Rediscovered frog species exhibits rare behaviour

A Bengaluru-based researcher, Dr K P Dinesh, working on amphibians at the Centre for Ecological Sciences (CES) of Indian Institute of Science (IISc) has found that the newly re-discovered Rhacophorus lateralis – an endangered tree frog species indulges in male-male combat, to attract breeding females – a very rare behaviour among the Indian amphibians.

Distributed in hilly regions of Wayanad, Kodagu and Chikkamagaluru in the Western Ghats, this frog species, belongs to the Rhacophoridae family and is considered endangered. The species is known for its unique single leaf foam nesting behaviour. The species was first discovered in 1883. It was later on believed to be extinct, until the year 2000, when it was discovered in Kodagu district. The same year it was discovered in Wayanad by a few researchers.

There were no reports about its sighting for the next ten years until it was re-discovered in the Chikkamagaluru region in  2010 by Dr K P Dinesh and others. For the first time, the species was sighted in Mudigere in Chikkamagaluru district. Later on, it was photographed by a wildlife enthusiast and photographer Sunil Sachi, in a village called Makonahalli. Sunil also assisted Dinesh in his research.

Scientific data have been gathered for the first time by the duo after a detailed study of behaviourial pattern of this frog species. “This frog is usually sighted at the elevation above 900 -1000 m above sea level. There is no record of this species being sighted 1200 m above sea level,” says  Dr Dinesh, whose research paper titled ‘Combat and Acoustics of the endangered little frog from the Western ghats, India’' has been published in an international journal, Journal of Threatened taxa in May 2015.

During the process of understanding this newly re-discovered frog species, the researchers came across the male-male combat sequence, which is not a common phenomenon among these Indian species. Stating that the males compete with each other in croaking and try to suppress each others calls, Dinesh explained, “We found a male individual was calling from a bush one metre above the ground. Another male, which was sitting in an adjoining bush jumped on to the branch, where the first one was sitting and resumed croaking and a little while later, he went upto the first male and jumped on its back and tried to prevent the first male from croaking. The first male, started kicking the rival with its hind legs to escape from the clasp. In the process, both fell down.”

He referred to another incident where three male frogs were involved in intense combat, falling on each other trying to prevent each other from croaking. According to Dr Dinesh, such kind of male-male combat is very rare among the Indian amphibians. It has been reported only in a particular species Raorchestes bombayensis in 2001.

This is another such significant finding which will aid further studies like understanding complete breeding behaviour.