an aggregation cue in L. lusitanica is discussed.
ARTICLE | doi:10.20944/preprints202212.0249.v1
Subject: Biology And Life Sciences, Insect Science Keywords: tan; Drosophila; Drosophila guttifera; CRM; cis-regulatory; evo-devo; yellow; transcription factor; cis-regulatory module; cis-regulatory element
Online: 14 December 2022 (06:48:07 CET)
How complex morphological patterns form is an intriguing question in developmental biology. However, the mechanisms that generate complex patterns remain largely unknown. Here we sought to identify the genetic mechanisms that regulate the tan (t) gene in a multi-spotted pigmentation pattern on the abdomen and wings of Drosophila guttifera. Previously, we showed that yellow (y) gene expression completely prefigures the abdominal  and wing  pigment patterns of this species. In the current study, we demonstrate that the t gene is co-expressed with the y gene in nearly identical patterns, both transcripts foreshadowing the adult abdominal and wing melanin spot patterns. We identified cis-regulatory modules (CRMs) of t, one of which drives reporter expression in six longitudinal rows of spots on the developing pupal abdomen, while the second CRM activates the reporter gene in a spotted wing pattern. Comparing the abdominal spot CRMs of y and t, we found a similar composition of putative transcription factor binding sites that are thought to regulate the complex expression patterns of both terminal pigmentation genes y and t. In contrast, the y and t wing spots appear to be regulated by distinct upstream factors. Our results suggest that the D. guttifera abdominal and wing melanin spot patterns have been established through the co-regulation of y and t, shedding light on how complex morphological traits may be regulated through the parallel coordination of downstream target genes.
ARTICLE | doi:10.20944/preprints202211.0467.v1
Subject: Biology And Life Sciences, Insect Science Keywords: CYP6M2; CYP6P4; polymorphism; metabolic resistance; pyrethroid; Anopheles coluzzii; Anopheles gambiae
Online: 25 November 2022 (05:51:07 CET)
Assessing the genetic diversity of metabolic resistance genes such as cytochrome P450s helps to understand the dynamics and evolution of resistance in the field. Here, we analysed the polymor-phisms of CYP6M2 and CYP6P4 associated with pyrethroid resistance in Anopheles coluzzii and An. gambiae, to detect potential resistance markers. Field-caught resistant mosquitoes and susceptible lab-strains were crossed and F4 was exposed to permethrin for 15min and 90min to discriminate highly susceptible (HS) and highly resistant (HR) mosquitoes respectively. Significant permethrin mortality reduction was observed after pre-exposure to PBO, suggesting P450s genes involvement. QPCR analysis revealed significant over-expression of CYP6M2 (FC=19.57 [95%CI 13.96-25.18] for An. coluzzii; 10.16 [7.86-12.46] for An. gambiae) and CYP6P4 (FC=6.73 [6.15-7.30] An. coluzzii; 23.62 [26.48-20.76] An. gambiae). Full-gene and ≈1kb upstream were sequenced. For CYP6M2, upstream region shows low diversity in HR and HS (overall Hd=0.49, π=0.018), whereas the full-gene shows allelic-variation but without evidence of ongoing selection. CYP6P4 upstream region showed a lower diversity in HR (Hd=0.48) than HS (Hd=0.86) of An. gambiae. These results highlighted that CYP6P4-associated resistance is potentially driven by modification in upstream region. However further work is needed to determine the real causative variants which will help design rapid detec-tion tools.
REVIEW | doi:10.20944/preprints202211.0385.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Oecophylla genus; population abundance; territorial foragers; quarantine defoliators; IPM
Online: 21 November 2022 (08:31:55 CET)
The bagworms Metisa plana is a recurrent indigenous invasive defoliator in oil palm plantations. A moderate foliar injury can cost up to 40% and above of yield loss for years. As an effective biological control agent (BCA) or by integrated pest management (IPM) on insect pests of economic significance affecting major crops of the countries in Asia-Pacific region, the adoption of the Asian weaver ant Oecophylla smaragdina might support farmers facing outbreaks. Information about the foraging activity and population dynamic (PD) of Oecophylla are important in implementing such program. Oecophylla being an obligate arboreal by nature was observed spending extended periods on the ground by occupying a vast territory under constant surveillance mode, which is significant and valuable feature for pest control. The foraging activity of major workers, their exploratory venture is closely related to systematic predation-hunting activity. The scarcity of population dynamic studies on the Oecophylla species contrast with the reports frequency of subterranean species. Estimation of population density of Oecophylla by direct nest counting method is feasible, practical and sustainable. This is contrasting with calculation done on excavated underground colonies consequential of their extinction. Simulation inaccuracy due to insufficient experimental evidence from using exclusively mathematical models is giving to real time long term field population dynamic more importance. Oecophylla colonies' stability, forager abundance and permanent patrol hunting oriented activity, are key factors for pest reduction. If the evaluation on O. smaragdina is higher, for this last decade, a significant upsurge of study on O. longinoda provided substantial novel highlights. The introduction of Oecophylla may alleviate pests management cost and offers a healthier environment by stopping the harmful usage of broad spectrum contact pesticides.
