Gomez-Mestre, I. | Search bioRxiv

bioRxiv2025

Growth but not corticosterone, oxidative stress or telomere length is negatively affected by microplastic exposure in a filter-feeding amphibian

Microplastics (MPs) are of increasing global concern for species inhabiting aquatic habitats. However, the mechanisms behind animal responses to MPs need comprehensive exploration. Amphibians are the most threatened vertebrate group with most species having a complex life cycle, commonly with an aquatic larval stage. Here, we investigated whether exposure to an environmentally-relevant concentration of MPs affects the growth of filter-feeding larvae of the African clawed frog (Xenopus laevis), and the consequences for their stress physiology (corticosterone (CORT) levels), or health and ageing physiology (oxidative stress and telomere length). We conducted a 3x2 experiment with three levels of fibre exposure (fibres absent -control-, and MP and cellulose fibre treatments), and two stress levels (CORT absent -control-, and CORT present simulating a stressful condition). We observed a negative impact of MP exposure on larval growth; however, this did not alter the CORT levels, oxidative stress or telomere length. Our study shows that realistic concentrations of MPs is not enough to induce major alterations on the stress or health and ageing physiology of a filter-feeding amphibian. Whether compensatory growth responses during the post-metamorphic stages could lead to detrimental effects later in life should be explored in amphibians and other organisms with complex-life cycles.

evolutionary biology↗

bioRxiv2019

Mating strategy is determinant of Adenovirus prevalence in European bats

Adenoviruses are double-strained DNA viruses found in a great number of vertebrates, including humans. In order to understand their transmission dynamics, it is crucial, even from a human health perspective, to investigate how host traits influence their prevalence. Bats are important reservoirs for Adenoviruses, and here we use the results of recent screenings in Western Europe to evaluate the association between characteristic traits of bat species and their probability of hosting Adenoviruses, taking into account their phylogenetic relationships. Across species, we found an important phylogenetic component in the presence of Adenoviruses and mating strategy as the most determinant factor conditioning the prevalence of Adenoviruses across bat species. Contrary to other more stable mating strategies (e.g. harems), swarming could hinder transmission of Adenoviruses since this strategy implies that contacts between individuals are too short. Alternatively, bat species with more promiscuous behavior may develop a stronger immune system. Outstandingly high prevalence of Adenoviruses was reported for the Iberian species Pipistrellus pygmaeus, P. kuhlii and Nyctalus lasiopterus and we found that in the latter, males were more likely to be infected by Adenoviruses than females, due to the immunosuppressing consequence of testosterone during the mating season. As a general trend across species, we found that the number of Adenoviruses positive individuals was different across localities and that the difference in prevalence between populations was correlated with their geographic distances (P. pygmaeus). These results increase our knowledge about the transmission mechanisms of Adenoviruses.\n\nAuthor SummaryAdenoviruses are DNA viruses with a wide range of vertebrate hosts, including humans, causing ocular, respiratory and gastrointestinal diseases. Here, we focus on the prevalence of Adenoviruses in bats, which are known to be natural reservoir of many viruses, using the results of recent screenings for prevalence of these viruses in 33 European bat species. Our aim is to find association between Adenoviruses prevalence and biological and behavioral host traits, considering the heterogeneity both between and within species in order to have a deeper understanding of mechanisms of viral transmission.\n\nOur results highlight the importance of mating strategy: bats species using swarming as mating strategy are less likely to be infected by Adenoviruses. Moreover, we found that locality of capture can explain a higher prevalence of Adenovirus within species. However, no general pattern has been found in the analysis at individual level, suggesting a strong species specificity and complex viral transmission dynamics.

ecology↗

bioRxiv2018

De novo assembly and annotation of the larval transcriptome of two spadefoot toads widely divergent in developmental rate

Introduction Introduction Methods Results and Discussion Conclusion Data and materials References Most amphibian species exhibit a complex life-cycle including two or more life stages separated by an ontogenetic switch point such as hatching or metamorphosis. Adaptations to divergent environments can require the modification of the timing of such switch points and the relative investment in growth and differentiation between subsequent stages [1]. Such alterations of developmental trajectories, however, often have substantial repercussions at several organismal levels, from physiology to morphology and even genomic structure. Adaptive divergence in developmental rate tracking aquatic habitats of different duration in spadefoot toads is a well-known example of this. Spadefoot toads from Europe and ...

genomics↗