Intraspecific Variation in the Skin-Associated Microbiome of a Terrestrial Salamander
Resident microbial communities living on amphibian skin can have significant effects on host health, yet the basic ecology of the host-microbiome relationship of many amphibian taxa is poorly understood. We characterized intraspecific variation in the skin microbiome of the salamander Ensatina eschscholtzii xanthoptica, a subspecies composed of four genetically distinct populations distributed throughout the San Francisco Bay Area and the Sierra Nevada mountains in California, USA. We found that salamanders from four geographically and genetically isolated populations harbor similar skin microbial communities, which are dominated by a common core set of bacterial taxa. Additionally, within a population, the skin microbiome does not appear to differ significantly between salamanders of different ages or sexes. In all cases, the salamander skin microbiomes were significantly different from those of the surrounding terrestrial environment. These results suggest that the relationship between E. e. xanthoptica salamanders and their resident skin microbiomes is conserved, possibly indicating a stable mutualism between the host and microbiome.
KeywordsAmphibian Microbiome Symbiosis Ensatina eschscholtzii
The authors would like to thank S. Ellison for his great help with lab work and troubleshooting. We would also like to thank F. Cipriano and A. Swei for advice on methodology. J. de la Torre provided valuable advice as a member of SPI’s Master’s thesis committee. SPI would also like to thank her classmates from OEB210 for valuable feedback on the manuscript. We would also like to thank four anonymous reviewers whose comments greatly improved the manuscript. The National Science Foundation provided funding through a research grant (IOS-1258133) awarded to AGZ and VTV as well as a GRFP (DGE-1144152) awarded to SPI. The National Institutes of Health also provided financial support through MBRS-RISE fellowships awarded to SPI and AKB (R25-GM059298).
Compliance with Ethical Standards
All procedures performed with live animals in this study were approved by the Institutional Animal Care and Use Committee at San Francisco State University (Protocol no. A12-07). All sampling of wild salamanders was performed with approval from the California Department of Fish and Wildlife (SC-12920) and California State Parks.
Conflict of Interest
The authors declare that they have no conflict of interest.
- 16.Walke JB, Becker MH, Loftus SC et al (2014) Amphibian skin may select for rare environmental microbes. ISME J 1–11Google Scholar
- 22.Houck LD, Arnold SJ (2003) Courtship and mating behavior. In: Reprod Biol Phylogeny Urodela, pp 383–424Google Scholar
- 24.Kueneman JG, Woodhams DC, Van Treuren W, et al (2015) Inhibitory bacteria reduce fungi on early life stages of endangered Colorado boreal toads (Anaxyrus boreas). ISME J 10:1–11Google Scholar
- 29.Stebbins RC (1954) Natural history of the salamanders of the plethodontid genus Ensatina. University of California PressGoogle Scholar
- 42.Walke JB, Becker MH, Hughey MC et al (2015) Most of the dominant members of amphibian skin bacterial communities can be readily cultured. Appl Environ Microbiol AEM. 01486–15Google Scholar
- 45.Savage K (2015) Comparative analysis of anti-Bd bacteria from six Malagasy frog species of Ranomafana National ParkGoogle Scholar
- 48.Sabino-Pinto J, Bletz MC, Islam MM et al (2016) Composition of the cutaneous bacterial community in Japanese amphibians: effects of captivity, host species, and body region. Microb Ecol. doi: 10.1007/s00248–016–0797-6
- 49.Murray R, Brenner DJ, Bryant MP (1984) Bergey’s manual of systematic bacteriology. Williams and WilkinsGoogle Scholar
- 65.Rebollar EA, Simonetti SJ, Shoemaker WR, Harris RN (2016) Direct and indirect horizontal transmission of the antifungal probiotic bacterium Janthinobacterium lividum on green frog (Lithobates clamitans) tadpoles. Appl Environ Microbiol AEM 04147–15Google Scholar