ARTICLE | doi:10.20944/preprints202211.0203.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Tungiasis; Tunga penetrans; molecular entomology; DNA isolation; Phusion® polymerase; FIREpol® Taq polymerase; low-cost PCR,
Online: 10 November 2022 (11:19:42 CET)
Tungiasis is a neglected tropical disease caused by skin-penetrating female Tunga penetrans fleas. Although tungiasis causes severe health problems, its ecology is poorly understood and morphological descriptions of larvae are unavailable. To identify T. penetrans immature stages and sites where they develop, diagnostic PCRs are required. However, flea larvae feed on soil organic matter rich in PCR inhibitors. Here, three DNA preparation methods, a soil DNA kit removing inhibitors, a simple ammonium acetate precipitation approach (AmAcet) and a crude lysate of larvae (CL), were combined with amplification by the highly processive FIREPol® Taq or the inhibitor-resistant Phusion® polymerase. Independent of the polymerase used, frequency of successful amplification, Cq values and PCR efficacies for the low-cost CL and AmAcet methods were superior to the commercial kit for amplification of a 278 bp partial internal transcribed spacer-2 (ITS-2) and a 730 bp pan-Siphonaptera cytochrome oxidase I PCR. For the CL method combined with Phusion® polymerase, costs were approximately 20-fold lower than for methods based on the soil DNA kit, which is a considerable advantage in resource-poor settings. The ITS-2 PCR did not amplify Ctenocephalides felis genomic or Tunga trimammilata ITS-2 plasmid DNA allowing it to be used to specifically identify T. penetrans.
ARTICLE | doi:10.20944/preprints202210.0279.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Traps; beetles; monitoring; surveys; spatial distribution
Online: 19 October 2022 (10:07:04 CEST)
Monitoring is an important component of pest management, to prevent or mitigate outbreaks of native pests, and to check for quarantine organisms. Surveys often rely on trapping, especially when the target species respond to semiochemicals. Many traps are available for this purpose, but they are bulky in most cases, which raises transportation and deployment issues, and they are expensive, which limits the size and accuracy of any network. To overpass these difficulties, entomologists have used recycled material, such as modified plastic bottles, producing cheap and reliable traps but at the cost of recurrent handywork, not necessarily possible for all end-users (e.g., for national plant protection organizations). These bottle-traps have allowed very large surveys which would have been impossible with standard commercial traps, and we illustrate this approach with a few examples. Here we present, under a Creative Commons BY-SA License, the blueprint of a fan-trap, a foldable model, laser-cut from a sheet of polypropylene, that can rapidly be produced in large numbers, and could be transported and deployed in the field with very little efforts. Our first field comparisons show that fan-traps are as efficient as bottle-traps, and we describe two cases where they are being used for monitoring.
ARTICLE | doi:10.20944/preprints202210.0185.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Diurnal mosquitoes; Kairomones, Canopy stratum, Brazilian savanna
Online: 13 October 2022 (03:20:46 CEST)
The hand-net is the standard method for capturing mosquitoes with sylvatic diurnal activity in disease outbreaks in Brazil. However, occupational risks and biases related to the collectors´ abilities and attractiveness are important limitations. In this study, we compared hand-nets with automatic traps (CDC) associated to CO2 and BG-Lure®, in the Vassununga State Park, a Brazilian Savanna protection area. The collections carried out over 27 days, on the ground and the forest canopy. A total of 1,555 mosquitoes were obtained in 20 taxa. The diversity index ranged between 1.12 and 1.79 and the dominance index, from 0.22 to 0.40. The dominant species in the ground was Aedes scapularis (46.0%) and in the canopy, Hg. janthinomys/capricornii (31.9%). Haemagogus leucocelaenus was rare (n=2). The hand-net resulted in the greatest diversity and abundance of species in both strata, followed by traps associated with CO2. A low degree of similarity was observed between the hand-net on the ground compared to the other capture methods. The use of BG-Lure® alone resulted in a low number of specimens. In conclusion, the hand-net is still the method of choice for collecting arbovirus vectors in the diurnal period, especially yellow fever vectors.
