ARTICLE | doi:10.20944/preprints202302.0020.v1
Subject: Biology, Entomology 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, Entomology 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, Entomology 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, Entomology 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, Entomology 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, Entomology 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, Entomology 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, Entomology 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
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, Entomology 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, Entomology 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, Entomology 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, Entomology 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/preprints202208.0465.v1
Subject: Biology, Entomology 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
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, Entomology 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, Entomology 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, Entomology 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, Entomology 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, Entomology 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, Entomology 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, Entomology 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, Entomology 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.
ARTICLE | doi:10.20944/preprints202202.0232.v1
Subject: Biology, Entomology Keywords: Small RNA sequencing; miRNAs; Target prediction; Chemosensory-associated genes; Apolygus lucorum
Online: 18 February 2022 (10:01:58 CET)
MicroRNAs (miRNAs) are a class of small non-coding RNAs, which function as regulators of gene expression and contribute in numerous physiological processes. However, little is known referring to miRNAs function in insect chemosensation. In the current study, nine small RNA libraries were constructed and sequenced from the antennae of nymphs, adult males and females of Apolygus lucorum. In total, 399 miRNAs were identified including 275 known and 124 novel miRNAs. Known miRNAs were classified into 71 families, amongst which, 23 families were insect-specific. Expression profile analysis showed that miR-7-5p_1 was the most abundant miRNAs in the antennae of A. lucorum. Altogether, 69708 target genes related to biogenesis, membrane and binding activities were predicted for 399 miRNAs. Particularly, 15 miRNAs were found to target 16 olfactory genes. These miRNAs could be involved in regulation of olfactory-associated genes ex-pression. Comparing the antennae of nymphs, adult males and females, 94 miRNAs were found to be differentially expressed. The expression levels of some differentially expressed miRNAs measured by qPCR were consistent with sequencing results. This study provides a global miRNAs transcriptome in the antennae of A. lucorum and valuable information for further investigation on miRNA-mRNA interactions, especially the functions of miRNAs in regulating chemosensation.
ARTICLE | doi:10.20944/preprints202202.0190.v1
Subject: Biology, Entomology Keywords: mites; insects; trophic relation; plant-arthropod interactions; SEKEM; fayoum
Online: 16 February 2022 (02:46:57 CET)
Due to a lack of knowledge about arthropod biodiversity in Egyptian organic agro-ecosystems; the study aimed to introduce information on the diversity, richness, and distribution of insect and mite species in two organic agro-ecosystems, also, to investigate the impact of plant-arthropod interactions. Samples collected from two organic farms, i) Shampoliah farm, Fayoum (GCS 29°21'07.4"N 30°44'17.8"E), and ii) SEKEM farm, Sharkia (GCS 18 30°22'56.1"N 31°39'17.4"E). Results shown 39 species recorded in Shampoliah farm, and 35 species in SEKEM of mite, insect, medicinal, and weed species. When 14 species shared among two sites. Study has measured the H', D and 1/D indices within each location, and the similarity/dissimilarity between locations. The study hypothesized the possible plant-arthropod interactions that explain why diversity differs from an ecosystem to another; due to; plant size, plant morphological characters, soil fertilization, plant nutritional content, and the prey-predator interactions. The added hypothesis; is to show that the importance of natural habitat is supporting natural enemies and distribution of arthropods, which could vary dramatically with the type of pest species, IPM, and landscape type considered.
SHORT NOTE | doi:10.20944/preprints202202.0173.v1
Subject: Biology, Entomology Keywords: Insects; Acari; Araneae; Gastropods; Weeds; Pesticides; Fertilizers; IPM; Arthropod-Plant Interac-tions; Tri-trophic relationship
Online: 14 February 2022 (11:08:33 CET)
The National Research Centre’s experimental research station (NRCERS) locates in Wadi El Natrun, Egypt 30°29'54.22"N 30°19'10.94"E. The NRCERS has various crop yields (vegetables, fruits, ornamental, and field crops) for different experimental treatments. It followed conventional agricultural procedures in vegetation, fertilisation, irrigation, and plant protection. Such policies have not been evaluated for their impacts on arthropod diversity and distribution. Thus, this study conclusion aims to sufficiently map the arthropod species (pest/predators) distribution, measure the biodiversity indices, to the NRCERS agricultural policies to be modified to support arthropod diversity.
ARTICLE | doi:10.20944/preprints202202.0035.v1
Subject: Biology, Entomology Keywords: Aedes albopictus; ovitrap; regularized logistic regression; ecological niche model; environmental factors; surveillance
Online: 2 February 2022 (13:18:11 CET)
Background: In Switzerland, Aedes albopictus is well established in Ticino, south of the Alps, where surveillance and control are implemented. The mosquito has also been observed in Swiss cities north of the Alps. Decision-making tools are urgently needed by the local authorities in order to optimize surveillance and control. Methods: A regularized logistic regression was used to link the long-term dataset of Ae. albopictus occurrence in Ticino with socio-environmental predictors. The probability of establishment of Ae. albopictus was extrapolated to Switzerland and more finely to the cities of Basel and Zurich. Results: The model performed well, with an AUC of 0.86. Ten so-cio-environmental predictors were selected as informative, including the road-based distance in minutes of travel by car from the nearest cell established in the previous year. The risk maps showed high suitability for Ae. albopictus establishment in the Central Plateau, the area of Basel and the lower Rhone Valley in the Canton of Valais. Conclusions: The areas identified as suitable for Ae. albopictus establishment are consistent with the actual current findings of tiger mosquito. Our approach provides a useful tool to prompt authorities’ intervention in the areas where there is higher risk of introduction and establishment of Ae. albopictus.
ARTICLE | doi:10.20944/preprints202201.0023.v1
Subject: Biology, Entomology Keywords: Malaria; Anopheles gambiae; vector control; neonicotinoids; cross-resistance
Online: 4 January 2022 (20:40:51 CET)
Background: New insecticides with novel modes of action such as neonicotinoids have recently been recommended for public health use by WHO. Resistance monitoring of such novel insecticides requires a robust protocol to monitor the development of resistance in natural populations. In this study, we comparatively used three different solvents to assess the susceptibility of malaria vectors to neonicotinoids across Africa.Methods: Mosquitoes were collected from May to July 2021 from three agricultural settings in Cameroon (Njombe-Penja, Nkolondom, and Mangoum), the Democratic Republic of Congo (Ndjili-Brasserie), Ghana (Atatam), and Uganda (Mayuge). Using the CDC bottle test, we compared the effect of three different solvents (ethanol, acetone, acetone+MERO) on the efficacy of neonicotinoids against Anopheles gambiae s.l. In addition, TaqMan assays were used to genotype key pyrethroid-resistant markers in An. gambiae and to evaluate potential cross-resistance between pyrethroids and clothianidin.Results: Lower mortalities were observed for all populations when using absolute ethanol or acetone alone as solvent (11.4- 51.9% mortality for Nkolondom, 31.7- 48.2% for Mangoum, 34.6- 56.1% for Mayuge, 39.4- 45.6% for Atatam, 83.7- 89.3% for Congo and 71.05- 95.9% for Njombe pendja) compared to acetone + MERO for which 100% mortality was observed for all the populations. Synergist assays (PBO, DEM and DEF) revealed a significant increase of mortality suggesting that metabolic resistance mechanisms are contributing to the reduced susceptibility. A negative association was observed between the L1014F-kdr mutation and clothianidin resistance with a greater frequency of homozygote resistant mosquitoes among the dead than among survivors (OR=0.5; P=0.02). However, the I114T-GSTe2 was in contrast significantly associated with a greater ability to survive clothianidin with a higher frequency of homozygote resistant among survivors than other genotypes (OR=2.10; P=0.013). Conclusions: This study revealed a contrasted susceptibility pattern depending on the solvents with ethanol/acetone resulting in lower mortality, thus possibly overestimating resistance, whereas the addition of MERO consistently increased the efficacy of neonicotinoids in terms of percentage mortalities and time to final mortality. The addition of MERO could however prevent the early detection of resistance development. We therefore recommend monitoring susceptibility using both acetone alone and acetone+MERO (8-10µg/ml for clothianidin) to capture the accurate resistance profile of the mosquito populations.
ARTICLE | doi:10.20944/preprints202112.0486.v1
Subject: Biology, Entomology Keywords: Stemona collinsae; Non-Tai-Yak; Topical administration; Didehydrostemofoline; Alkaloids; Cockroach; Insecticide; MALDI IMS
Online: 30 December 2021 (12:39:41 CET)
Contact toxicity against Periplaneta americana has never been tested with S. collinsiae root extract. Hexane, dichloromethane, ethanol and water extracts were tested in final-instar nymphs and adult P. americana by topical application method. The dichloromethane extract showed the high-est potency of contact toxicity against the final-instar nymphs (41-100% corrected mortality at 48 hours), lowest LC50 (1.5±0.2 %w/v at 48 hours), and lowest LT50 (36.1±0.8 hours at 10%w/v) while the water crude extract lacked the contact toxicity (0-0% corrected mortality at 48 hours). Signs of toxicity, such as excited movement, trembling body, motionlessness, and swollen abdomen segment including irregularly extended foregut were found at the both stages of P. americana dropping with solutions of dichloromethane extract. Detection of didehydrostemofoline distri-bution using IMS revealed that didehydrostemofoline distributed in the tissue of the dead fi-nal-instar nymph and adult P. americana contacting with dichloromethane extract, but it was not found in tissue of euthanized P. americana which exposed to the water extract. Didehydrostemo-foline in the extract was a cause of toxicity signs and death of P. americana via a contact route. Thus, dichloromethane extract and didehydrostemofoline could be used as an active ingredient and chemical marker in aerosol and spray formulations for cockroach control.
ARTICLE | doi:10.20944/preprints202112.0146.v1
Subject: Biology, Entomology Keywords: Chironomids; taxonomy; morphometry; principal component analysis
Online: 9 December 2021 (08:39:58 CET)
The larvae of some species of the subgenus Orthocladius s. str. (Diptera, Chironomidae) are here described for the first time with corrections and additions to the descriptions of adult males and pupal exuviae. The identification of larvae is generally not possible without association with their pupal exuviae and/or adult males, so the descriptions here are based only on reared material or on pupae with the associated larval exuviae. Usually, Chironomidae larvae can be separated on the basis of morphometric characters, and the most discriminant characters ones are: 1- the ratio between the width of median tooth of mentum (Dm) and the width of the first lateral tooth (Dl) = mental ratio (DmDl), 2- the ratio between the length of the first antennal segment (A1) and the combined length of segments 2-5 (A(2-5)2-5) = antennal ratio (AR). The shape of mandible, maxilla, and other body parts are almost identical in all the species considered in this study. The larva of Orthocladius (Symposiocladius) lignicola is very characteristic and can be separated by the shape of mentum and the larvae of all the known species of Symposiocladius are characterized by the presence of large Lauterborn organs on antennae and of tufts of setae on abdominal segments. The larvae of Orthocladius (Orthocladius) oblidens and Orthocladius (Orthocladius) rhyacobius can be distinguished from other species basing on their large Dm and to each other by AR. A principal component analysis was carried out using 5 characters: 1- Dm, 2- Dl, 3- length of A1, 4- width of A1 (A1W), 5- combined length of segments 2-5 (A2-5). The most discriminant characters were Dm and A1, confirming that DmDl and AR can be used to separate species at larval stage, but the large superposition of morphometric characters in different species confirms that association with pupal exuviae is in any case needed to identify larvae. In future perspective, the development of reference DNA barcodes from specimens identified by specialists is recommended since possibly the best tool for larvae identification, but association of barcodes with morphotypes is in any case fundamental.
ARTICLE | doi:10.20944/preprints202110.0394.v2
Subject: Biology, Entomology Keywords: heat treatment; termite control; termites; Crytotermes brevis; wood pest; heat technology; non-chemical; pest management; condominium; temperature sensor
Online: 3 December 2021 (10:12:33 CET)
With heat treatments to control drywood termites (Blattodea: Kalotermitidae), the presence of heat sinks causes heat to be distributed unevenly throughout the treatment areas. Drywood termites may move to galleries in heat sink areas to avoid exposure to lethal temperatures. Our studies were conducted in Crytotermes brevis-infested condominiums in Honolulu, Hawaii to reflect real-world condominium scenarios; either a standard heat treatment performed by a heat remediation company or an improved heat treatment was used. For improved treatments, heated air was directed into the toe-kick voids of C. brevis infested cabinets to reduce heat sink effects and increase the heat penetration into these difficult-to-heat areas. Eight thermistor sensors placed inside toe-kick voids, treatment zone, embedded inside cabinets’ sidewalls, and in a wooden cube recorded target temperatures of above 46 °C or 50 °C for 120 minutes. A pretreatment and follow-up inspections were performed at 6 months posttreatment to monitor termite inactivity using visual observations and by recording the numbers of spiked peaks on a microwave technology termite detection device (Termatrac). In improved treatment condominiums, significantly higher numbers of spiked peaks were recorded at pretreatment as compared to 6 months posttreatment. Efficacious heat treatment protocols using the improved methods are proposed.
