Gut microbes help tadpoles cope with climate change

Amphibians are sensitive to temperatures and other environmental factors, much more so than mammals. Without any way to regulate their own body temperatures, frogs, salamanders and the like are at the whim of climatic changes. Scientists at the University of Pittsburgh suspected that gut microbes, important in other aspects of health, might play a role in resilience to temperature in amphibians, and set out to test this idea.   

“As temperatures are warming, if animals are experiencing disruptions in their microbial communities – as we know can happen due to human-caused stress – then that could lead them to not survive as well,” said lead author Samantha Fontaine, a PhD student in the Kenneth P. Dietrich School of Arts and Sciences.

Fontaine reared tadpoles in several different pools consisting of two categories: normal pond water full of microbes and sterilized water with very few microbes. The two water treatments each contained tadpoles raised at different temperatures ranging from 57 to 82 degrees Fahrenheit.  

Unsurprisingly, the tadpoles that lived in the sterilized water had less microbes in their guts. Strangely, these microbe-less tadpoles grew much larger than their counterparts raised in normal pond water. 

Another interesting result of the research is that the tadpoles with microbes were better able to survive higher temperatures, even when the size difference was accounted for.  

“We definitely need more natural experiments to see how this would actually play out in the wild,” said Fontaine. “But this is the first study to show that there’s a connection between heat tolerance and the microbiome” in animals like amphibians.

The research has a practical conservation application, especially as Earth continues to warm and amphibians are increasingly threatened by many anthropogenic causes. 

“The idea of probiotics is really big in the field: Are there microbes that are really important that we can supplement animals with?” said Fontaine. “If so, it’s possible that can help them withstand changes in temperatures more robustly.”

The research is published in the journal Nature Ecology and Evolution.

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By Zach Fitzner, Earth.com Staff Writer