REVIEW | doi:10.20944/preprints202209.0454.v1
Subject: Biology And Life Sciences, Insect Science Keywords: CRISPR-Cas technology; pest management; plant stress resistance; insect resistance
Online: 29 September 2022 (07:08:41 CEST)
Global crop yield and food security are being threatened by phytophagous insects. Innovative methods are required to increase agricultural output while reducing reliance on hazardous synthetic insecticides. It appears to be quite effective at reducing production costs and boosting farm profitability to use the ground-breaking CRISPR-Cas technology to create plants that are insect resistant. In contrast, this new technique can modify an insect's genome to either produce gene drive or get beyond an insect's tolerance to various insecticides. This paper reviews and critically discusses the use of CRISPR-Cas genome editing technology in long-term insect pest management. The emphasis of this review is on the prospective uses of the CRISPR-Cas system for insect stress management in crop production by creating genome-edited crops and insects. The potential and difficulties of using CRISPR-Cas technology to reduce pest stress in crop plants are critically examined and discussed.
ARTICLE | doi:10.20944/preprints202209.0434.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Apis cerana; A. c. koreana; population; gene vitellogenin; genetic structure; nucleotide polymorphism; adaptation
Online: 28 September 2022 (09:02:03 CEST)
Apis cerana and Apis mellifera, are very important honey species for agriculture in Asian countries. In recent decades, A. cerana populations have sharply declined in all Asian countries as a result of Sacbrood Virus infection and have now recovered to their original size. It can change the genetic structure of local populations of A. cerana. We used the nuclear gene Vitellogenin VG to assess the genetic structure of local populations of A. cerana and the signature of adaptive selection. We performed a population genetic analysis of the honey bees A. cerana from South Korea in comparison with A. cerana samples from Russia, Japan, Nepal, and China. The sequences of the gene VG of a closely related honey bee species, A. mellifera, from India and Poland were used as outgroup samples. A comparative analysis of northern and southern A. cerana populations was performed. The signatures of positive adaptive selection were found in the local population of A. cerana. We performed the Tajima's neutrality D test for A. cerana populations from different local populations based on the gene VG exon sequences. All A. cerana populations showed signs of population size expansion following the possible recent decline in population sizes. The local populations of A. c. koreana were subdivided according to their geographical distribution into southern, northern, and central Korean clusters. The gene VG exon sequences can be used as informative markers for monitoring the changes in genetic structure and adaptation to the environment processes in A. cerana populations.
ARTICLE | doi:10.20944/preprints202209.0236.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Insect Biotechnology; molecular entomology; pest management; Sterile Insect Technique; sperm storage; transgenesis; Tribolium castaneum
Online: 16 September 2022 (03:02:52 CEST)
Sperm marking represents a valuable monitoring tool for genetic pest control strategies such as the Sterile Insect Technique, but also provides a key tool for reproductive biology studies. Sperm-marked lines can be generated by introducing transgenes that mediate the expression of fluorescent proteins during spermatogenesis. Homozygous lines established by transgenesis approaches are going through a genetic bottleneck that can lead to reduced fitness. Transgenic SIT approaches have mostly focused on Dipteran and Lepidopteran pests so far. With this study, we provide sperm-marked lines for the Coleopteran pest model organism, the red flour beetle Tribolium castaneum, based on the β2-tubulin promoter/enhancer driving red (DsRed) or green (EGFP) fluorescence. The obtained lines are reasonably competitive and were thus used for studies on reproductive biology confriming the phenomenon of ‘last male sperm precedence’ and that the spermathecae are deployed for long term sperm storage enabling the use of sperm from first matings even after secondary matings for a long period of time. The homozygosity and competiveness of the lines will enable future studies to analyze the controlled process of sperm movement into the long time storage organ as part of a post-mating cryptic female choice mechanism of this extremely promiscuous species.