ARTICLE | doi:10.20944/preprints202111.0538.v1
Subject: Biology, Entomology Keywords: Propoxur; insecticide paint; Aedes aegypti; density reduction; Mexico
Online: 29 November 2021 (12:48:34 CET)
This study investigated the development of Aedes aegypti density in houses of the urban locality of Poblado Miguel Alemán Valdes, in the Sonora state of Mexico, after application of 1% propoxur paint as full wall coverage (IP) and targeted indoor painting (IP 1m) in comparison to IRS with propoxur 70% WP (full wall coverage). The 1% propoxur paint was applied by the homeowners by brushing and rolling at the recommended dose of 1L/8 m², equivalent to 1.5 g a.i./m2, while IRS was conducted by professionals with Propoxur 70% WP at a dose of 1 g a.i./m2. Adult mosquito surveys were conducted in a random sample of houses in each block one week before the interventions and at week 1, month 1 to 4, month 6, month 9 and month 12 post-interventions. All three propoxur based treatments provided similar reductions (43.7%, 44.9% and 41.3% for IP, IP 1m and IRS respectively) in the fraction of houses positive in female Aedes aegypti resting indoor and outdoor as one year average of 8 follow up surveys. Indoor resting density of Aedes females during the one-year evaluation was reduced by 77.5% through IP followed by IP 1m with 64.2% reduction and 30% reduction with IRS. Culex mosquitoes’ interior density was affected as well by the insecticide treatments with similar average reductions for IP 1m (50.0%) and IRS (57.8%) in comparison with control. Aedes breeding was impacted by the insecticide paint in similar extent for both interventions, expressed by a substantial reduction of the House Index (20.1% IP, 31.2% IP 1m) and especially the Container Index (51.8% IP, 61.7% IP 1m) during the one-year surveys in comparison to control. In contrast, IRS treated block experienced an increase in both indexes. However, despite IP and IP 1m impacted in Aedes adult and immature indexes with noticeable reductions, the differences in all cases were not significative among the different insecticide treatments. The low sample size and mosquito population levels may have influenced the statistical outcomes. More than 80% of the interviewed residents were satisfied with the effectiveness of the paint and IRS treatments. The determination of the blood cholinesterase activity of tested individuals after the use of the carbamate paint and IRS in this study did not exceed acceptable inhibition limits. This study suggests that the application of propoxur paint by homeowners as full house coverage or as targeted indoor painting can be a safe and accepted intervention method for density reduction of Aedes aegypti populations in urban environments.
REVIEW | doi:10.20944/preprints202111.0518.v1
Subject: Biology, Entomology Keywords: polystyrene; polyethylene; worms; Hermetia illucens; Tenebrio molitor; Zophobas morio; plastic; bioremediation; food-waste; circular economy
Online: 29 November 2021 (09:47:04 CET)
The negative impact of the modern-day lifestyle on the environment is aggravated during the COVID-19 pandemic through the increased use of single-use plastics from food takeaways to medical supplies. Similarly, the closure of food outlets and disrupted supply chains have also resulted in significant food wastage. As the pandemic rages on, the aggravation of increased waste becomes an increasingly urgent problem that threatens the biodiversity, ecosystems, and human health worldwide through pollution. While there are existing methods to deal with the organic and plastic waste, many of the solutions also cause additional problems. Increasingly proposed as a natural solution to man-made unnatural problems, there are insect solutions for dealing with the artificial and organic waste products towards a circular economy, making the use of natural insect solutions commercially sustainable. This review discusses the findings and how some of these insects, particularly the Hermetia illucens, Tenebrio molitor, and Zophobas morio, can play an increasing important role in food and plastics, with a focus on the latter.
ARTICLE | doi:10.20944/preprints202111.0314.v1
Subject: Biology, Entomology Keywords: Asian hornet; Vespa velutina; Venom; Electrical; Stimulation; Allergy; Stings; Invasive species
Online: 17 November 2021 (23:38:04 CET)
The yellow-legged Asian hornet (Vespa velutina Lepeletier 1836 (Hymenoptera: Vespidae)) is naturally distributed in China, Southeast Asia and India; however it has since detected outside of its native area, confirmed as being established in South Korea, Europe and Japan. Health risks and deaths caused by the invasive Vespa velutina stings have become a public health concern, being the most common cause of anaphylaxis due to hymenopterans in some European regions. This in turn has led to increased demand from medical practitioners and researchers for Vespa velutina venom for diagnostic and therapeutic purposes. In this study, a straightforward, quick and inexpensive method for obtaining Vespa velutina venom by electric stimulation is described. The venom extracts were analyzed by nuclear magnetic resonance spectroscopy (1H-NMR), confirming the composition of the obtained material. The availability of Vespa velutina venom will lead to improved diagnostic and therapeutic methods, mainly by venom immunotherapy (VIT), in patients allergic to this invasive species.
ARTICLE | doi:10.20944/preprints202111.0213.v1
Online: 12 November 2021 (11:20:39 CET)
Pronematus ubiquitus (McGregor) is a small iolinid mite that is capable of establishing on tomato plants. Once established, this mite has been shown to control both tomato russet mite, Aculops lycopersici (Tryon) (Acari: Eriophyidae) and tomato powdery mildew (Oidium neolycopersici L. Kiss). In the present study, we explored the nutritional value of various food sources in the laboratory. First, we assessed the reproduction of two food sources that P. ubiquitus can encounter on a tomato crop: tomato pollen and powdery mildew. In a second laboratory experiment, we evaluated the nutritional value of two types of prey mites: the astigmatid Carpoglyphus lactis L. (Acari: Carpoglyphidae) and the tarsonemid Tarsonemus fusarii (Acari: Tarsonemidae). Powdery mildew and C. lactis did not contribute to the reproduction, whereas tomato pollen and T. fusarii did allow egg-laying. However, Typha angustifolia pollen was a superior food source in both experiments. In a greenhouse trial on individual caged tomato plants, we evaluated the impact of pollen supplementation frequency on establishment of P. ubiquitus. Here, a pollen addition frequency of every other week was required to allow populations of P. ubiquitus to establish.
ARTICLE | doi:10.20944/preprints202111.0206.v1
Subject: Biology, Entomology Keywords: Indoor residual spray (IRS); Vector control; Anopheles; Aedes aegypti; Culex quinquefasciatus; Neonicotinoids; Pyrethroid; Insecticide resistance; SumiShield; K-Othrine.
Online: 10 November 2021 (14:24:24 CET)
Insecticides with novel modes of action are required to complement the pyrethroids currently relied upon for controlling malaria vectors. One example of this is the neonicotinoid clothianidin, which is found in SumiShield™ 50WG used in indoor residual spraying (IRS). In a preliminary experiment, mortality in insecticide susceptible and resistant An. gambiae adults exposed to SumiShield™ 50WG-treated filter papers reached 80% by 3-days post-exposure and 100% by 6-days post-exposure. Next, cement, wood, and mud tiles were treated with SumiShield™ 50WG or K-Othrine® WG250 (deltamethrin IRS formulation) and insecticide resistant and susceptible Anopheles and Aedes were exposed to these surfaces periodically for up to 18-months. Pyrethroid resistant Cx. quinquefasciatus were also exposed at 9 months. Between exposures tiles were stored in heat and relative humidity conditions reflecting those found in the field. On these surfaces, SumiShield™ 50WG was effective at killing both susceptible and resistant An. gambiae for 18 months post-treatment, while mortality amongst the resistant strains when exposed to deltamethrin (K-Othrine® WG250) IRS was not above that of the negative control. Greater efficacy of SumiShield™ 50WG was also demonstrated against insecticide resistant strains of An. funestus compared to deltamethrin, though the potency was lower when compared with An. gambiae. In general, a higher efficacy of SumiShield™ 50WG was observed on cement and mud compared to wood. SumiShield™ 50WG demonstrated poor residual activity against Aedes aegypti and Culex quinquefasciatus. Overall, the results suggest SumiShield™ 50WG is well suited for malaria control.
ARTICLE | doi:10.20944/preprints202110.0054.v2
Subject: Biology, Entomology Keywords: RFID; honey bee behavior; queen tracking; foraging activity; transponder
Online: 10 November 2021 (08:44:00 CET)
The fields of electronics and information technology have witnessed rapid development during the last decades, providing significant technical support to the field of biological sciences. Radio-Frequency Identification (RFID) technology has been used to automate the monitoring of animal location and behaviors in a wide range of vertebrate and invertebrate species, including social insects such as ants and honey bees (Apis mellifera L.) This technology relies on electromagnetic fields to identify and track transponders attached to objects automatically. Implementing new technologies to serve research purposes could be time-consuming and require technical expertise from entomologists and researchers. Herein, we present a detailed description on how to harness RFID technology to serve honey bee research effectively. We describe how to build and operate a 32-antenna RFID system used to monitor various honey bee behaviors such as foraging, robbing, queen and drone mating, which can be used in other social insects as well. Preliminary data related to queen nuptial flights were obtained using this unit and presented in this study. Virgin queens labeled with ~5mg transponders performed multiple (1-4) nuptial/orientation flights a day (9 am to 5 pm) ranging from 8 to 145 seconds each. Contrary to virgin queens, no hive exit was recorded for mated-queens. At full capacity, this unit can monitor up to 32 honey bee colonies concurrently and is self-sustained by a solar panel to work in remote areas. All materials, hardware and software needed to build and operate this unit are detailed in this study, offering researchers and beekeepers a practical solution and a comprehensive source of information enabling the implementation of RFID technology in their research perspective.
ARTICLE | doi:10.20944/preprints202111.0113.v1
Subject: Biology, Entomology Keywords: Body-size; Cerrado; Evolutionary history; Nymphalidae; Phylogeny; Species traits
Online: 5 November 2021 (10:35:29 CET)
Introduction: Body size is correlated with many aspects of an animal species' natural history, such as life span, abundance, dispersal capacity and diet breadth. However, contrasting trends have been reported for the relationship between body size and these ecological traits. Methods: Butterfly species from fruit-feeding guilds were used to investigate whether body size correlates with species abundances, dispersal, permanence, and diet breadth in a Neotropical savanna in Brazil (Cerrado). We used Blomberg’s K and Phylogenetic Generalized Least Squares models (PGLS) to measure phylogenetic signal strength in species traits, and to estimate size-dispersal-diet breadth associations while taking shared ancestry into account. Results: 539 individuals from 27 species were captured, and 190 individuals were recaptured, representing a 35% recapture rate. We found that body size negatively influenced butterfly abundance. In contrast, body size was positively associated with dispersal levels, distance traveled, number of traps visited, individual permanence, and diet breadth. These results indicate that larger butterflies have a greater proportion of dispersing individuals over longer distances, as they permanence were detected over longer periods than their smaller relatives. Moreover, larger butterflies are more generalized, based on the number of host plant families and genera they consume. Smaller butterflies demand fewer resources, which is reflected in their higher survival in small patches, and may explain their lower dispersal ability, and higher diet specialization. Nevertheless, lower dispersal ability, if not compensated by large population sizes, may threaten small-bodied species inhabiting environments with intense deforestation rates, such as the Cerrado. Conclusions: Body size positively influences dispersal and diet breadth in the fruit-feeding butterflies collected in this study.
ARTICLE | doi:10.20944/preprints202110.0123.v1
Subject: Biology, Entomology Keywords: Cnaphalocrocis medinalis; rearing temperatures; development; reproduction; flight performance
Online: 7 October 2021 (15:20:38 CEST)
Understanding how species that follow different life-history strategies respond to stressful temperature can be essential to efficient treatments against agricultural pests. Here we focus on how the development and reproduction of C. medinalis is influenced by exposure to different rearing temperatures in the immature stage. We found that low (18 or 22 °C) or high (30 and 34 °C) rearing temperatures negatively affected the immature development and flight performance compared to the normal temperature 26 °C, with higher larval and pupal mortality, lower pupation and eclosion rates and shorter flight duration and distance. Low rearing temperatures significantly slowed down the immature process, but accelerated adult reproduction. However, high rearing temperatures had the opposite impacts. Interestingly, the flight of adults with un-mature rearing low temperatures (18 and 22 °C) significantly decreased their lifetime fecundity and mating frequency, but increased pre-oviposition period of females compared to the control; On contrast, high rearing temperatures (30 and 34 °C) significantly accelerated onset of oviposition and enhanced synchrony of spawning. These results indicate high rearing temperatures in the immature stage are more likely to trigger the onset of migration, but low rearing temperatures induces adults to have a greater resident propensity with stronger reproductive ability.
ARTICLE | doi:10.20944/preprints202109.0305.v1
Subject: Biology, Entomology Keywords: Krüppel-homologue 1; juvenile hormone; vitellogenin; RNA interference; nanoparticles; reproduction; dominance; aggression; oogenesis
Online: 17 September 2021 (11:18:45 CEST)
Dominance hierarchies are ubiquitous in invertebrates and vertebrates, but little is known on how genes influence dominance rank. Our gaps in knowledge are specifically significant concerning female hierarchies and in insects. To start filling these gaps we studied the social bumble bee Bombus terrestris, in which social hierarchies among females are common and functionally significant. Dominance rank in this bee is influenced by multiple factors, including juvenile hormone (JH) that is a major gonadotropin in this species. We tested the hypothesis that the JH responsive transcription factor Krüppel homologue 1 (Kr-h1) mediates hormonal influence on dominance behavior in the bumble bee. We first developed and validated a perfluorocarbon nanoparticles-based RNA interference protocol for knocking down Kr-h1 expression. We then used this procedure to show that Kr-h1 mediates the influence of JH not only on oogenesis and wax production, but also on aggression and dominance rank. To the best of our knowledge, this is the first study causally linking a gene to dominance rank in social insects, and one of only a few such studies in insects or in female hierarchies. These findings are important for determining whether there are general molecular principles governing dominance rank across gender and taxa.
