Heat-driven sex reversal in frogs threatens wild populations with earlier extinction

UPDATE - follow-up to Global warming is turning frogs' sex reversal into an extinction risk: Heat-driven sex reversal in agile frogs creates major reproductive hurdles and weaker offspring, pushing vulnerable populations toward faster decline.

The Study in Hungary

Researchers studied agile frogs in Hungary to understand how climate change affects amphibian survival. In these frogs, high heat during the tadpole stage overrides chromosomes, turning genetically female tadpoles into fertile males. Scientists published these findings in Science Advances on September 3.

Mating and Offspring

Wild tests revealed that sex-reversed males made up about 20 percent of wild populations, but accounted for only 4 percent of egg clutches. Offspring of sex-reversed males also showed higher rates of sex reversal at 61 percent, compared to just 17 percent for normal males. These offspring also suffered more from heat and ranavirus infection, a pathogen that can wipe out over 90 percent of tadpoles.

Context

Amphibians are currently the most threatened vertebrates on earth, with roughly 40 percent facing extinction risks. Climate change accelerates these pressures by altering natural sex ratios and compounding disease vulnerabilities in wild habitats.