ARTICLE | doi:10.20944/preprints202208.0525.v1
Subject: Biology And Life Sciences, Insect Science Keywords: new species; Biogeography; Mediterranean; Red List; Bioacoustics
Online: 30 August 2022 (14:38:12 CEST)
In late April 2022, during the hearing of the audio files from an unsupervised bioacoustic assessment of the shearwater populations (Aves, Procellariiformes) on the coast of Pantelleria island (Italy, Sicily), a cricket song of unknown attribution was heard. The first bioacoustic analyses, including FFT-based spectrograms and sound pressure envelopes, confirmed that it could not be attributed to the known sound of any Italian nor Mediterranean species of cricket. In the ensuing weeks, field research made on purpose in the original station and in further localities in the southern coast of Pantelleria provided photographs, living specimens and further audio records. As soon as the photos were shared among the authors, it became clear that the species belonged to the genus Acheta. Further bioacoustic analyses and morphological comparison with type specimens of Mediterranean and North-African congenerics in relevant collections and in the scientific literature were conducted: they confirmed that the findings could only be attributed to a still undescribed species, that escaped detection due to its impervious and unfrequented habitat. Acheta pantescus n. sp. is apparently restricted to the effusive coastal cliffs of the island of Pantelleria, a habitat whose scant extension and vulnerability require environmental protection actions such as the inclusion in a special Red List by the IUCN Italian Committee.
ARTICLE | doi:10.20944/preprints202208.0465.v1
Subject: Biology And Life Sciences, Insect Science Keywords: insect; leaf miner; Coffea; pest control; biopesticide; silencing
Online: 29 August 2022 (04:27:45 CEST)
Background, Leucoptera coffeella (Guerin-Meneville, 1842) is a moth species (Lyonetiidae, Lepidoptera) pest that causes severe losses to coffee crops. Further information about its genomic data is required to allow molecular strategies for the development of sustainable pesticides and to gain in-depth knowledge on phylogenetics. However, the closest complete genome available is within the superfamily level (Yponomeutoidea). Here we report the generation of the first long-read genome, transcriptome and proteome results of L. coffeella and the in silico analysis performed in these molecular levels to investigate genes involved in the siRNA processing. Results, PACBio and paired-end Illumina combined DNA sequencing from pupae samples resulted in more than 436 Gb subreads and 31Mb reads with N50 read length of 15,512 nt, mean read length 13.8 Kb and max read length 420.7 Kb. Additionally, 20Gb data of short DNA sequencing was combined to produce 1,984 contigs comprising 397 Mb in total. The longest and shortest scaffold sizes are 10,809,567 nt and 15,247 nt, respectively (mean size 200,178 nt). The N50 scaffold was 275,598 nt and the GC content was 36.10%. Predicted coding DNA sequences counted 39.930 gene models. Searching of 5286 BUSCO groups revealed 91.7 percent of completeness (single and duplicated genes combined) compared to lepidoptera genomes (lepidoptera_odb10). Flow cytometry showed the 1C DNA content is approximately 295 Mb. RNA-Seq from seven development stages resulted in 28294 identified transcripts. Additionally, proteomics from immature stages resulted in 2045 proteins matching the gene models. Conclusions, This first nuclear genome of the Lyonetiidae family brings valuable molecular resources to study Lepidoptera genomes. Genome, transcriptome and proteome sequencing to raise genome annotation precision may resolve uncovered taxonomic issues. In addition, these combined approaches provide insights into plant-insect interaction players, as horizontally transferred genes (HGT) and endosymbionts. Put together, the generated data enables the development of molecular tools towards sustainable biotechnology solutions for lepidopteran pest control.
ARTICLE | doi:10.20944/preprints202208.0359.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Dengue Fever; Arbovirus; Aedes aegypti; Ethiopia; Climate
Online: 19 August 2022 (05:52:42 CEST)
Dengue Fever (DF) is an important arthropod-borne viral infection, which has repeatedly oc-curred as outbreaks in eastern and northeastern Ethiopia since 2013. A cross-sectional epidemio-logical outbreak investigation was carried out from September - November 2019 on febrile pa-tients (confirmed malaria negative) who presented with suspected and confirmed DF at both public and private health facilities in Gewane District, Afar Region, northeastern Ethiopia. Ento-mological investigation of containers found in randomly selected houses belonging to DF positive patients was undertaken, to survey for the presence of Aedes larvae or pupae. A total of 1185 DF cases was recorded from six heath facilities during the 3-month study period. The mean age of DF cases was 27.2 years and 42.7% of the cases were female. The most affected age group was 15-49 years (78.98%). However, the attack rate (AR) was highest in the 49+ age group (134.2). A total of 162 artificial containers were inspected from 62 houses, with 49.4% found positive for Aedes larva/pupae. Aedes mosquitoes were mostly found breeding in buckets/bowls, clay jars, plastic tanks, and tires. World Health Organization entomological indices classified the study site as high risk for dengue outbreaks (House Index=45.2%, Container Index=49.4% and Breteau In-dex=129). Study findings highlight the importance of vector control to prevent future dengue out-breaks in the region. The scarcity of drinking water and changing climactic conditions may have also contributed to the occurrence of this outbreak.