ARTICLE | doi:10.20944/preprints202109.0252.v1
Subject: Biology, Entomology Keywords: Emerald ash borer; Fraxinus spp.; forest pests; invasive populations; north-west Russia; Saint Pe-tersburg; urban pests
Online: 15 September 2021 (09:46:17 CEST)
Emerald ash borer (EAB), Agrilus planipennis, is an invasive beetle of East Asian origin that in North America and Russia killed millions of ash trees (Fraxinus spp.). In September 2020, EAB was de-tected in Saint Petersburg, becoming resonant event for the metropolitan city. The aim of the present study was to investigate occurrence and ecology of EAB in Saint Petersburg. The presence of two distinct enclave populations of EAB was revealed, each of which has (very likely) been established by separate events of “hitchhiking” transport vehicles. Following the invasion, further spread of EAB in Saint Petersburg was slow and locally restricted, main explanation for which is climatic factor. Due to spread by “hitchhiking”, the possibility of EAB further long-distance ge-ographic spread of EAB in the Baltic Sea region (EU) is high, and not only by ground transport (120–130 km distance from EU borders), but also by ferries transporting cars (traditional means of transportation across the Baltic Sea). In certain cases, development of EAB on F. excelsior was more successful (stem portion colonized, larval densities, number of galleries, exit holes, viable larvae, emerged beetles) than in (adjacent) F. pennsylvanica trees. Observed relatively high EAB-sensitivity of F. excelsior therefore questions the efficacy and benefits of the currently ongoing selection and breeding projects against ash dieback (ADB), caused by Hymenoscyphus fraxineus. Inventory, mapping, and monitoring of surviving F. excelsior trees in areas infested by both ADB and EAB are necessary to acquire genetic resource for work on strategic long-term restoration of F. excelsior, tackling (inevitable) invasion of EAB to the EU.
REVIEW | doi:10.20944/preprints202109.0119.v1
Subject: Biology, Entomology Keywords: Asian tiger mosquito; feeding pattern; minimum infection rate; emerging arboviruses; dengue virus
Online: 7 September 2021 (10:38:13 CEST)
The aim of the work was to update the distribution range of Aedes (Stegomyia) albopictus Skuse in the Americas, review the blood-feeding patterns and compare the minimum infection rate (MIR) of the dengue virus (DENV) between studies of vertical and horizontal transmission. The current dis-tribution of Ae. albopictus encompasses 21 countries in the Americas. Extensive review has been conducted for the blood-feeding patterns of Ae. albopictus. The results suggest that the mosquito is capable of feeding on 16 species of mammals and five species of avian. Humans, dogs, and rats are the most common host. Eight arboviruses with the potential to infect humans and animals have been isolated in Ae. albopictus. In the United States of America (USA), Eastern equine encephalitis virus, Keystone virus, La Crosse Virus, West Nile virus, and Cache Valley virus were isolated in the Asian mosquito. In Brazil, Mexico, Colombia, and Costa Rica, DENV (all serotypes) has been frequently identified in field-caught Ae. albopictus. Overall, the estimated MIR in Ae. albopictus infected with DENV is similar between horizontal (10.95) and vertical transmission (8.28). However, in vertical transmission, there is a difference in the MIR values if the DENV is identified from larvae or adults (males and females emerged from a collection of eggs or larvae). MIR es-timated from larvae is 14.04 and in adults is 4.04. In conclusion, it has to be highlighted that Ae. albopictus is an invasive mosquito with wide phenotypic plasticity to adapt to broad and new areas, it is highly efficient to transmit the DENV horizontally and vertically, it can participate in the inter-endemic transmission of the dengue disease, and it can spread zoonotic arboviruses across forest and urban settings.
ARTICLE | doi:10.20944/preprints202109.0051.v1
Subject: Biology, Entomology Keywords: Helicoverpa zea; Bollworm; CRISPR; Cry1A; Bt Toxin; Genome Editing; Knockout; Functional Genomics; Resistance
Online: 3 September 2021 (08:19:44 CEST)
Members of the insect ATP binding cassette transporter subfamily C2 (ABCC2) in several moth species are known as receptors for the Cry1Ac insecticidal protein from Bacillus thuringiensis (Bt). Mutations that abolish the functional domains of ABCC2 are known to cause resistance to Cry1Ac, although the reported levels of resistance vary widely depending on insect species. In this study, the function of the ABCC2 gene as putative Cry1Ac receptor in Helicoverpa zea, a major pest of over 300 crops, was evaluated using CRISPR/Cas9 to progressively eliminate different functional ABCC2 domains. Results from bioassays with edited insect lines support that muta-tions in ABCC2 was associated with Cry1Ac resistance ratios (RR) ranging from 7.3- to 39.8-fold. No significant differences in susceptibility to Cry1Ac were detected between H. zea with partial or complete ABCC2 knockout, although highest levels of tolerance were observed when knocking out half of ABCC2. Based on >500-1,000-fold RRs reported in similar studies for closely related moth species, the low RRs observed in H. zea knockouts support that ABCC2 is not a major Cry1Ac receptor in this insect.
ARTICLE | doi:10.20944/preprints202012.0826.v2
Subject: Biology, Entomology Keywords: Amegilla; Gossypium barbadens; Meskine; pollination efficiency; yields
Online: 27 August 2021 (14:08:15 CEST)
This study was carried out to evaluate the impact of Amegilla calens bee on fruit and seed yields of G. hirsutum in an experimental field, in September 2018 and 2019. The experiments were carried out on 540 flowers divided in four treatments: 120 flowers accessible to all visitors; 120 flowers bagged to avoid all visits; 200 flowers protected and uncovered when they were opened, to allow A. calens visits; 100 flowers bagged then uncovered and rebagged without the visit of insects or any other organism. Bees daily rhythm of activity, its foraging behaviour on flowers, its pollination efficiency, the fruiting rate, the number of seeds per fruit and the percentage of normal seeds were evaluated. Results indicate that among 11 insect species recorded on flowers, X. olivacea ranked second and harvested nectar. Throughout the pollination efficiency of a single flower visit, X. olivacea provoked a significant increase of the podding rate, the mean number of seeds per pod, the percentage of normal seeds and the mean weight of a seed by 39.48 %, 18.19 %, 49.62 % and 31.53 % respectively. The conservation and installation of X. olivacea nests close to P. vulgaris fields is recommended to improve its pod production and seed quality.
ARTICLE | doi:10.20944/preprints202108.0160.v1
Subject: Biology, Entomology Keywords: Pyrethroid; pyrethroid resistance; insecticide resistance; insecticide resistance management; vector control; malaria; malaria control; mosquito; Anopheles
Online: 6 August 2021 (11:19:25 CEST)
Pyrethroid resistance is widespread in malaria vectors. However, differential mortality in discriminating dose assays to different pyrethroids is often observed in wild populations. When this occurs, it is unclear if this differential mortality should be interpreted as an indication of differential levels of susceptibility within the pyrethroid class, and if so, if countries should consider selecting one specific pyrethroid for programmatic use over another. A review of evidence from molecular studies, resistance testing with laboratory colonies and wild populations, and mosquito behavioural assays was conducted to answer these questions. Evidence suggests that in areas where pyrethroid resistance exists, different results in insecticide susceptibility assays with specific pyrethroids currently in common use (deltamethrin, permethrin, α-cypermethrin and λ-cyhalothrin) are not necessarily indicative of an operationally relevant difference in potential performance. Consequently, it is not advisable to use rotation between these pyrethroids as an insecticide resistance management strategy. Less commonly used pyrethroids (bifenthrin and etofenprox) may have sufficiently different modes of action, though further work would be needed to examine how this may apply to insecticide resistance management.
ARTICLE | doi:10.20944/preprints202107.0696.v1
Subject: Biology, Entomology Keywords: Gustation; sugar aversion; German cockroach; olfactory learning; memory; foraging
Online: 30 July 2021 (10:49:30 CEST)
An association of food sources with odors prominently guides foraging behavior in animals. To understand the interaction of olfactory memory and food preferences, we used glucose-averse (GA) German cockroaches. Multiple populations of cockroaches evolved a gustatory polymorphism where glucose is perceived as a deterrent and enables GA cockroaches to avoid eating glucose-containing toxic baits. Comparative behavioral analysis using an operant conditioning paradigm revealed that learning and memory guide foraging decisions. Cockroaches learned to associate specific food odors with fructose (phagostimulant, reward) within only a 1 hr conditioning session, and with caffeine (deterrent, punishment) after only three 1 hr conditioning sessions. Glucose acted as reward in wild type (WT) cockroaches, but GA cockroaches learned to avoid an innately attractive odor that was associated with glucose. Olfactory memory was retained for at least 3 days after three 1 hr conditioning sessions. Our results reveal that specific tastants can serve as potent reward or punishment in olfactory associative learning, which reinforces gustatory food preferences. Olfactory learning therefore reinforces behavioral resistance of GA cockroaches to sugar-containing toxic baits. Cockroaches may also generalize their olfactory learning to baits that contain the same or similar attractive odors even if they do not contain glucose.
ARTICLE | doi:10.20944/preprints202012.0593.v1
Subject: Biology, Entomology Keywords: epidemiology; X23; fatalities; venomous animals; Spain; stings; hornets; wasps; bees; Vespa velutina
Online: 23 December 2020 (15:24:07 CET)
Epidemiology of fatalities in Spain due to hornet, wasp and bee stings (Cause Code of Death: X23) is described. Over a 20-year period (1999-2018), a total of 78 fatalities were recorded, mostly occurring in males (85.9%), of 65 years and older (52.6%), at “unspecified places” (67.9%) and in the months of July and August (50%). The X23 mortality rates (X23MR) expressed in terms of annual rates and per million inhabitants, varied from 0.02 to 0.19 (mean value ± standard deviation = 0.09 ± 0.05), placing Spain at low levels in comparison with other countries. A more detailed and specific breakdown of the distribution of the yearly deaths at Sub-state level and across communities reveals some striking features. They were more concentrated in the Communities of Galicia (35.8%), Andalucía (21.7%) and Castilla y León (12.8%). X23MR were estimated in Galicia at 1.82, 1.10 and 2.22 in 2014, 2016 and 2018 respectively; and in Asturias at 1.88 and 0.97, in 2014 and 2017 respectively. The role of the invasive species Vespa velutina (VV), is examined. Due to its habits, abundance and broader distribution, the risk that VV represents to human health is unmatched by other Hymenoptera native species.
ARTICLE | doi:10.20944/preprints202012.0454.v1
Subject: Biology, Entomology Keywords: Head lice, haplogroup E, PHUM540560 gene, Acinetobacter haemolyticus, Acinetobacter spp., Guinea.
Online: 18 December 2020 (11:22:55 CET)
Pediculus humanus capitis, the head louse, is an obligate blood-sucking ectoparasite that occurs in six divergent mitochondrial haplogroups (A, D, B, F, C and E), each exhibiting a particular geographic distribution. A few years ago, several studies reported the presence of different pathogenic agents in head lice specimens from different clades collected worldwide. These findings suggest that head louse could be a vector for dangerous diseases and therefore a serious public health problem. Herein, we aimed to study the mitochondrial genetic diversity, the PHUM540560 gene polymorphisms profile of head lice collected in Guinea, as well as to screen for the pathogens present in these lice. In 2018, a total of 155 head lice were collected from 49 individuals at the Medicals Centers of rural (Maférinyah village) and urban (Kindia city) areas, in Guinea. All head lice were subjected to genetic analysis and screened for the presence of several pathogens using molecular tools. The results showed that all head lice belonged to the haplogroups C/E using the duplex qPCR which detects both clades. Standard PCR and sequencing revealed that all specimens belonged to the haplogroup E, including 8 haplotypes, whither 6 new identified for the first time in this study. The study of the PHUM540560 gene polymorphisms in our Guinean head lice revealed that 7/40 (17.5%) of our tested samples exhibit three different polymorphism profiles compared to the clade A-head lice PHUM540560 gene profile, while the remaining specimens 33/40 (82,5%) showed the same PHUM540560 gene polymorphism profile as the previously reported clade A-body lice. Molecular investigations of the targeted pathogens revealed only the presence of Acinetobacter species in 9% of our samples using real time PCR. Sequencing results identified highlighted the presence of several Acinetobacter species, including Acinetobacter baumannii (14.3%), Acinetobacter nosocomialis (14.3%), Acinetobacter variabilis (14.3%), Acinetobacter haemolyticus (7.2%), Acinetobacter towneri (7.2%). Furthermore, a candidate new species of Acinetobacter sp. (7.2%) was detected. Positive specimens were collected from 24,5% individuals in Maférinyah. We also investigated in our study the carbapenem’s-resistant profile of A. baumannii, none of our specimens were positive for the following resistance genes blaOXA-21, blaOXA-24 and blaOXA-58. To the best of our knowledge, our study is the first to report the existence of the Guinean haplogroup E, the PHUM540560 gene polymorphism profile as well as the presence of Acinetobacter species in head lice collected from Guinea.
REVIEW | doi:10.20944/preprints202009.0552.v1
Subject: Biology, Entomology Keywords: Malaria; Amazon; Brazil; Anopheles darlingi; Plasmodium; Control; Challenges; Strategies; Conventional; Novel; Vector; Mosquito
Online: 23 September 2020 (15:26:43 CEST)
In Brazil, malaria transmission is mostly confined to the Amazon, where substantial progress has been achieved towards disease control in the past decade. Vector control has been historically considered a fundamental part of the main malaria control programs implemented in Brazil. However, the conventional vector-control tools have been insufficient to eliminate local vector populations due to the complexity of the Amazonian rainforest environment and ecological features of malaria vector species in the Amazon, especially Anopheles darlingi. Malaria elimination in Brazil and worldwide eradication will require a combination of conventional and new approaches that takes into account the regional specificities of vector populations and malaria transmission dynamics. Here we present an overview on both conventional and novel promising vector-focused tools to curb malaria transmission in the Brazilian Amazon. If well designed and employed, these new vector-based approaches may improve the implementation of malaria-control programs, particularly in remote or difficult-to-access areas and in regions where existing interventions have been unable to eliminate disease transmission. However, much effort still has to be put on research expanding the knowledge of neotropical malaria vectors to set the steppingstones for the development of such innovative tools.
