AUTHOR=Scarberry Nicole , McAdams Zachary L. , Benson Derek , Herrick Jason , Moore Brandon Christopher , Ericsson Aaron C. TITLE=Longitudinal characterization of the captive adult and tadpole Wyoming toad (Anaxyrus baxteri) microbiome JOURNAL=Frontiers in Amphibian and Reptile Science VOLUME=1 YEAR=2024 URL=https://www.frontiersin.org/journals/amphibian-and-reptile-science/articles/10.3389/famrs.2023.1329897 DOI=10.3389/famrs.2023.1329897 ISSN=2813-6780 ABSTRACT=Introduction

At one time thought to be extinct in the wild, the Wyoming toad (Anaxyrus baxteri) is one of the most critically endangered North American amphibian species. Despite approximately 20 years of ex situ breeding and reintroduction programs, this species remains functionally extinct in the wild. There is concern among those working in these programs that individuals bred in captivity fail to develop a microbiome that withstands the stressors of their native habitat following release. In related species, the skin microbiome has been shown to have a defensive function against common pathogens affecting these animals. However, the early-life microbiome of developing tadpoles in this species remains unknown and, therefore, this defensive function is unexplored in the Wyoming toad.

Methods

This study employed 16S rRNA amplicon sequencing to document the baseline microbiome of tadpole and adult Wyoming toads bred for release at Omaha’s Henry Doorly Zoo and Aquarium (Omaha, Nebraska, USA). We characterized the development of the mucosal microbiome in tadpoles and the mucosal and cloacal microbiome of adult toads.

Results

Our results revealed significant differences between tadpole and adult microbiomes, as well as significant sex-dependent differences within the adult Wyoming toads, in terms of richness and composition.

Discussion

These findings have identified the baseline microbiome of this endangered species and variables significantly influencing its composition in captivity. Ongoing studies of the only extant wild population are expected to identify taxa not found in captive toads, and potentially help 100 design husbandry modifications to maximize survivability following reintroduction to the wild.