ARTICLE | doi:10.20944/preprints202206.0364.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Anoplophora glabripennis; Dastarcus helophoroides; Dendrocopos major; MaxEnt; climate change; natural enemy; pest management
Online: 27 June 2022 (11:01:09 CEST)
The Asian longhorned beetle (ALB), Anoplophora glabripennis is a forestry pest found worldwide. ALB causes serious harm because of the lack of natural enemies in the invaded areas. Dastarcus helophoroides and Dendrocopos major are important natural enemies of ALB. MaxEnt was used to simulate the distribution of D. helophoroides and D. major in China and Xinjiang, and their suitable areas were superimposed to evaluate the pest control ability of D. helophoroides and D. major. The results showed that, with climate change, the suitable areas of D. helophoroides and D. major migrated northward; the centroid shift of ALB was greater than that of D. helophoroides and D. major, which would lead to fewer natural enemies encountered by ALB during migration, reduce the control ability of natural enemies, and increase the risk of disastrous outbreaks in the invaded areas. We found that the damage caused by ALB was not serious in the areas with natural enemies and very serious in the areas without natural enemies. We suggest that natural enemies should be included in the model used for predicting suitable areas for invasive pests, as this is more conducive to assessing the risks of invasive organisms to the local ecological environment.
ARTICLE | doi:10.20944/preprints202205.0315.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Culex pipiens biotypes pipiens / molestus; hybrids; disease vectors; DNA-based identification; cyto-chrome c oxidase I (COI); fragment size analyses (ACE2, CQ11)
Online: 24 May 2022 (03:48:37 CEST)
This survey reports on the DNA identification and occurrence of Culex torrentium and Cx. pipiens s.s. in Belgium. These native disease vector mosquito species are morphologically difficult to separate and the biotypes of Cx. pipiens s.s. are morphologically indistinguishable. Culex torrentium and Cx. pipiens s.s. were identified using the COI and ACE2 loci. We recorded 1,248 Cx. pipiens s.s. and 401 Cx. torrentium specimens from 24 locations in Belgium (collected between 2017 and 2019). Culex pipiens biotypes pipiens and molestus, and their hybrids, were differentiated by fragment size analysis of the CQ11 locus (956 pipiens and 227 molestus biotype specimens, 29 hybrids). Hybrids were observed at 13 out of 16 sympatric sites. These results confirm that both species are widespread in Belgium, but while Cx. torrentium revealed many COI haplotypes, Cx. pipiens s.s. showed only one abundant haplotype. This latter observation may either reflect a recent population-wide demographic or range expansion, or a recent bottleneck, possibly linked to a Wolbachia infection. Finally, new evidence is provided for the asymmetric but limited introgression of the molestus biotype into the pipiens biotype.