ARTICLE | doi:10.20944/preprints202009.0378.v1
Subject: Biology, Entomology Keywords: morphological diversity; species richness; jewel beetle; geometric morphometrics; elytron; pronotum
Online: 17 September 2020 (05:56:52 CEST)
Correlation between the category richness (CR) and morphological diversity (MD) of some communities at a local scale was found pendent, however, examination of a whole category using a large dataset are lacking. In this study, 1119 jewel species from around the world representing all existing subfamilies and 33.78% of Buprestidae genera were selected as a test group. A geometric morphometric analysis on the contour of homologous traits: pronotum and elytra was conducted to quantify morphological diversity. Correlations between MD and CR among subfamilies were found to be consistently positive with the exceptions of a pronotum genus-level test on the subfamily category. The correlation was also found to be higher at the genus-level than it on the species-level, in both pronotum and elytron measurements. Based on our analyses the hypothesis of positive correlations was expected in the genus-level test of jewel beetles but rejected in species-level test. The inconsistent correlation between morphological diversity and species richness revealed convergent morphological variation of pronotum under the similar functional diversity in Buprestidae. In addition, our test revealed variable correlation between MD and CR based on different groups and characters, which might be caused by morphological changes under coevolution with different ecological factors.
COMMUNICATION | doi:10.20944/preprints202008.0231.v1
Online: 10 August 2020 (03:13:56 CEST)
Aedes aegypti is the primary mosquito vector of several human arboviruses including dengue virus (DENV). Vector control is the principal intervention to decrease the transmission of these viruses. The characterization of molecules involved in the mosquito physiological responses to blood-feeding may help to identify novel targets useful in the design of effective control strategies. In this study, we evaluated the in vivo effect of feeding adult female mosquitoes with human blood containing either heat-inactivated (IB), normal serum (NB), and RNA-seq based transcript expression was compared against sugar-fed (SF) mosquitoes. In the in vitro experiments, we treated Aag2 cells with a recombinant version of the complement proteins (hC3 or hC5a) and compared transcript expression to untreated control cells after 24h. The transcript expression analysis revealed that human complement proteins modulate approximately 2,300 transcripts involved in multiple biological functions, including the immune system. We also found 161 up-regulated and 168 down-regulated transcripts differentially expressed when hC3 and hC5a were compared against the control untreated cells. We conclude that active human complement induces significant changes in the transcriptome of Ae. aegypti mosquitoes, which can influence the infective capacity of pathogens ingested during blood meals.
BRIEF REPORT | doi:10.20944/preprints202007.0503.v1
Subject: Biology, Entomology Keywords: beekeeping; honey bees; honey production; bee forage plants; honey producing capacity
Online: 22 July 2020 (06:26:48 CEST)
Pakistan is an important country located in South Asia and ranks the world's sixth most populous country. It has diverse landscapes with their own specific vegetation. The country specific vegetative diversity has a great ecological and economic impact on the conservation of local fauna. It has huge potential for sustainable beekeeping industry if properly exploited. Beekeeping in Pakistan is mainly focused in Khyber Pakhtunkhwa and central and north regions of Punjab provinces but nowadays it is growing rapidly across the country. Honey produced in Pakistan enjoys good repute in the Middle East due to its unique taste and quality. Pakistan exports around 4000 tons of the honey with the worth of about $ 23.00 million to Arab countries every year.
ARTICLE | doi:10.20944/preprints202007.0377.v1
Subject: Biology, Entomology Keywords: mosquito; Anopheles; microbiota; malaria; Plasmodium; metabolism; immunity; TCA cycle; nitrogen excretion; amino acids
Online: 17 July 2020 (11:00:53 CEST)
The mosquito microbiota reduces the vector competence of Anopheles to Plasmodium and affects host fitness, it is therefore considered as a potential target to reduce malaria transmission. While immune induction, secretion of antimicrobials and metabolic competition are three typical mechanisms of microbiota-mediated protection against invasive pathogens in mammals, the involvement of metabolic competition or mutualism in mosquito-microbiota and microbiota-Plasmodium interactions has not been investigated. Here, we describe a metabolome analysis of the midgut of An. coluzzii provided with a sugar-meal or a blood-meal, under conventional or antibiotic-treated conditions. We observed that the antibiotic treatment affects the tricarboxylic acid cycle and nitrogen metabolism, notably resulting in decreased abundance of free amino acids. Linking our results with published data, we identified candidate pathways which may participate in microbiota/Plasmodium interactions via metabolic interactions or immune modulation.
REVIEW | doi:10.20944/preprints202007.0357.v1
Online: 16 July 2020 (13:21:38 CEST)
The key premise of translational studies is that knowledge gained in one animal species can be transposed to other animals. So far translational bridges have mainly relied on genetic and physiological similarities, in experimental setups where behaviours and environment are often oversimplified. These simplifications were recently criticised for decreasing the intrinsic value of the published results. The inclusion of wild behaviour and rich environments in neuroscience experimental designs is difficult to achieve because no animal model has it all. As an example, the genetic toolkit of moths species is virtually non-existent when compared to C. elegans, rats, mice, or zebrafish, however the balance is reversed for wild behaviours. The ethological knowledge gathered about the moth was instrumental for designing natural-like auditory stimuli, that were used in association with electrophysiology in order to understand how moths use these variable sounds produced by their predators in order to trump death. Conversely, we are still stuck with understanding how male moths make sense of their complex and diffuse olfactory landscape in order to locate conspecific females up to several hundred meters away, and precisely identify a conspecific in a sympatric swarm in order to reproduce. This systemic review articulates the ethological knowledge pertaining to this unresolved problem and leverages the paradigm to gain insight into how male moths process sparse and uncertain environmental sensory information.
ARTICLE | doi:10.20944/preprints202007.0004.v1
Online: 2 July 2020 (12:52:53 CEST)
Malaria remains a life-threatening disease in many tropical countries. Honduras has successfully reduced malaria transmission as different control methods have been applied focusing mainly on indoor mosquitoes. The selective pressure exerted by the use of insecticides inside the households could modify the feeding behavior of the mosquitoes forcing them to search for available animal hosts outside the houses. These animal hosts in the peridomicile could consequently become an important factor in maintaining vector populations in endemic areas. Herein, we investigated the blood meal sources and Plasmodium spp. infection on anophelines collected outdoors in endemic areas of Honduras. Individual PCR reactions with species-specific primers were used to detect five feeding sources on 181 visibly engorged mosquitoes. In addition, a subset of these mosquitoes where chosen for pathogen analysis by a nested PCR approach. Most mosquitoes fed on multiple hosts (2 to 4), and 24.9% of mosquitoes were fed on a single host, animal or human. Chicken and bovine were the most frequent blood meal sources (29.5% and 27.5% respectively). The average human blood index (HBI) was 22.1%. None of the mosquitoes was found to be infected with Plasmodium spp. Our results show the opportunistic and zoophilic behavior of Anopheles mosquitoes in Honduras.
REVIEW | doi:10.20944/preprints202002.0374.v2
Online: 2 April 2020 (12:16:16 CEST)
The parasitic mite, Varroa destructor, has shaken the beekeeping and pollination industries since its spread from its native host, the Asian honey bee (Apis cerana), to the naïve European honey bee (A. mellifera) used commercially for pollination and honey production around the globe. Varroa is the greatest threat to honey bee health. Worrying observations include increasing acaricide resistance in the varroa population and sinking economic treatment thresholds, suggesting that the mites or their vectored viruses are becoming more virulent. Highly infested weak colonies facilitate mite dispersal and disease transmission to stronger and healthier colonies. Here, we review recent developments in the biology, pathology and management of varroa, and integrate older knowledge that is less well known.
ARTICLE | doi:10.20944/preprints202003.0127.v1
Subject: Biology, Entomology Keywords: plant-insect interaction; host shift; parallel evolution; detoxification; experimental evolution; population genomics; genome-wide association mapping; gene expression; Callosobruchus maculatus
Online: 8 March 2020 (01:52:10 CET)
Genes that affect adaptive traits have been identified, but our knowledge of the genetic basis of adaptation in a more general sense (across multiple traits) remains limited. We combined population-genomic analyses of evolve and resequence experiments, genome-wide association mapping of performance traits, and analyses of gene expression to fill this knowledge gap, and shed light on the genomics of adaptation to a marginal host (lentil) by the seed beetle Callosobruchus maculatus. Using population-genomic approaches, we detected modest parallelism in allele frequency change across replicate lines during adaptation to lentil. Mapping populations derived from each lentil-adapted line revealed a polygenic basis for two host-specific performance traits (weight and development time), which had low to modest heritabilities. We found less evidence of parallelism in genotype-phenotype associations across these lines than in allele frequency changes during the experiments. Differential gene expression caused by differences in recent evolutionary history exceeded that caused by immediate rearing host. Together, the three genomic data sets suggest that genes affecting traits other than weight and development time are likely to be the main causes of parallel evolution, and that detoxification genes (especially cytochrome P450s and beta-glucosidase) could be especially important for colonization of lentil by C. maculatus.
ARTICLE | doi:10.20944/preprints202002.0255.v1
Subject: Biology, Entomology Keywords: BMSB; Halyomorpha halys; inherited sterility; irradiation; SIT
Online: 18 February 2020 (03:15:20 CET)
The irradiation biology of the brown marmorated stink bug (BMSB, Halyomorpha halys Stål) treated at the nymphal stage was investigated to determine its application for sterile insect technique (SIT). Fifth instar males of BMSB were exposed to gamma-radiation 60Co at different doses of 12, 16, 20, 24 and 64 Gy. Irradiated males were mated with non-irradiated virgin females to assess the longevity of both sexes, female fecundity and fertility of their offspring until the egg stage of the F2 generation. The mortality of each of the developmental stages of the F1 and eggs of the F2 generation was observed to determine whether negative effects from exposure to radiation was inherited. The data indicated that irradiation significantly reduced the lifespan of male insects at doses above 20Gy. Irradiated males did not affect the longevity and fecundity of their female partners, nor either sex of their resulting progeny, but it did reduce the hatch rate of the eggs at all doses tested. The sterility rates of F1 eggs were 55.6%, 73.3%, 74.1% and 74.1% at doses of 12Gy, 16Gy, 20Gy and 24Gy respectively. Eggs were completely sterile (100%) at a dose of 64Gy with no egg hatch recorded. A low hatch rate of F2 eggs illustrated that negative effects from radiation was inherited by the subsequent generation. The results support the potential for the use of SIT for BMSB management by irradiating the fifth instar male nymphs at 16-64Gy.
REVIEW | doi:10.20944/preprints202001.0276.v1
Subject: Biology, Entomology Keywords: genetic improvement; genetic variation; heritability; systematic review; biocontrol agent; life history traits
Online: 24 January 2020 (10:39:55 CET)
The concept of genetic improvement in relation to biological control involves the exploitation of natural genetic variation for the benefit of existing biological control agents (BCAs). Despite recent calls for this process to be adopted in biological control research, there is no clear overview of the current state of research into genetic variation within a biological control context, including quantifiable estimates such as narrow-sense heritability (h2). In this systematic review, we aim to determine the current state of research on the genetic variation of biological control traits in natural enemies. After the searching process, screening for papers that can deliver on our research question reduced the initial 2,927 search hits to only a mere 69 papers for data extraction. Of these, the majority (73.6%) did not report quantitative values for genetic variation. Extracting the traits measured in these papers, we categorized them according to two approaches; the first related to fitness components, and the second related to biological control importance. This systematic review highlights the need for more rigorous reporting of the quantitative values of genetic variation to enable the successful genetic improvement of biological control agents.
SHORT NOTE | doi:10.20944/preprints202001.0196.v1
Subject: Biology, Entomology Keywords: reproducibility; open access; data curation; data mangement; pre-print servers
Online: 18 January 2020 (09:05:49 CET)
The ability to replicate scientific experiments is a cornerstone of the scientific method. Sharing ideas, workflows, data, and protocols facilitates testing the generalizability of results, increases the speed that science progresses, and enhances quality control of published work. Fields of science such as medicine, the social sciences, and the physical sciences have embraced practices designed to increase replicability. Granting agencies, for example, may require data management plans and journals may require data and code availability statements along with the deposition of data and code in publicly available repositories. While many tools commonly used in replicable workflows such as distributed version control systems (e.g. “git”) or scripted programming languages for data cleaning and analysis may have a steep learning curve, their adoption can increase individual efficiency and facilitate collaborations both within entomology and across disciplines. The open science movement is developing within the discipline of entomology, but practitioners of these concepts or those desiring to work more collaboratively across disciplines may be unsure where or how to embrace these initiatives. This article is meant to introduce some of the tools entomologists can incorporate into their workflows to increase the replicability and openness of their work. We describe these tools and others, recommend additional resources for learning more about these tools, and discuss the benefits to both individuals and the scientific community and potential drawbacks associated with implementing a replicable workflow.
