The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), is an infectious disease responsible for the worldwide decline of amphibian species. To mitigate these declines, it is necessary to identify the various vectors by which the fungus can be transmitted between individuals and populations. The objective of this study was to determine whether adult female mosquitoes can carry and transfer Bd fungal cells. Mosquitoes were exposed to net soaked in a live Bd zoospore suspension to determine whether they are able to externally acquire the fungus. Another group was placed into containers with a sterile and Bd-inoculated agar plate to determine whether mosquitoes could transfer Bd between these surfaces. Bd DNA was found to be present on mosquito legs exposed to inoculated netting and agar plates suggesting that Bd can be transmitted by the mosquito over short distances This is the first study to demonstrate that an insect host may be a mechanical vector of Bd and suggests that we should begin to consider the role of mosquitoes in the dissemination and control of the fungus.

One of the main families of antimicrobial peptides (AMPs) derived from the skin secretions of Hylidae frogs are dermaseptins. Among them, dermaseptin S4 (DS4) is characterized by its broad spectrum of activity against bacteria, protozoa and fungi. This study determined the physicochemical properties of the native peptide DS4(1-28) and its derivatives [DS4(1-28)a and DS4(1-26)a] isolated from the skin of the frog Phyllomedusa sauvagii and examined their antimicrobial properties against two marine pathogenic bacteria (Vibrio harveyi and V. anguillarum). The results indicate that DS4(1-26)a has high bacteriicdal activity against the tested strains and low hemolytic activity (> 30 % lysis at the highest tested concentration of 100 µg mL-1) compared to the other two peptides. In addition, all three peptides affected the membrane and cell wall integrity of both pathogenic bacteria, causing leakage of cellular contents, with DS4(1-26)a having the most severe impact. These properties were corroborated by tansmission electron microscopy and by the variation of cations in their binding sites due to the effect of AMPs. These results suggest that DS4 and its derivatives, particularly the truncated and amidated peptide DS4(1-26)a, could potentially be effective in the treatment of infections caused by these marine pathogenic bacteria. Future experiments are required to validate the use of DS4 in vivo in the prevention of fish bacterial diseases.

Detecting the trends of species and populations is fundamental to identify taxa with high conservation priority. Unfortunately, long-term monitoring programs are challenging and often lacking. The Italian agile frog Rana latastei is endemic to Northern Italy and adjacent countries, is considered vulnerable by the IUCN, and is protected at the European level. However, quantitative estimates of its decline are extremely scarce. In this study, we document the trends in abundance and distribution of Rana latastei within the Monza Park, which currently represents the area closer to the type locality of the species. Wetlands within the park were monitored from 2000 to 2023; counts of egg clutches were taken as a measure of reproductive output and of the abundance of breeding females. In 2000, the species occurred over a significant proportion of the park. Total abundance showed strong yearly variation but remained rather constant from 2000 to 2019. However, Rana latastei disappeared from the park around 2021 and was never detected in 2022-23. The decline is probably related to the joint effect of multiple factors, including the conversion of breeding sites for farming, inappropriate water management, invasive alien species, and severe drought. The local extinction of Rana latastei occurred despite legal protection, highlighting the need for more effective and stringent tools for the conservation of European biodiversity.

Amphibian populations have been globally declining since at least 1990. In temperate forests of eastern North America, vernal pools offer important breeding habitats to many amphibians but are usually not considered for forest management because of their small size and temporary status. Effective monitoring and management of amphibians rely on accurate knowledge of their spatiotemporal distributions, which is expensive to collect due to the amount of fieldwork re-quired. In this study, we tested whether eDNA metabarcoding could identify the same amphibian communities as traditional inventory protocols. We collected eDNA samples in twelve vernal pools in the spring of 2019 and identified their communities by metabarcoding. At each pool, three traditional amphibian inventory methods were used in May and June 2019: call surveys using acoustic recorders, trapping, and active search surveys. In total, 13 amphibian species were detected, most of them being detected by both eDNA and traditional methods. We found that species ecology and behavior are key factors of its detectability by a specific method. As eDNA metabarcoding is comparatively inexpensive and presents a higher repeatability, we conclude that eDNA sampling should be considered for integration as a standard monitoring tool, after an initial assessment of amphibian diversity.

Metamorphosis is a critical process for most anurans to transition from water to land. The appearance of air-breathing lungs occurs during the change in oxygen medium from water to air. Revealing the structural construction and molecular switches of lung organogenesis is essential to understand the realization of air-breathing function. In this study, histology and transcriptomics were combinedly conducted to explore these issues in Microhyla fissipes lungs during metamorphosis. During the pro-metamorphic phase, histological structure improving of the alveolar wall was accompanied by robust substrate metabolism and protein turnover. The lungs, at the metamorphic climax phase, are characterized by an increased number of cilia in the alveolar epithelial cells and collagenous fibers in the connective tissues, corresponding to the transcriptional upregulation of cilia and extracellular matrix-related genes. The post-metamorphic lungs strengthen the contracting function, as suggested by the thickened muscle layer and the upregulated expression of genes involved in muscle contraction. The blood–gas barrier is fully developed in adult lungs whose transcriptional features are tissue growth and differentiation regulation and immunity. Importantly, significant transcriptional switches of pulmonary surfactant protein and hemoglobin facilitate air-breathing. Our results illuminated four key steps of lung development for amphibians to transition from water to land.

