Biology subjects

Wuster, W.

Publications and source records attributed to Wuster, W..

4 recordsLinked to original sources

bioRxiv2026

Winter warming shapes gut microbiome composition and directional dysbiosis in a temperate lizard

Environmental temperature shapes ectotherm gut microbiomes through direct effects on community structure and indirect effects mediated by host physiology. Due to climate change, winter temperatures are rising, in some regions faster than summer temperatures. However, warming effects on the microbiome during overwintering remain poorly understood compared to the active season, limiting predictions of host-microbiome responses across the annual cycle. We experimentally tested how winter warming influences gut microbiome diversity and composition in the common wall lizard (Podarcis muralis). Thirty-nine lizards were overwintered under cold (4{+/-}1{degrees}C), mild (8{+/-}1{degrees}C), or fluctuating (5 days cold, 2 days mild) temperatures, and 80 faecal samples were collected post-emergence for 16S rRNA gene sequencing. Winter warming did not alter alpha diversity but induced consistent shifts in community composition relative to the cold treatment, with distinct responses to constant versus fluctuating warming. Constant mild temperatures enriched fewer taxa, including putatively opportunistic or pathogenic genera, potentially signalling microbiome imbalance. In contrast, fluctuating warming and the baseline cold treatment preserved a broader suite of fermentative bacteria, likely supporting more stable gut homeostasis. Both warming treatments increased directional dysbiosis relative to the cold treatment, though without increasing interindividual variability, indicating structured reassembly rather than stochastic change. Our findings suggest that winter warming can subtly negatively affect gut microbiomes and host health, while fluctuating temperatures may buffer negative effects. We show that overwintering is an important, yet overlooked, period through which climate warming can shape host-microbiome dynamics.

ecology↗

bioRxiv2021

How do King Cobras move across a major highway? Unintentional wildlife crossing structures may facilitate movement.

O_LIGlobal road networks continue to expand, and the wildlife responses to these landscape-level changes need to be understood to advise long-term management decisions. Roads have high mortality risk to snakes because snakes typically move slowly and can be intentionally targeted by drivers. C_LIO_LIWe investigated how radio-tracked King Cobras (Ophiophagus hannah) traverse a major highway in northeast Thailand, and if reproductive cycles were associated with road hazards. C_LIO_LIWe surveyed a 15.3km stretch of Highway 304 to determine if there were any locations where snakes, and other wildlife, could safely move across the road (e.g., culverts, bridges). We used recurse analysis to detect possible road-crossing events, and used subsets of King Cobra movement data to create dynamic Brownian Bridge Movement Models (dBBMM) in an attempt to show movement pathways association with possible unintentional crossing structures. We further used Integrated Step Selection Functions (ISSF) to assess seasonal differences in avoidance of major roads for adult King Cobras in relation to reproductive state. C_LIO_LIWe discovered 32 unintentional wildlife crossing locations capable of facilitating King Cobra movement across the highway. Our dBBMMs failed to show if underpasses were being used by telemetered individuals; however, the tracking locations pre- and post-crossing provided strong evidence of underpass use. Our ISSF suggested a lower avoidance of roads during the breeding season, though the results were inconclusive. With the high volume of traffic, large size of King Cobras and a 98.8% success rate of crossing the road in our study, we strongly suspect that individuals are using the unintentional crossing structures to safely traverse the road. C_LIO_LIFurther research is needed to determine the extent of wildlife underpass use at our study site and globally, alongside using previously proven fencing to facilitate their use. We propose that more consistent integration of drainage culverts and bridges could help mitigate the impacts of roads on some terrestrial wildlife, particularly in areas where roads fragment forests and wildlife corridors. C_LI

ecology↗

bioRxiv2018

When one phenotype is not enough - divergent evolutionary trajectories govern venom variation in a widespread rattlesnake species

Understanding the relationship between genome, phenotypic variation, and the ecological pressures that act to maintain that variation, represents a fundamental challenge in evolutionary biology. Functional polymorphisms typically segregate in spatially isolated populations [1, 2] and/or discrete ecological conditions [3-5], whereas dissecting the evolutionary processes involved in adaptive geographic variation across a continuous spatial distribution is much more challenging [6]. Additionally, pleiotropic interactions between genes and phenotype often complicate the identification of specific genotype-phenotype links [7-8], and thus of the selective pressures acting on them. Animal venoms are ideal systems to overcome these constraints: they are complex and variable, yet easily quantifiable molecular phenotypes with a clear function and a direct link to both genome and fitness [9]. Here, we use dense and widespread population-level sampling of the Mohave rattlesnake, Crotalus scutulatus, and show that genomic structural variation at multiple loci underlies extreme geographic variation in venom composition, which is maintained despite extensive gene flow. Unexpectedly, selection for diet does not explain venom variation, contrary to the dominant paradigm of venom evolution, and neither does neutral population structure caused by past vicariance. Instead, different toxin genes correlate with distinct environmental factors, suggesting that divergent selective pressures can act on individual loci independently of their genomic proximity or co-expression patterns. Local-scale spatial heterogeneity thus appears to maintain a remarkably ancient complex of molecular phenotypes, which have been retained in populations that diverged more than 1.5-2 MYA, representing an exceptional case of long-term structural polymorphism. These results emphasize how the interplay between genomic architecture and spatial heterogeneity in selective pressures may facilitate the retention of functional polymorphisms of an adaptive phenotype.

evolutionary biology↗

bioRxiv2018

Microbial adaptation to venom is common in snakes and spiders

Animal venoms are considered sterile sources of antimicrobial compounds with strong membrane disrupting activity against multi-drug resistant bacteria. However, bite wound infections are common in developing nations. Investigating the oral and venom microbiome of five snake and two spider species, we evidence viable microorganisms potentially unique to venom for black-necked spitting cobras (Naja nigricollis). Among these are two venom-resistant novel sequence types of Enterococcus faecalis; the genome sequence data of these isolates feature an additional 45 genes, nearly half of which improve membrane integrity. Our findings challenge the dogma of venom sterility and indicate an increased primary infection risk in the clinical management of venomous animal bite wounds. One Sentence SummaryIndependent bacterial colonization of cobra venom drives acquisition of genes antagonistic to venom antimicrobial peptides.

microbiology↗