ARTICLE | doi:10.20944/preprints201911.0376.v1
Subject: Biology, Entomology Keywords: steppe; habitat fragmentation; carabid beetles; community; richness; abundance
Online: 29 November 2019 (10:40:21 CET)
It is well known that human activities and climate change have increased steppe habitat loss and fragmentation in Northwest China. Carabid beetles are often used as bioindicators of environmental change because they are extremely sensitive to disturbance. We chose 42 landscapes (18 fragmented and 24 continuous) in both desert and typical steppes of Northwest China to examine the influence of habitat loss and fragmentation on carabid beetle communities. The results showed the largest correlation coefficient between carabid communities and landscape compositions within a 7-km spatial scale in both desert and typical steppes. Further, the response of carabid communities to habitat fragmentation was species-specific in both desert and typical steppes. Habitat fragmentation in the desert steppe had positive effects on the richness and abundance of carabid communities, while in the typical steppe, the effects were negative. Additionally, habitat fragmentation significantly decreased the abundance of two common carabid species in the desert steppe. Therefore, the effects of habitat fragmentation on carabid biodiversity differ with species characteristics and habitat traits, where plant communities, soil structure, and microclimate vary in the different steppe types. The results of this study provide experimental evidence and technical support for biodiversity conservation management in the steppes of Northwest China.
REVIEW | doi:10.20944/preprints201911.0300.v1
Subject: Biology, Entomology Keywords: artificial selection; biological control; genetics; genome assembly; genomics; insect breeding; microbiome; modelling
Online: 24 November 2019 (17:10:31 CET)
Biological control is widely successful for controlling pests, but effective biocontrol agents are now more difficult to obtain due to more restrictive international trade laws. Coupled with increasing demand, the efficacy of existing and new biocontrol agents needs to be improved with genetic and genomic approaches. Although they have been underutilised in the past, applying genetic and genomic techniques is becoming more feasible from both technological and economic perspectives. We review current methods and provide a framework for using them, incorporating evolutionary and ecological principles. First, it is necessary to identify which biocontrol trait to select and in what direction. Next, the genes or markers linked to these traits need be determined to better target their selection, followed by how to implement this information into a breeding program. Choosing a trait can be assisted by modelling to account for the proper agro-ecological context, and by knowing which traits have sufficiently high heritability values. We provide guidelines for designing genomic strategies in biocontrol programs, which depends on the organism, budget, and desired objective. Genomic approaches start with genome sequencing and assembly. We provide a guide for deciding the most successful sequencing strategy for biocontrol agents. Gene discovery involves quantitative trait loci (QTL) analyses, transcriptomic and proteomic studies, and gene editing. Improving biocontrol practices include marker-assisted selection, genomic selection and microbiome manipulation of biocontrol agents, and monitoring for genetic variation during rearing and post-release. We conclude by identifying the most promising applications of genetic and genomic methods to improve biological control efficacy.
REVIEW | doi:10.20944/preprints201911.0093.v1
Subject: Biology, Entomology Keywords: microarthropods; decomposition; nutrient mineralization; multi-channel feeding; predation; alternate prey; detrital shunting
Online: 8 November 2019 (10:39:16 CET)
Two desirable functions of healthy soil are nutrient cycling and pest suppression. We review recent literature on the contributions of soil microarthropods to soil health through their intersecting roles in decomposition and nutrient cycling and direct and indirect suppression of plant pests. Microarthropods can impact soil and plant health directly by feeding on pest organisms or serving as alternate prey for larger predatory arthropods, and indirectly, by mediating the ability of crop plants to resist or tolerate insect pests and diseases through interactions with the decomposition food web in support of plant nutrition. Soil fauna, including microarthropods, are key regulators of decomposition at local scales but their role at larger scales is unresolved. Future research priorities include the incorporation of multi-channel omnivory into food web modeling and understanding the vulnerability of our soil carbon to increased global temperatures.
ARTICLE | doi:10.20944/preprints201902.0215.v4
Subject: Biology, Entomology Keywords: coevolution; herbivory; host-plant specialization; phylogeny; speciation
Online: 17 October 2019 (10:12:05 CEST)
During the last two decades, ecological speciation has been a major research theme in evolutionary biology. Ecological speciation occurs when reproductive isolation between populations evolves as a result of niche differentiation. Phytophagous insects represent model systems for the study of this evolutionary process. The host-plants on which these insects feed and often spend parts of their life cycle constitute ideal agents of divergent selection for these organisms. Adaptation to feeding on different host-plant species can potentially lead to ecological specialization of populations and subsequent speciation. This process is thought to have given birth to the astonishing diversity of phytophagous insects and is often put forward in macroevolutionary scenarios of insect diversification. Consequently, numerous phylogenetic studies on phytophagous insects have aimed at testing whether speciation driven by host-plant adaptation is the main pathway for the diversification of the groups under investigation. The increasing availability of comprehensive and well-resolved phylogenies and the recent developments in phylogenetic comparative methods are offering an unprecedented opportunity to test hypotheses on insect diversification at a macroevolutionary scale, in a robust phylogenetic framework. Our purpose here is to review the contribution of phylogenetic analyses to investigate the importance of plant-mediated speciation in the diversification of phytophagous insects and to present suggestions for future developments in this field.
ARTICLE | doi:10.20944/preprints201909.0012.v2
Subject: Biology, Entomology Keywords: Ace-1 G119S mutation; insecticide resistance; Anopheles gambiae; Cameroon; malaria
Online: 8 October 2019 (11:49:05 CEST)
Growing resistance is reported to carbamate insecticides in malaria vectors in Cameroon. However, the contribution of acetylcholinesterase (Ace-1) to this resistance remains uncharacterised. Here, we established that the G119S mutation is driving resistance to carbamates in Anopheles gambiae populations from Cameroon. Insecticide bioassay on field collected mosquitoes from Bankeng, a locality in southern Cameroon, showed high resistance to the carbamates bendiocarb (64.8 ± 3.5 % mortality) and propoxur (55.71 ± 2.9 %) but a full susceptibility to the organophosphate fenithrothion. The TaqMan genotyping of the G119S mutation in field-collected adults revealed the presence of this resistance allele (39%). A significant correlation was observed between the Ace-1R and carbamate resistance at allelic [(bendiocarb; OR = 75.9; P<0.0001) and (propoxur; OR= 1514; P<0.0001)] and genotypic [RR vs SS (bendiocarb; OR = 120.8; P<0.0001) and (propoxur; OR= 3277; P<0.0001) levels. Furthermore, the presence of the mutation was confirmed by sequencing an Ace-1 portion flanking codon 119. The cloning of this fragment revealed a likely duplication of Ace-1 in Cameroon as mosquitoes exhibited at least three distinct haplotypes. Phylogenetic analyses showed that the predominant Ace-1R allele is identical to that from West Africa suggesting a recent introduction of this allele in Central Africa from the West. The spread of this Ace-1R represents a serious challenge to future implementation of IRS-based interventions using carbamates or organophosphates in Cameroon
ARTICLE | doi:10.20944/preprints201910.0026.v1
Subject: Biology, Entomology Keywords: ticks; Ixodes scapularis; serine protease; blood digestion; trypsin
Online: 2 October 2019 (08:56:27 CEST)
Ixodes scapularis is the major vector of Lyme disease in the eastern United States. This species undergoes a life cycle consisting of eggs and three active stages: larva, nymph, and adult. Each active life stage takes a blood meal either for developing and molting to the next stage (larvae and nymphs) or for oviposition (adult females). This protein rich blood meal is the only food taken by Ixodes ticks. Most studies on blood digestion in ticks have shown that the initial stages of blood digestion are carried out by cathepsin proteases within endosomes of acidic digestive cells. However, in other hematophagous arthropods, the serine protease trypsin plays an important role in early protein degradation. In this study, we determined transcript expression of I. scapularis cathepsins and serine proteases, some with previously characterized roles in blood digestion. Gut pH was also determined and a trypsin-benzoyl-D, L-arginine 4-nitoanilide assay was used to measure active trypsin levels during blood digestion. Our data suggest that trypsin levels increase significantly after blood feeding and peaked in larvae, nymphs, and adults at 3, 1, and 1 days post host detachment, respectively. In addition, alkaline gut pH (8.0) conditions after I. scapularis blood feeding were similar to those required for trypsin activity in other arthropods suggesting these enzymes have an important and previously overlooked role in I. scapularis blood digestion.
Subject: Biology, Entomology Keywords: host plant resistance; pest management; Planococcus ficus; vineyard
Online: 11 September 2019 (02:41:28 CEST)
Mealybugs cause economic loss to vineyards through physical damage, fouling fruit and leaves with honeydew, and the transmission of viruses. Planococcus ficus is one of several mealybug species in vineyards, and one that causes economic damage over a relatively large global range. To develop novel management tools, host resistance to P. ficus, which has not previously been identified for any grape cultivars, was studied. Ten grape lines (species, cultivars, and rootstocks) were evaluated for P. ficus resistance across two separate potted plant assays. Significant differences were detected among cultivars and rootstocks in the recorded number of P. ficus juveniles, adults and egg sacs. Cabernet Sauvignon and Chardonnay were two of the most susceptible grape cultivars for mealybug population growth, whereas rootstocks IAC 572, 10-17A and RS-3 all demonstrated some level of resistance. Southern fire ant (Solenopsis xyloni) was positively associated with mealybug populations, but did not have a negative effect on the observed presence of other arthropod species including potential predators.
COMMUNICATION | doi:10.20944/preprints201908.0034.v1
Subject: Biology, Entomology Keywords: freshwater insects; gut microbiome; nitrogen provisioning; nitrate reduction
Online: 5 August 2019 (00:48:14 CEST)
Biological nitrogen (N) provisioning is a seminal function of the gut microbes in several terrestrial insects, given the unbalanced carbon (C) and N ratios of their diets. Although freshwater insects face comparable dietary N limitations like terrestrial insects, little is known about this function by their gut microbiomes. In this study, we investigated microbial nitrate reduction to ammonium pathways as possible routes of biological N provisioning in two freshwater insects; filter-feeding Hydropsychidae and grazers/collectors Baetidae. After incubation in filtered (microbe-free) artificial stream water (ASW) containing dissolved 15N-labeled nitrate (treatment) or standard nitrate (control), bulk δ15N values of treatment samples (Baetidae = 100.62 ± 10.23, mean ± S.E.; Hydropsychidae = 76.82 ± 7.20) were significantly higher than controls (Baetidae = 10.14 ± 0.12 ; Hydropsychidae = 9.03 ± 0.20) in both functional feeding groups (F (3, 13) = 296, P < 0.0001). The treatment δ15N values are cautiously interpreted as reflecting uptake and incorporation of microbe-derived 15N-metabolites (15NH4 or 15N-amino acids) into host tissues following nitrate reduction to ammonium pathways in the gut lumen. Microbial nitrate reduction to ammonium activities was assessed via the quantification of dissimilatory (nrfA) and assimilatory (nasA) nitrate reduction to ammonium gene transcripts. There were no significant differences between control and treatment groups within each insect groups. Overall, this study provides a demonstration of the feasibility of applying 15N-stable isotope analysis for investigating, potential symbiotic functions of freshwater insect gut microbiomes, despite the preliminary nature of the results.
ARTICLE | doi:10.20944/preprints201905.0384.v2
Subject: Biology, Entomology Keywords: Arachnida; insect; phylogenomics methods; target enrichment; ultraconserved elements
Online: 4 August 2019 (16:54:42 CEST)
Targeted enrichment of ultraconserved elements (UCE) has emerged as a promising tool for inferring evolutionary history in many taxa, with utility ranging from phylogenetic and phylogeographic questions at deep time scales to population level studies at shallow time scales. However, the methodology can be daunting for beginners. Our goal is to introduce UCE phylogenomics to a wider audience by summarizing recent advances in arthropod research, and to familiarize readers with background theory and steps involved. We define terminology used in association with the UCE approach, evaluate current laboratory and bioinformatic methods and limitations, and, finally, provide a roadmap of steps in the UCE pipeline to assist phylogeneticists in making informed decisions as they employ this powerful tool. By facilitating increased adoption of UCE in phylogenomics studies that deepen our comprehension of the function of these markers across widely divergent taxa, we aim to ultimately improve understanding of the arthropod tree of life.
ARTICLE | doi:10.20944/preprints201908.0031.v1
Subject: Biology, Entomology Keywords: Buruli ulcer; symbiosis; Limnogonus; pond skater; riffle bug; Rhagovelia; Metrocoris; Trepobates
Online: 2 August 2019 (11:58:07 CEST)
Buruli ulcer (BU), caused by Mycobacterium ulcerans, is a neglected tropical disease associated with freshwater habitats. A variety of limnic organisms harbor this pathogen, including aquatic bugs (Hemiptera: Heteroptera), which have been hypothesized to be epidemiologically important reservoirs. Aquatic Hemiptera exhibit high levels of diversity in the tropics, but species identification remains challenging. In this study, we collected aquatic bugs from emerging foci of BU in the Southwest Region of Cameroon, which were identified using morphological and molecular methods. The bugs were screened for mycobacterial DNA and a selection of 20 mycobacteria-positive specimens from the families Gerridae and Veliidae were subjected to next-generation sequencing. Only one individual revealed putative M. ulcerans DNA, but all specimens contained sequences from the widespread alpha-proteobacterial symbiont, Wolbachia. Phylogenetic analysis placed the Wolbachia sequences into supergroups A, B and F. Circularized mitogenomes were obtained for seven gerrids and two veliids, the first from these families for the African continent. This study suggests that aquatic Hemiptera may have a minor role (if any) in the spread of BU in Southwest Cameroon. Our metagenomic analysis provides new insights into the incursion of Wolbachia into aquatic environments and generates valuable resources to aid molecular taxonomic studies of aquatic Hemiptera.
