Andaman Islands: The ‘upside-down’ sex life of a rare Indian frog revealed

“Also, all these fights are taking place in a small tree cavity filled with small quantities of rainwater, unlike in most other species where fights are known to occur in larger open water bodies. It is amazing how frogs have evolved such unique strategies,” he adds.

The study suggests that upside-down mating behaviour evolved to prevent aggressive bachelor males from disrupting egg-laying by displacing the mating pair.

“This find is an example of the remarkable diversity of amphibians and reproductive behaviours that are still unknown to science, especially from unexplored regions in biodiversity hotspots of tropical Asia,” says James Hanken of Harvard University, who was part of the study.

The Charles Darwin frog, named after the famous naturalist, is endemic to a few islands in the Andaman islands and is not found anywhere else. It’s uncommon and restricted to specific forest habitats and listed as “vulnerable” by the International Union for Conservation of Nature (IUCN) due to fragmented populations and habitat decline.

The scientists observed the frogs breeding in disturbed forests in artificial sites – from watered plastic sapling bags in neighbouring plant nurseries to rain-filled discarded containers left as trash at the edge of the forest.

“The frogs’ use of trash for breeding is both surprising and worrying. We now need to know its causes and long-term consequences, and devise ways to protect the natural breeding sites that are critical for survival of the species,” says Sonali Garg, a fellow at Harvard University who co-led the study.

The lack of adequate breeding sites due to habitat loss and competition for limited resources may be driving the frog to breed in such unnatural sites, say researchers.

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