Melanophryniscus admirabilis (admirable red-belly toad) is a microendemic and critically endangered species found exclusively along 700 meters of the Forqueta River, in a fragment of Atlantic Forest in southern Brazil. One of the greatest concerns regarding the conservation of this species is the extensive use of pesticides in areas near their natural habitat. In recent years, the adaptation and persistence of animal species in impacted environments have been associated with microbiota. Therefore, the current study aimed to characterize the oral bacterial community of wild M. admirabilis and to address the question of how this community might contribute to toad’s adaptation in the anthropogenic environment and its general metabolic capabilities. In the present study, 11 oral samples collected from wild M. admirabilis were characterized and analyzed via high-throughput sequencing. A total of 181,350 sequences were obtained, resulting in 16 phyla, 34 classes, 39 orders, and 77 families. Proteobacteria dominated (53%) the oral microbiota of toads followed by Firmicutes (18%), Bacteroidetes (17%), and Actinobacteria (5%). No significant differences in microbial community profile from among the samples were reported, suggesting that the dietary restriction may directly influence the bacterial composition. Functional inference of microbiome was performed using PICRUSt2 and important pathways, such as xenobiotic degradation pathways to pesticides and aromatic phenolic compounds were detected, suggesting that the bacterial communities may have important roles in M. admirabilis health and survival in the anthropogenic environment. Overall, our results have important implications for the conservation and management of this microendemic and critically endangered species.

Intergenerational Justice entitles the maximum retention of Earth’s Biodiversity. The United Nations COP 15 committed to the protection of 30% of Earth’s terrestrial environments to provide Biospheric Sustainability. However, proactive amphibian sustainability needs support from amphibian Reproduction Technologies, Biobanking, and Conservation Breeding Programs [RBCs]. These technologies include the reliable practice of stimulation of reproduction and the collection of sperm and oocytes, refrigerated and cryopreserved sperm storage, in vitro fertilization. Emerging technologies promise the perpetuation of species solely from biobanked biomaterials. However, although exemplary national programs for amphibian RBCs are now established in the USA and Australia, these potentials are not fully realised resulting in unacceptable biodiversity loss. To fully realise these potentials an independent and democratic global organisation is proposed to, 1) focus on the bioregions with the highest amphibian biodiversity, 2) maximise regional inclusion in international initiatives, and 3) provide for maximum community engagement and financial resources. We present the first overall multidisciplinary review of amphibian RBCs, including their geopolitical, cultural, and scientific background, along with their development and application to economically, efficiently, and reliably, perpetuate amphibian biodiversity. We provide genetic models, the potential for diploid cell cryopreservation to perpetuate species, along with significant new information on methodologies and techniques, and standardise nomenclature for specificity in publications and media consistency.

Threat assessment is important to prioritize species conservation projects and planning. The taxonomic resolution regarding the status of the “Dryophytes immaculatus group” and the description of a new species in the Republic of Korea resulted in a shift in ranges and population sizes. Thus, reviewing the IUCN Red List status of the three species from the group: D. immaculatus, D. suweonensis and D. flaviventris and recommending an update is needed. While the three species have similar ecological requirements and are distributed around the Yellow sea, they are under contrasting anthropological pressure and threats. Here, based on the literature available, I have applied all IUCN Red List criteria and tested the fit of each species in each criteria to recommend listing under the adequate threat level. This resulted in the recommendation of the following categories: Near Threatened for D. immaculatus, Endangered following the criteria C2a(i)b for D. suweonensis and Critically Endangered following the criteria E for D. flaviventris. All three species are declining, mostly because of landscape changes as a result of human activities, but the differences in range, population dynamics and already extirpated sub-populations result in different threat levels for each species. Dryophytes flaviventris is under the highest threat category mostly because of its limited range, segregated into two sub-populations and several known historical sub-populations are now extirpated. Immediate actions for the conservation of this species are required. Dryophytes suweonensis is present in both the Republic of Korea and the Democratic Republic of Korea and is under lower ecological pressure in DPR Korea. Dryophytes immaculatus is present in the People’s Republic of China, on a very large range despite a marked decline. I recommend joint efforts for the conservation of these species.

Malaria is a prevalent disease in several tropical and subtropical regions, including Brazil, where remains a significant public health concern. Despite control efforts, reintroduction of endemics in areas without cases for decades poses a challenge. To assess factors influencing ma-laria risk, regional outbreak cluster analysis and a spatio-temporal models were developed for the Brazilian Amazon, incorporating climate, land use/cover interactions, endemic bird, and amphibian richness. Results showed that amphibian, bird richness and endemism correlated with a reduction in malaria risk. Presence of forest had a positive effect on risk, but it depended on its juxtaposition with anthropic land uses. Biodiversity and landscape composition, rather than forest formation presence alone, modulated malaria risk in the period. Areas with low en-demic species diversity and high human activity, predominantly anthropogenic landscapes posed high malaria risk. This study underscores the importance of considering the broader eco-logical context in malaria control efforts.