ARTICLE | doi:10.20944/preprints201906.0071.v2
Subject: Biology, Entomology Keywords: genitalia; terminalia; anatomy; Drosophila melanogaster; nomenclature
Online: 27 July 2019 (02:10:53 CEST)
Animal terminalia represent some of the most diverse and rapidly evolving structures in the animal kingdom, and for this reason have been a mainstay in the taxonomic description of species. The terminalia of Drosophila melanogaster, with its wide range of experimental tools, have recently become the focus of increased interest in the fields of development, evolution, and behavior. However, studies from different disciplines have often used discrepant terminologies for the same anatomical structures. Consequently, the terminology of genital parts has become a barrier to integrating results from different fields, rendering it difficult to determine what parts are being referenced. We formed a consortium of researchers studying the genitalia of D. melanogaster to help establish a set of naming conventions. Here, we present a detailed visual anatomy of male genital parts, including a list of synonymous terms, and suggest practices to avoid confusion when referring to anatomical parts in future studies. The goal of this effort is to facilitate interdisciplinary communication and help newcomers orient themselves within the exciting field of Drosophila genitalia.
Subject: Biology, Entomology Keywords: mosquito; Aedes aegypti; Diptera; Culicidae; insect growth regulator; pyriproxyfen
Online: 22 May 2019 (09:45:59 CEST)
Abstract: Aedes aegypti were exposed to water treated with mosquitocidal chips containing the insecticide pyriproxyfen in a polymer formulation. Chips were tested under different conditions; different water volumes, in containers made of different material, and in water with different levels of organic matter. Treated chips caused 100% mortality of Ae. aegypti during their pupal stage independent of conditions chips were exposed to in water. When tested for longevity, the chips containing 840 µg of pyriproxyfen killed 100% of Ae. aegypti for 4 sequential months of the chips being reused in water. Chips containing 8.4 µg of pyriproxyfen ceased to work after the first week of treatment. When mosquitocidal chips were used in > 25% of the oviposition containers within their cages, there was a significant control of the mosquito populations. Mosquitocidal chips worked in different environments, lasted for extended periods of time, caused significant mosquito population decreases, and were effective in controlling Ae. Aegypti.
ARTICLE | doi:10.20944/preprints201905.0034.v1
Subject: Biology, Entomology Keywords: long-term; sex ratio; action threshold; pest management; insecticide use
Online: 6 May 2019 (08:19:10 CEST)
A long-term investigation of D. suzukii dynamics in wild blueberry fields from 2012 - 2018 demonstrates relative abundance is still increasing seven years after initial invasion. Relative abundance is determined by physiological date of first detection and air temperatures the previous winter. Date of first detection of flies does not determine date of fruit infestation. The level of fruit infestation is determined by year, fly pressure, and insecticide application frequency. Frequency of insecticide application is determined by production system. Non-crop wild fruit and predation influences fly pressure; increased wild fruit abundance results in increased fly pressure. Increased predation rate reduces fly pressure, but only at high abundance of flies, or when high levels of wild fruit are present along field edges. Male sex ratio might be declining over the seven years. Action thresholds were developed from samples of 92 fields from 2012 - 2017 that related cumulative adult male trap capture to the following week likelihood of fruit infestation. A two-parameter gamma density function describing this probability was used to develop a risk-based gradient action threshold system. The action thresholds were validated from 2016-2018 in 35 fields and were shown to work well in two of three years (2016 and 2017).
ARTICLE | doi:10.20944/preprints201905.0014.v1
Subject: Biology, Entomology Keywords: phototactic response; Mythimna separata; LED; wavelength; attraction rate; luminance intensity; sensitivity
Online: 5 May 2019 (11:18:56 CEST)
Recently, light traps using light-emitting diode (LED) lights have been applied to monitor or control insect pests. The oriental armyworm, Mythimna separata Walker, is an important insect pest that has caused damage to several cereal crops, including corn, wheat and rice. The present study aims to seek out a sensitive wavelength causing high phototactic response in M. separata. The study evaluated the phototactic responses of M. separata moths to several LED lights of different wavelengths and luminance intensities under laboratory condition. Results showed that green (520 nm) LED light resulted in significant phototactic response of M. separata moths compared to LED lights of other wavelengths. Additionally, the highest attraction rate of the moths to green LED light appeared in luminance intensity group of 200 lux compared to the other intensities groups. Experiments under optimum conditions based on the above experiments revealed that the green LED light exhibited the strongest attraction rate (64.44%) among all experimental groups. An experiment performed in a net cage also showed that green LED light resulted in the highest phototactic response of M. separata moths, 1.7 times more than a commercial black light used as control. These findings clearly demonstrate that M. separata moths have a high sensitivity to the green LED light. Therefore, a light trap equipped with green LED light could be useful for monitoring and controlling M. separata moths.
ARTICLE | doi:10.20944/preprints201904.0166.v1
Subject: Biology, Entomology Keywords: antimicrobial peptides; cellular defense; insect pathology; phenoloxidae; phospholipase A2; protease
Online: 15 April 2019 (11:45:11 CEST)
Xenorhabdus nematophila and Photorhabdus luminescens are entomopathogenic symbionts that produce several toxic proteins that can interfere with the immune system of insects. Here, we showed that outer membrane proteins (OMPs) could be involved as virulence factors during bacterial symbiont pathogenesis. Purified OMPs from bacterial culture were injected fifth instar larvae of Spodoptera exigua Hübner. Larvae were surveyed for fluctuations in total haemocyte counts (THC), granulocyte percentage (cellular defence), protease, phospholipase A2 (PLA2), and phenoloxidase (PO) activities (humoral defence) at specific time intervals. Changes in the expression of the three antimicrobial peptides (AMPs), cecropin, attacin, and spodoptericin, were also measured. Larvae treated with both types of OMPs had more haemocytes than did the negative controls. OMPs of X. nematophila caused more haemocyte destruction than did the OMPs of P. luminescens. The OMPs of both bacterial species initially activated insect defensive enzymes post-injection, their activating fluctuated in different ways. Attacin, cecropin and spodoptericin were up-regulated by OMP injections more than in normal larvae. The expression of these three AMPs was maximal at four hpi with P. luminescens OMPs treatment. Expression of the three AMPs in X. nematophila treatment was irregular and lower than in the P. luminescens OMPs treatment. These findings provide insights into the role of OMPs of entomopathogenic nematode bacterial symbionts in countering the physiological defenses of insects.
ARTICLE | doi:10.20944/preprints201903.0152.v1
Online: 14 March 2019 (08:59:13 CET)
(E)-β-ocimene was the only found volatile chemical emitted by whole, live worker larvae of Apis mellifera L. by sampling in the vapor phase. While in addition to (E)-β-ocimene, there is evidence for the existence of other volatiles; but the changes of their composition and contents remain unknown during larval development, as are their differences from larvae to larval food. This is the main purpose of the study. We investigated volatile components of worker larvae and larval food using solid phase dynamic extraction (SPDE) coupled with gas chromatography-mass spectrometry (GC-MS). Nine compounds were identified with certainty and six tentatively, consisting of terpenoids, aldehydes, hydrocarbons, ester and ketone. The contents of volatiles of the second-instar worker larvae differ greatly from larvae of other stages mainly attributable to terpenoids, which made the second-instar worker larvae had significantly higher amounts of overall volatiles. Larval food contained significantly higher amounts of aldehydes and hydrocarbons than the corresponding larvae from the fourth to fifth-instar. We discovered volatiles in worker larvae and their food which were never reported before; we also mastered the change of these volatiles’ contents during larval development.
ARTICLE | doi:10.20944/preprints201903.0099.v1
Subject: Biology, Entomology Keywords: genetically modified insects; symbiosis; microbiome; transgenic; self-limiting; insect rearing; mutualism
Online: 7 March 2019 (14:00:12 CET)
Mass insect rearing can have a range of applications, for example in biological control of insects. Since the performance of released biological control agents determines efficacy, the competitive fitness of insects post release is a key variable. Here, we tested whether inoculation with a gut symbiont, Enterobacter cloacae, and gnotobiotic rearing of larvae could improve insect growth and male competitive fitness of a transgenic diamondback moth, which has shown variation in fitness when reared in different insectaries. All larvae were readily infected with the focal symbiont. Under gnotobiotic rearing pupal weights were reduced and there was a marginal reduction in larval survival. However, gnotobiotic rearing substantially improved the fitness of transgenic males. In addition, in gnotobiotic conditions, inoculation with the gut symbiont increased pupal weights and male fitness, increasing the proportion of transgenic progeny from 20 to 30% relative to symbiont-free insects. Gnotobiotic conditions may improve the fitness of transgenic males by excluding microbial contaminants, while symbiont inoculation could further improve fitness by providing additional protection against infections, or by normalizing insect physiology. The simple innovation of incorporating antibiotic into diet, and inoculating insects with symbiotic bacteria that are resistant to that antibiotic, could provide a readily transferable tool for other insect rearing systems.
ARTICLE | doi:10.20944/preprints201901.0263.v1
Subject: Biology, Entomology Keywords: Tenebrio molitor; suppressor of cytokine signaling; insect immunity; gene expression
Online: 26 January 2019 (02:51:45 CET)
Suppressors of cytokine signaling (SOCS) influence cytokine and growth factor signaling by negatively regulating the JAK-STAT pathway. This maintains homeostasis during host immune response. However, functional characterization of SOCS family members in invertebrates is limited. In this study, we discovered the Type-I subfamily of the SOCS genes in the mealworm beetle, T. molitor. The full-length ORFs of TmSOCS5, TmSOCS6, and TmSOCS7 consisted of 1,389, 897 and 1,458 nucleotides, encoding polypeptides of 462, 297 and 485 amino acids, respectively, The C-terminal region of TmSOCS was highly conserved in the SH2 and SOCS box domains. Phylogenetic analysis revealed that the three SOCS genes clustered within the same sub-family and the highest amino acid identity was with the Tribolium castaneum SOCS genes (TcSOCS). While the expression of TmSOCS5 and TmSOCS6 was low in larval, pupal, and adult stages of the insect, TmSOCS7 showed higher expression. The expression of TmSOCS5 and TmSOCS6 was higher in larval hemocytes and adult ovary. The microbes expressed the three TmSOCS genes to varying degrees. C. albicans elicited the strongest response in the host with highest 15-fold expression in TmSOCS7 3 h post-inoculation. Collectively, these data suggest that the Type I TmSOCS could play a role in eliciting host immunity.
ARTICLE | doi:10.20944/preprints201901.0058.v1
Subject: Biology, Entomology Keywords: Aedes aegypti; Acyrthosiphon pisum; Myzus persicae; Vicia faba; honeydew; honeydew odorants; mosquito sugar feeding; microbe-emitted odorants; mosquito olfaction
Online: 8 January 2019 (10:13:01 CET)
Plant sugar is an essential dietary constituent for mosquitoes, and hemipteran honeydew is one of the many forms of plant sugar important to mosquitoes. Many insects rely on volatile honeydew semiochemicals to locate aphids or honeydew itself. Mosquitoes exploit volatile semiochemicals to locate sources of plant sugar but their attraction to honeydew has not previously been investigated. Here we report the attraction of female yellow fever mosquitoes, Aedes aegypti, to honeydew odorants from the green peach aphid, Myzus persicae, and the pea aphid, Acyrthosiphon pisum, feeding on fava bean, Vicia faba. We used solid phase micro-extraction and gas chromatography – mass spectrometry to collect and analyze headspace odorants from honeydew of A. pisum feeding on V. faba. An 8-component synthetic blend of these odorants and synthetic odorant blends of crude and sterile honeydew that we prepared according to literature data all attracted female A. aegypti. The synthetic blend containing microbial odor constituents proved more effective than the blend without these constituents. Our study provides the first evidence for anemotactic attraction of mosquitoes to honeydew and demonstrates a role for microbe-derived odorants in the attraction of mosquitoes to essential plant-sugar resources.
ARTICLE | doi:10.20944/preprints201812.0334.v1
Subject: Biology, Entomology Keywords: herbicides; insecticides; antagonistic interaction; P450; Helicoverpa armiger
Online: 28 December 2018 (05:27:22 CET)
With the long-term and large-scale use, herbicides have been well known to influence tritrophic interactions particularly natural enemies of pests in agro-ecosystems. On the other hand, herbivorous insects, especially the generalist pests, have developed antagonistic interaction to different insecticides, toxic plant secondary metabolites and even heavy metals. However, whether exposure to herbicides would affect resistance of insects against insecticides is largely unknown, especially in agricultural pests. Here, we first reported that pre-exposure to two widely used herbicides butachlor and haloxyfop-methyl for 48 h can prime resistance of a generalist agricultural pest Helicoverpa armigera Hübner against insecticide methomyl and fungal toxin aflatoxin B1. In addition, there were no significant differences between control and herbicides-treated caterpillars on weight gain, pupal weight and pupation rates, suggesting that exposure to herbicides induce resistance of H. armigera accompanied with no fitness cost. Moreover, by determining detoxifying enzyme activities and toxicity bioassay with additional inhibitor of cytochrome P450 piperonyl butoxide (PBO), we showed that exposure to herbicides might prime P450-mediated detoxification of H. armigera against insecticide. Based on these results, we propose that exposure to herbicides primes resistance of H. armigera against insecticide by eliciting a clear elevation of predominantly P450 monooxygenase activities in midgut and fat body.
