Ecological patterns in the skin microbiota of frogs from tropical Australia.

Keith Christian,Mirjam Kaestli,Karen Gibb,Alea Rose,Chava Weitzman

doi:10.1002/ece3.4518

Keith Christian, Mirjam Kaestli + Show 3 more

Open Access

https://doi.org/10.1002/ece3.4518

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Abstract

The microbiota of frog skin can play an important role in protecting against diseases and parasites. The frog skin microbial community represents a complex mix of microbes that are promoted by the chemical environment of the frog skin and influenced by the animal's immediate past environment. The microbial communities of six species of frogs sampled from the campus of Charles Darwin University (CDU) were more similar within species than between species. The microbiota of the introduced cane toad (Rhinella marina) was most dissimilar among the species. Pairwise comparisons showed that the microbial communities of each species were different, except for the terrestrial Litoria nasuta and the arboreal L. rothii. The microbial communities of the six species were not related to ecological habit (arboreal or terrestrial), and neither was the alpha diversity of the microbes. The core microbes (defined as being on ≥90% of individuals of a species or group) were significantly different among all species, although 89 microbial operational taxonomic units (OTUs) were core microbes for all six species at CDU. Two species, Rhinella marina and Litoria rothii, were sampled at additional sites approximately 10 and 30 km from CDU. The microbial communities and the core OTU composition were different among the sites, but there were nevertheless 194 (R. marina) and 181 (L. rothii) core OTUs present at all three sites. Thus, the core microbiota varied with respect to geographic range and sample size.

Highlights

The moist skin of amphibians supports a diverse array of bacteria that play critical ecological roles, including defense against pathogens
Despite the perturbations resulting from these environmental and biologic factors, species-specific communities persist and are consistent in different locations (McKenzie et al, 2012; Kueneman et al 2013; Walke et al, 2014; Belden et al, 2015) and prolonged captivity (Becker et al, 2014). This apparent homeostasis is consistent with the notion that several characteristics of the amphibian skin select and enhance specific bacteria over others (Rollins- Smith & Woodhams, 2012)
operational taxonomic units (OTUs) were excluded which were not classified as bacteria, occurred in less than 1% of samples, or contained fewer sequences than 0.01% of the total sequence abundance

Summary

| INTRODUCTION

The moist skin of amphibians supports a diverse array of bacteria that play critical ecological roles, including defense against pathogens. Despite the perturbations resulting from these environmental and biologic factors, species-specific communities persist and are consistent in different locations (McKenzie et al, 2012; Kueneman et al 2013; Walke et al, 2014; Belden et al, 2015) and prolonged captivity (Becker et al, 2014) This apparent homeostasis is consistent with the notion that several characteristics of the amphibian skin (epidermal structures, skin peptides, and other mucosal components) select and enhance specific bacteria over others (Rollins- Smith & Woodhams, 2012). To explore the effect of host species, ecological habit, and geographic location on skin microbial community patterns, we further sampled two of the six species from two additional sites at distances of approximately 10 km and 30 km from the main study site

| MATERIALS AND METHODS

Findings

| DISCUSSION