ARTICLE | doi:10.20944/preprints202204.0206.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Anopheles arabiensis; Blood meal index; Boreda district; Morphological misclassification
Online: 21 April 2022 (10:55:23 CEST)
There are a number of Anopheles species playing either primary or secondary roles in malaria transmission. Hence, understanding the species composition, their bionomics, and behaviors are all important in designing and implementing vector control intervention tools. Moreover, accurate identification of different species is vital. This study aimed to assess species composition, sporozoite infection rate, and blood meal origins of malaria mosquitoes in two malaria-endemic villages of Boreda district in Gamo zone, southwest Ethiopia. Thirty houses, 20 for Centers for Disease Control and Prevention (CDC) light traps and 10 for Pyrethrum Spray Catches (PSC), were randomly selected for bimonthly mosquito collection from October 2019 to February 2020. Enzyme-linked-immunosorbent assay (ELISA) test was done to detect the blood meal origins and circumsporozoite proteins (CSPs). The entomological inoculation rate (EIR) was calculated by multiplying the sporozoite and human biting rates from PSCs. Anopheles gambiae and An. funestus complexes were further identified into species by polymerase chain reaction (PCR). Anopheles species with some morphological structures confusing with An. gambiae or An. funestus complexes were father confirmed by PCR. A total of 15 Anopheles species were documented, of which An. demeilloni was the dominant one. Only An. arabiensis was positive for P. falciparum CSP. The overall P. falciparum CSP rate of An. arabiensis was 0.54%. The overall estimated P. falciparum EIR of An. arabiensis from PSC was 1.5 infectious bites/person/five months. Of the 145 freshly fed Anopheles mosquitoes tested for blood meal source, 57.9% (84/145) had bovine blood meal, 22 (15.2%) had human blood meal origin alone and 24 (16.5%) had mixed blood meal origins of human and bovine. An. demeilloni mainly fed on bovine blood (102/126 = 80.9%). Among 420 morphologically classified An. demeilloni, 11 (2.6%) were confirmed as An. lessoni (one of the An. funestus complexes) by PCR. A substantial number of morphologically classified An. salbaii, An. maculipalpis and An. fuscivenosus were found to be An. arabiensis by PCR. Regardless of the high diversity of Anopheles mosquitoes, An. arabiensis is playing the primary role in malaria transmission. Morphological misclassification of species could be a challenge in malaria mosquito monitoring and surveillance, and hence it should be supported by more sensitive techniques for confirmation.
ARTICLE | doi:10.20944/preprints202204.0039.v1
Subject: Biology And Life Sciences, Insect Science Keywords: horizontal transfer; Rhus gall aphids; Mariner transposable elements
Online: 7 April 2022 (02:31:25 CEST)
Horizontal transfer of transposons (HTT) is an important source of genomic evolution in eukaryotes. The HTT dynamics is well characterized in eukaryotes including insects however, but there is a huge gap of knowledge about HTT regarding many eukaryotes’ species. In this study we analyzed the events of the HTT between Rhus gall aphids (Hemiptera) and other insects. We analyzed the Mariner-like transposable elements (MLEs) belongs to Rhus gall aphids for the possible HT events. The MLEs have patchy distribution and have high similarity over the entire length of element with insects MLEs from different orders. We selected representative sequences from the Rhus gall MLEs and identified five events of HT between MLEs of Rhus gall aphids and other insects from five different orders. We also found multiple HTT events among the MLEs of insects from the five orders which demonstrate that these Mariner elements have been involved in recurrent HT between these six order of insects. Our current study closed the knowledge gap of HTT and reported the events between Rhus gall aphids and other insects for the first time. We believe that this study about HTT events will help to understand the evolution and spread of transposable elements in the genomes of Rhus gall aphids.
ARTICLE | doi:10.20944/preprints202203.0380.v1
Subject: Biology And Life Sciences, Insect Science Keywords: Exercise training; arrhythmias; Drosophila; apolipoprotein B; aging
Online: 29 March 2022 (10:07:13 CEST)
Cardiovascular disease (CVD) places a heavy burden on older patients and the global healthcare system. A large body of evidence suggests that exercise training is essential in preventing and treating cardiovascular disease, but the underlying mechanisms are not well understood. Here, we used the Drosophila melanogaster animal model to study the effects of early-life exercise training (ELET) on the aging heart and lifespan. We found in flies that age-induced arrhythmias are conserved across different genetic backgrounds. The fat body is the primary source of circulating lipoproteins in flies. Inhibition of fat body apoLpp (the flies apoB homolog) demonstrated that low expression of apoLpp reduced the development of arrhythmias in aged flies but did not affect average lifespan. At the same time, ELET can also reduce the expression of apoLpp mRNA in aged flies and have a protective effect on the heart, which is similar to the inhibition of apoLpp mRNA. Although treatment of apoLppRNAi and ELET alone had no significant effect on lifespan, the combination of apoLppRNAi and ELET extended the average lifespan of flies. Therefore, we conclude that apoLppRNAi and ELET are sufficient to resist age-induced arrhythmias, which may be related to the decreased expression of apoLpp mRNA, and that apoLppRNAi and ELET have a combined effect on prolonging the average lifespan.