ARTICLE | doi:10.20944/preprints201811.0204.v1
Subject: Biology, Entomology Keywords: Petroselinum crispum; Aedes aegypti; enzyme activity; esterases, mixed-function oxidases; phosphatases
Online: 8 November 2018 (10:41:59 CET)
As part of the ongoing screening research for local edible plants in Thailand, Petroselinum crispum fruit oil was considered as a potential bioinsecticide with proven antimosquito activity against both the pyrethroid susceptible and resistant strains of Aedes aegypti. Due to the comparative mosquitocidal efficacy on these mosquitoes, this plant oil is promoted as a natural alternative and attractive candidate for further study in monitoring resistance of mosquito vectors. Therefore, the aim of this study was to evaluate the impact of P. crispum oil on the biochemical characteristics of the target mosquito larvae of Ae. aegypti, by determining quantitative changes of key enzymes responsible for xenobiotic detoxification, including glutathione-S-transferases (GSTs), α- and β-esterases (α-/β-ESTs), acetylcholinesterase (AChE), acid and alkaline phosphatases (ACP and ALP) and mixed-function oxidases (MFO). Three populations of Ae. aegypti, comprising the pyrethroid susceptible Muang Chiang Mai-susceptible (MCM-S) strain and the pyrethroid resistant Pang Mai Dang-resistant (PMD-R) and Upakut-resistant (UPK-R) strains, were used as test organisms. Biochemical study of Ae. aegypti larvae prior to treatment with P. crispum oil revealed that apart from AChE, the baseline activity of most defensive enzymes, such as GSTs, α-/β-ESTs, ACP, ALP and MFO, in resistant UPK-R or PMD-R, was higher than that determined in susceptible MCM-S. However, after 24-h exposure to P. crispum oil, the pyrethroid susceptible and resistant Ae. aegypti showed similarity in biochemical features, with alterations of enzyme activity in the treated larvae, as compared to the controls. A significant increase in the activity levels of GSTs, α-/β-ESTs, ACP and ALP was recorded in all strains of P. crispum oil-treated Ae. aegypti larvae, whereas MFO and AChE activity in these mosquitoes was decreased. The recognizable larvicidal capability on pyrethroid resistant Ae. aegypti, and the inhibitory effect on AChE and MFO, emphasized the potential of P. crispum oil as an attractive alternative application for management of mosquito resistance in current and future control programs.
ARTICLE | doi:10.20944/preprints201811.0159.v1
Subject: Biology, Entomology Keywords: Bombyx mori; BmNPV; antiviral therapeutic; CRISPR/Cas9; multi-gene editing
Online: 7 November 2018 (10:23:52 CET)
Clustered regularly interspaced short palindromic repeats/associated protein 9 nuclease (CRISPR/Cas9) technology guided by a single-guide RNA (sgRNA) has recently opened a new avenue for antiviral therapy. A unique capability of the CRISPR/Cas9 system is multiple genome engineering. However, there are few applications in insect viruses by a single Cas9 enzyme targeting two or more sgRNA at different genomic sites for simultaneous production of multiple DNA breaks. To address the need for multi-gene editing and sustained delivery of multiplex CRISPR/Cas9-based genome engineering tools, we developed a one-vector (pSL1180-Cas9-U6-sgRNA) system to express multiple sgRNA and Cas9 protein to excise Bombyx mori nucleopolyhedrovirus (BmNPV) in insect cells. Here, ie-1, gp64, lef-11, and dnapol genes were screened and identified as multiple sgRNA editing sites according to the BmNPV system infection and DNA replication mechanism. Furthermore, we constructed a multiplex editing vector sgMultiple to efficiently regulate multiplex gene editing steps and inhibit BmNPV replication after viral infection. This is the first report that describes the application of multiplex CRISPR/Cas9 system inhibiting insect virus replication. This multiplex system can significant enable the potential of CRISPR/Cas9-based multiplex genome engineering in transgenic silkworms.
ARTICLE | doi:10.20944/preprints201810.0212.v1
Online: 10 October 2018 (09:49:35 CEST)
Background: Dengue incidence has grown dramatically around the world in recent years. It transmitted by Aedes mosquitoes. Many factors contributed to the vector densities such as environmental and sociological factors. Objective: This study is aimed at determining the environmental and sociological factors contributing to dengue cases. Methods: The study used questionnaire survey involving 379 respondent with dengue history. Result: The study showed that there is significant association between the time departs to work and mobility of respondents (95%CI = 2.779 and 5.594, p < 0.0001). Similarly, there is significant association between the time of arrival to work and mobility of respondents (95%CI = 1.617 and 2.155, p < 0.0001). Moreover, the type of housing and the surrounding vegetation were the environmental factors that showed significant values; p = 0.023, and p = 0.017. Conclusion: The study indicated the factors contributed are patient who lived in independent houses and the time of mobility patient.
ARTICLE | doi:10.20944/preprints201809.0581.v1
Subject: Biology, Entomology Keywords: Frankliniella occidentalis; Lygus hesperus; Trialeurodes vaporariorum; Tetranychus urticae; entomopathogenic fungi; integrated pest management
Online: 29 September 2018 (05:33:45 CEST)
The twospotted spider mite, Tetranychus urticae and the western tarnished plant bug, Lygus hesperus are major arthropod pests of strawberries in California. Other important insect pests include the greenhouse whitefly, Trialeurodes vaporariorum and the western flower thrips, Frankliella occidentalis. Chemical pesticides play a major role in managing these pests, but not without the associated risk of pesticide resistance and environmental safety. Two field studies were conducted in Santa Maria to evaluate the potential of botanical and microbial pesticides in the integrated pest management (IPM) of strawberry. Chemical, botanical, and microbial pesticides were evaluated against T. urticae in a small plot study in 2013 and against L. hesperus and other insect pests in a large plot study in 2015 in commercial strawberry fields. Bug vacuums were also used in the 2015 study. Results demonstrated that non-chemical alternatives can play an important role in strawberry IPM.
ARTICLE | doi:10.20944/preprints201808.0262.v1
Subject: Biology, Entomology Keywords: tomato pest; Tuta absoluta; bioassay; pesticide resistance; LD50; CYP450s
Online: 15 August 2018 (04:24:01 CEST)
In 2016 northern Nigeria experienced a devastating infestation by the tomato leaf miner, leading to soaring in prices of tomato across the country. Unfortunately, information on the bionomics and resistance status of this pest is lacking in northern Nigeria, hampering appropriate control measures. Here, we identified to species level, and using conventional and synergist bioassays characterised pesticides resistance profile of a field population of a tomato leaf miner from northern Nigeria. Highest resistance was obtained with λ-cyhalothrin (Type II pyrethroid) with a low mortality (18.52% at 56hr) and LD50 of 7461.474ppm. Resistance was also established toward propoxur and chlorpyrifos-methyl with average mortalities each of 56% and LD50s of 1023.51ppm and 106.351ppm, respectively. Highest susceptibility was seen with abamectin with mortality of 86% and LD50 of 0.034ppm. Pre-exposure to piperonyl butoxide significantly recovered λ–cyhalothrin susceptibility (mortality = 90% and LD50 = 0.92ppm) implicating the P450 monoxygenases in the resistance. No significant changes in mortalities were obtained on pre-exposure to diethyl maleate and triphenyl-phosphate- inhibitors of glutathione S-transferases and carboxylesterases, respectively. The finding of resistance to these agricultural pesticides will sensitize stakeholders across Nigeria to take action to manage the resistance at an early stage before it gets out of hand.
ARTICLE | doi:10.20944/preprints201806.0087.v1
Subject: Biology, Entomology Keywords: insulin-signaling; insulin receptor; Aedes aegypti; mosquitoes; insulin; insulin-like peptides; nutrition; hyperinsulinemia; larval-diet; metabolic reserves
Online: 6 June 2018 (11:55:53 CEST)
Mosquitoes have distinct developmental and adult life history, and the vectorial capacity of females has been shown to be affected by the larval nutritional environment. However, little is known about the effect of developmental nutrition on insulin-signaling and nutrients storage. In this study, we used Aedes aegypti, the yellow fever mosquito, to determine whether larval nutrition affects insulin gene expression. We also determined the traits regulated by insulin signaling, such as stored-nutrients levels and fecundity. We raised mosquito larvae on two different diets, containing either high protein or high carbohydrates. Development on a high-carbohydrate diet resulted in several life-history phenotypes indicative of suboptimal conditions, including increased developmental time and decreased fecundity. Additionally, our data showed that insulin transcript levels are affected by a high-carbohydrate diet during development. Females, not males, reared on high-carbohydrate diets had much higher transcript levels of insulin-like peptide 3 (ILP3), a mosquito equivalent of human insulin, and these females more readily stored sugar from the meal into lipids. We also found that AaILP4, not AaILP3, transcript levels were much higher in the males after a sugar meal, suggesting sex-specific differences in insulin-signaling pathway. Our findings suggest a conserved mechanism of carbohydrate-mediated hyperinsulinemia in animals.
ARTICLE | doi:10.20944/preprints201805.0270.v1
Subject: Biology, Entomology Keywords: biotrophic interactions; invasive species; colour polymorphism; harlequin ladybird; harmonine
Online: 21 May 2018 (11:41:07 CEST)
Harmonia axyridis is an invasive ladybird (Coleoptera, Coccinellidae) with the potential to outcompete native ladybird species in its invasive distribution area. It was introduced as a biological control agent in many countries but has also spread unintentionally in many others. Hesperomyces virescens (Ascomycota, Laboulbeniales) is a minute (200–400 µm in size) biotrophic fungus that infects over 30 species of ladybirds. The aim of this study was to evaluate whether elytral colour pattern, size, and sex of Ha. axyridis affect infection by H. virescens. Colouration in Ha. axyridis has been linked to the presence of an antimicrobial alkaloid (harmonine). In fall 2016, we collected 763 Ha. axyridis individuals in Cambridge, Massaschusetts, of which 119 (16%) bore H. virescens fruiting bodies. We analysed 160 individuals concerning prevalence and intensity of infection by H. virescens. Elytral sizes and colouration patterns were quantified using digital photography and analytical methods. Smaller ladybirds had a higher prevalence and higher intensity of parasitism. Additionally, male ladybirds bore more thalli compared to female ladybirds. Elytral colour patterns had an effect on neither prevalence nor intensity of infection by Laboulbeniales in our dataset. This suggests that development of Laboulbeniales may be unaffected by certain insect alkaloids.
ARTICLE | doi:10.20944/preprints201805.0186.v1
Subject: Biology, Entomology Keywords: rice landscape; natural enemies; location; population dynamics; variography; LANDSAT 8
Online: 14 May 2018 (10:13:50 CEST)
Relationships among the population abundance of four predator groups for rice insect pests, namely: carabid beetles, staphylinid beetles, green mirid bugs, and spiders in three landscape categories were evaluated. Both rice plots and the associated bund margins of these rice plots found among three Bangladesh landscape categories were sampled by sweep net. The results revealed that the abundance significantly varied across landscapes. The rice landscape of one location harbored higher numbers of a specific predator than other location in other regions of Bangladesh. The results also showed a dependency on the width of the rice bund margins of the rice plots, where spiders populations increased with increased bund widths, but the population abundance of these predators did not depend on the diversity of the number of weed species found on the rice bund margins. The relative abundance of predator populations also significantly differed among the three landscapes, with the green mirid bug having the highest number among the four predators. This study indicates that predators of rice insect pests are highly landscape specific. In order to design integrated pest management systems for different Bangladeshi rice production locales, considerations unique to the characteristics of each locale are necessary. Preliminary efforts to apply variography analyses to the RED spectral band of LANDSAT 8 imagery from December 2016 are presented as first step toward learning a suite of methods which describe useful local characteristics affecting rice pest predators.
ARTICLE | doi:10.20944/preprints201804.0089.v1
Subject: Biology, Entomology Keywords: immune response; lectin; Mirabilis jalapa; phagocytic activity; phenoloxidase; Spodoptera litura
Online: 8 April 2018 (09:39:35 CEST)
Biological control provides a safer alternative to reduce the population of agricultural pest. Mirabilis jalapa is one of biopesticides containing chemical substances that have a feeding deterrent property against Spodoptera litura as folifagus insect pest. This study aimed to analyze the humoral and cellular immunes responses of S. litura after exposure to biopesticide extracted from M. jalapa. The measured indicator immune responses were activity of hemocyte, lectin, phenoloxidase (PO), and phagocytic activity. The results showed that the average total hemocyte was different significantly depending on the treatment. Exposure to 0.1% and 0.2% (w/v) of M. jalapa extract increased the total number of hemocytes as much as 38.08% and 64.15%, respectively. Lectin was quickly formed at 0.1% and 0.2% (w/v) concentrations. The amount of PO enzymes was significantly different at sublethal concentrations compared with control samples (P < 0.05). The highest increase in PO activity occurred at 2 h post-treatment and at M. jalapa extract concentrations of 0.2% (592.33 IU/mg) and 0.1% (521.33 IU/mg), whereas the highest concentration of the extract (0.8% w/v) caused a decrease in lectin and PO activities. In terms of phagocytic activity, the proportion of phagocytosis cells were 47.62% in control group, and decreased significanlty in both concentrations exposure.