ARTICLE | doi:10.20944/preprints202203.0350.v1
Subject: Biology And Life Sciences, Insect Science Keywords: insecticide resistance; resistance monitoring; method validation; WHO tube
Online: 25 March 2022 (15:40:56 CET)
Accurately monitoring insecticide resistance in target mosquito populations is important to combating malaria and other vector-borne diseases, and robust methods are key. The “WHO susceptibility bioassay” has been used for +60 years: mosquitoes of known physiological status are exposed to a discriminating concentration of insecticide. Several changes to the test procedures have been made historically which may seem minor but could impact bioassay results. The published test procedures and literature for this method were reviewed for methodological details. Areas where there was room for interpretation in the test procedures or where the test procedures were not being followed were assessed experimentally for impact on bioassay results: covering or uncovering of the tube end during exposure, number of mosquitoes per test unit, and mosquito age. Many publications do not cite the most recent test procedures, methodological details are reported which contradict the test procedures referenced or methodological details are not fully reported. As a result, the precise methodology is unclear. Experimental testing showed that using fewer than the recommended 15-30 mosquitoes per test unit significantly reduced mortality, covering the exposure tube had no effect, and using mosquitoes older than 2-5 days old increased mortality, particularly in the resistant strain. Recommendations are made for better reporting of experimental parameters.
ARTICLE | doi:10.20944/preprints202203.0345.v1
Subject: Biology And Life Sciences, Insect Science Keywords: insecticide-treated nets (ITN); pyrethroid; mosquito; strain characterisation; insecticide resistance; method development; durability monitoring; product evaluation; quality control (QC); dual active ingredients (dual-AI); bioefficacy
Online: 25 March 2022 (14:12:38 CET)
Durability monitoring of insecticide-treated nets (ITNs) containing a pyrethroid in combination with a second active ingredient (AI) must be adapted so that the insecticidal bioefficacy of each AI can be monitored independently. An effective way to do this is to measure rapid knock down of a pyrethroid-susceptible strain of mosquitoes to assess the bioefficacy of the pyrethroid component and to use a pyrethroid-resistant strain to measure the bioefficacy of the second ingredient. To allow robust comparison of results across tests within and between test facilities, and over time, protocols for bioefficacy testing must include either characterisation of the resistant strain, standardisation of the mosquitoes used for bioassays, or a combination of the two. Through a series of virtual meetings, key stakeholders and practitioners explored different approaches to achieving these goals. Via an iterative process we decided on the preferred approach and produced a protocol consisting of characterising mosquitoes used for bioefficacy testing before and after a round of bioassays, for example at each time point in a durability monitoring study. We present the final protocol and justify our approach to establishing a standard methodology for durability monitoring of ITNs containing pyrethroid and a second AI.
ARTICLE | doi:10.20944/preprints202203.0192.v1
Subject: Biology And Life Sciences, Insect Science Keywords: genetic differentiation; leaf beetle; mitochondrial DNA; microsatellites; haplotype; gene flow
Online: 14 March 2022 (16:48:57 CET)
leaf beetle (BLB) (Ootheca mutabilis) has emerged as an important bean pest in Uganda, leading to devastating crop losses. There is limited information on the population genetic structure of BLB despite their importance. In this study, novel microsatellite markers and the partial mitochondrial cytochrome oxidase subunit I (mtCOI) gene sequences were used to analyze the spatial population genetic structure, genetic differentiation, gene flow and haplotype diversity of 87 O. mutabilis samples from five populations. We identified 19,356 simple sequence repeats (SSRs) (mono, di, tri, tetra, penta, and hexa-nucleotides) of which 81 di, tri and tetra-nucleotides were selected for primer synthesis. Five highly polymorphic SSR markers (4-21 alleles, heterozygosi-ty 0.59-0.84, polymorphic information content (PIC) 50.13-83.14%) were used for this study. Analyses of the five O. mutabilis populations with these five novel SSRs found 89% of genetic variation occurring within individuals, 9% among individuals and 2% among populations. Genetic differentiation was low but significant for SSR and insignificant for mtCOI partial sequence data while gene flow was high across the populations. There was no evidence of isolation by distance between geographical and genetic distances. Bayesian clustering identified signature of admixture that suggests genetic contributions from two ancestral genetic lineages, and the median-joining haplotype network showed low differentiation of many different haplotypes from the most common haplotype. Low genetic differentiation and high gene flow indicates unrestricted migrations between populations. This information will contribute to the design of BLB control strategies.