ARTICLE | doi:10.20944/preprints201803.0252.v1
Subject: Biology, Entomology Keywords: Curculionidae; Cossoninae; Rhyncolini; Rhyncolina; taxonomy; new species; mature larva; morphology; host plant; Cape Verde; biogeography; microclimate; species competition
Online: 29 March 2018 (14:53:47 CEST)
The genus Aphanommata in the Old World is reviewed. Aphanommata kuscheli sp. nov. from São Nicolau and A. strakai sp. nov. from Fogo (both Cape Verde islands) are described. Aphanommata euphorbiarum (Wollaston, 1867) from Santo Antão in the Cape Verde islands is redescribed and its lectotype is designated. All three Aphanommata species from the Cape Verde islands as well as A. filum (Mulsant & Rey, 1859) from Old World are diagnosed, illustrated, and keyed. Mature larva of A. kuscheli sp. nov. is described, larval morphology is discussed and the current state of knowledge about immature stages of Cossoninae is summarized. Vertical and inter-insular distributional pattern of Cape Verde Aphanommata and Pselactus is reviewed and discussed.
ARTICLE | doi:10.20944/preprints201803.0130.v1
Online: 16 March 2018 (06:56:09 CET)
In this paper we show the results of investigating the presence of organochlorine pesticides in honey and pollen samples from managed colonies of the honey bee, Apis mellifera L. and of the stingless bee Scaptotrigona Mexicana Guérin. We found that 88.44% and 93.33% of honey samples, and 22.22% and 100% of pollen samples of S. mexicana and A. mellifera, respectively, resulted positive to at least one organochlorine. The most abundant pesticides were DDE, DDT, Endrin and heptaclor. Despite the low foraging range of S. mexicana the number of pesticides detected in the honey samples was similar to that of A. mellifera. Paradoxically we a found a small number of organochlorines in pollen samples of S. mexicana, perhaps indicating a rapid turnover of this material as compared to A. mellifera.
ARTICLE | doi:10.20944/preprints201803.0070.v1
Subject: Biology, Entomology Keywords: Aedes aegypti; insecticide resistance; pyrethroid; permethrin; VGSC gene
Online: 9 March 2018 (05:27:12 CET)
Aedes aegypti mosquito is a vector that could transmit various pathogens, such as viruses, bacteria, and parasites. Several human diseases transmitted by Ae. aegypti mosquito are dengue fever (DHF), Chikungunya, Yellow Fever and Zika. The occurance of resistance to various insecticides, including pyrethroid, is a current problem faced by various countries. In this research, a WHO bioassay test on Palembang and Jakarta Ae. aegypti was conducted using 0.25% permethrin pyrethroid insecticide. VGSC gene fragments associated with pyrethroid resistance (L982, S989, I1011, L1014, V1016 and F1534) of resistant and sensitive strains were amplified and analyzed. The test showed the presence of resistance in Ae. aegypti isolates from Palembang and Jakarta. From the results of VGSC gene fragment analyses, it was known that there were mutations (S989P and/or V1016G) on isolates from Palembang and (S989P and/or V1016G) on resistant isolates from Jakarta.
BRIEF REPORT | doi:10.20944/preprints201801.0286.v1
Subject: Biology, Entomology Keywords: volatile fatty acids; Alphitobius diaperinus; locomotor activity; repellency
Online: 30 January 2018 (14:46:51 CET)
Volatile fatty acids (VFAs) are a group of common metabolites with a potential of universal infochemicals dedicated to transferring of information between higher organisms and bacteria either from microbiome or external environment. VFAs are common substances among various insect orders, there are numerous studies exploring their influence on the behavior of different insect species. In relation to papers published by J. E. McFarlane, we assess the effects of formic, acetic, propionic, butyric, valeric acids on spatial preference of common stored food grain products, and poultry industry pest – lesser mealworm (Alphitobius diaperinus). We present novel method of continuous, simultaneous assessment of site preference as well as travelled distance in constant-flow olfactometer. All tested VFAs except valeric had a significant repellent effect with formic acid being effective in the lowest concentration. Additionally, VFAs significantly altered distance travelled by insects. Obtained results indicate a potential role of VFAs in the olfactory guided behavior of A. diaperinus, we speculate that reaction to the presence if VFAs may deviate form specificity of species’ original habitat.
ARTICLE | doi:10.20944/preprints201711.0079.v1
Subject: Biology, Entomology Keywords: DNA barcoding; genetic diversity; hymenopteran parasitoids; Nephotettix spp.; Nilaparvata lugens; rice
Online: 13 November 2017 (17:06:38 CET)
On-going intensification of rice production systems in Southeast Asia is causing devastating yield losses each year due to rice hoppers. Continuing development of immunity to resistant rice varieties and pesticide application further complicate this problem. Hence, there is a high demand for biological control agents. Egg parasitoid wasps are among the most important natural enemies of rice hoppers such as Nilaparvata lugens and Nephotettix spp. However, our knowledge on their diversity is still very limited due to their small size and the lack of available morphological information. Classifying these parasitoids is the first step to properly understand their role in the rice agroecosystem. We used traditional morphological identification as well as DNA sequencing of COI and 28S genes to investigate the diversity of four important hopper egg parasitoid genera in the Philippines. Parasitoids of the genera Anagrus spp., Oligosita spp., Gonatocerus spp. and Paracentrobia spp. were collected in eight study landscapes located in Luzon. We found discrepancies between the morphological and the molecular analysis. Morphological and molecular results were only valid for Paracentrobia spp. Anagrus spp. and Gonatocerus spp. showed more genetic diversity, than expected after the morphological analysis, indicating cryptic species. The sequences for Oligosita spp. revealed less variation than expected. This is the first study on molecular diversity of rice parasitoids in the Philippines. More research combining morphological, behavioural and genetic methods as well as the establishment of a comprehensive DNA database is urgently needed to assess the performance and suitability of these organisms as biocontrol agents.
ARTICLE | doi:10.20944/preprints201703.0211.v1
Subject: Biology, Entomology Keywords: Zika virus; Flavivirus; RNA Viruses; Viruses; surveillance; occurrence; epidemiology; West Nile virus; Aedes; Culicidae
Online: 28 March 2017 (16:38:17 CEST)
In 2015 in Brazil, Zika virus showed features of geographic expansion and potentially increased virulence. In 2016, New York State issued emergency regulations after the World Health Organization declared Zika virus a Public Health Emergency of International Concern. In this study, mosquito surveillance was conducted in Westchester County, New York, to identify Zika virus and other arboviruses. Twenty trap sites were used for surveillance of Aedes albopictus mosquitoes, the Zika virus vector. The Westchester County Department of Health performed testing for Zika, West Nile, Eastern equine encephalitis, and other flaviviruses on 369 batches comprising 8,891 mosquitoes. Aedes albopictus mosquitoes were identified in Nassau, Rockland, Suffolk, Westchester, and New York City. Despite the increased capacity for specimen analysis, Zika virus was not detected. This study provides the first evidence of appropriate Zika virus surveillance. However, the results do not allow determination of the potential mechanism of local vector-to-human transmission of Zika virus among Aedes albopictus mosquitoes. This study adds to the evidence regarding the distribution, emergence, and trapping capabilities of potential Zika virus vectors.
ARTICLE | doi:10.20944/preprints201703.0182.v1
Subject: Biology, Entomology Keywords: Lauxanioidea; Cyclorrhapha; mitochondrial genome; phylogeny; RNAs; intergenic sequences
Online: 24 March 2017 (08:03:42 CET)
The superfamily Lauxanioidea is a significant dipteran clade including over 2500 known species in three families: Lauxaniidae, Celyphidae and Chamaemyiidae. We sequenced the first five (three complete and two partial) lauxanioid mitochondrial (mt) genomes, and used them to reconstruct the phylogeny of this group. The lauxanioid mt genomes are typical of the Diptera, containing all 37 genes usually present in bilaterian animals. A total of three conserved intergenic sequences have been reported across the Cyclorrhapha. The inferred secondary structure of 22 tRNAs suggested five substitution patterns among the Cyclorrhapha. The control region in the Lauxanioidea has apparently evolved very fast, but four conserved structural elements were detected in all three complete mt genome sequences. Phylogenetic relationships based on the mt genome data were inferred by Maximum Likelihood and Bayesian methods. The traditional relationships between families within the Lauxanioidea, (Chamaemyiidae + (Lauxaniidae + Celyphidae)), was corroborated, however, the higher level relationships between cyclorrhaphan superfamilies are mostly poorly supported.
ARTICLE | doi:10.20944/preprints201703.0128.v1
Subject: Biology, Entomology Keywords: Bti-spraying alternative; Camargue; environmental impacts; mosquito control; Techno Bam traps
Online: 17 March 2017 (03:22:05 CET)
We tested the use of mosquito traps as an alternative to insecticide spraying in Camargue (France) following the significant impacts observed on the non-target fauna through Bti persistence and trophic perturbations. In a village of 600 inhabitants, 16 Techno-Bam traps emitting CO2 and using octenol lures were set from April to November 2016. Trap performance was estimated at 70% overall based on mosquito landing on human baits in areas with and without traps. Reduction of Ochlerotatus caspius and Oc. detritus, the two species targeted by Bti spraying, was respectively 74 and 98%. Traps were less efficient against Anopheles hyrcanus (46%), which was more attracted by lactic-acid than octenol lures based on previous tests. Nearly 300 000 mosquitoes from nine species were captured, with large variations among traps, emphasizing that trap performance is also influenced by surrounding factors. Environmental impact, based on the proportion of non-target insects captured, was mostly limited to small chironomids attracted by street lights. Breeding success of a house martin colony was not significantly affected by trap use, in contrast to Bti spraying. Our experiment confirms that deployment of mosquito traps can offer a cost-effective alternative to Bti spraying for protecting local populations from mosquito nuisance in sensitive natural areas.
ARTICLE | doi:10.20944/preprints201702.0027.v1
Online: 9 February 2017 (06:56:39 CET)
Atta capiguara is a grass-cutting ant species frequently found in Cerrado biome. However, little is known about the giant nest architecture of this ant. In this study, we investigated the architecture of three A. capiguara nests from the fragment of cerrado in Botucatu, São Paulo, Brazil. Casts were made of the nests by filling them with cement to permit better visualization of internal structures such as chambers and tunnels. After excavation, the depth and dimensions (length, width, and height) of the chambers were measured. The results showed the typical shape of Atta capiguara nests consisting of mounds of loose soil with unique features resembling a conic section. The fungus chambers were found outside the apparent main part of the nest and were spaced apart and distributed laterally at ground level. The waste chambers were located beneath the largest mound of loose soil. Both the fungus and waste chambers exhibited a sectoral distribution. Our study contributes to a better understanding of the so far unknown nest architecture of the grass-cutting ant A. capiguara.
ARTICLE | doi:10.20944/preprints201609.0021.v1
Subject: Biology, Entomology Keywords: lemongrass oil; Ligusticum chuanxiong oil; Aphis citricola van der Goot; botanical aphicides
Online: 6 September 2016 (11:52:51 CEST)
In order to develop novel botanical insecticides, the joint action of Ligusticum chuanxiong oil (LCO) and lemongrass oil (LO) against Aphis citricola van der Goot was determined systematically indoors and outdoors. The chemical profiles of LCO and LO as determined by gas chromatography- mass spectrometry analysis revealed that main compounds from LCO were Z-Ligustilide (44.58%) and Senkyunolide A (26.92%), and that of LO were geranial (42.16%) and neral (32.58%), respectively. The mixture of LCO and LO showed significant synergy against A. citricola, with a common-toxicity coefficient (CTC) value of 221.46 at the optimal ratio of LCO to LO (4: 1, w/w). Based on the results of solvents and emulsifiers screening, L. Chuanxiong oil · Lemongrass oil 20% emulsifiable concentrate (20% LCO · LO EC) was developed, which was confirmed to meet the requirements of a commercial pesticide by quality test. Field trials indicated that the insecticidal activity of the diluted 20% LCO · LO EC (1000 fold dilution) was comparable to conventional pesticide (20% imidacloprid EC) on A. citricola 7 days after application. Thus, the mixture of LCO and LO has the potential to be further developed as a botanical pesticide.
ARTICLE | doi:10.20944/preprints201608.0203.v1
Subject: Biology, Entomology Keywords: Sitophilus zeamais; COXⅡ; Soluble proteins; Enzyme activity; AITC
Online: 25 August 2016 (10:11:13 CEST)
COX II containing a dual core CuA active site is one of the three core subunits of mitochondrial Cco, which plays a significant role in the physiological process. In this report, the full-length cDNA of COXⅡ gene was cloned from Sitophilus zeamais, which had an ORF of 684 bp encoding 227 amino acids residues. The predicted COXⅡ protein had a molecular mass of 26.2 kDa with pI value of 6.37, and multiple sequence alignment and phylogenetic analysis indicated that Sitophilus zeamais COXⅡ had high sequence identity 78.51% with the COXⅡ of other insect species, especially similarity to sitophilus oryzae. This gene was subcloned into the prokaryotic expression vector pET-32a, and induced by IPTG in E.coli Transetta (DE3) expression system. Finally the COXⅡ with 6-His tag was purified using affinity chromatography with Ni2+-NTA agarose. WB showed the recombinant COXⅡ was about 44 kD, and the concentration of fusion protein was 50μg/mL. UV-spectrophotometer and infrared spectrometer analysis showed that recombinant COXⅡ could catalyze the oxidation of substrate Cytc, and influenced by AITC. It was found that AITC could form a hydrophobic region with COXⅡ protein via molecular docking, besides, a sulfur atom of AITC structure could form a length of 2.9 Å hydrogen bond with Leu-31. These results will provide valuable information for elucidating the role of COXⅡ in Sitophilus zeamais responses to AITC, meanwhile, it will helpful to carry out a point mutation in AITC binding sites for the future research.