Rochishnu Dutta

Department: College of Life and Environmental Sciences
Discipline: Biosciences
Research Centre/Unit: Centre for Ecology and Conservation

Project Summary

A probable cryptic species complex of the bushcricket genus Mecopoda found in various sympatric combinations in Southern India consists of five song types based on temporal features of male calls. These five song types were morphologically indistinguishable and no diagnostic character could be found among 75 quantitative and 61 qualitative morphological characters that were used in a previous study. We used landmark-based geometric morphometrics on two external genitalic characters followed by a classification tree forming technique to successfully separate the five song types with high accuracy. Similar statistical analysis on CHC profile data from all the song types was also able to distinguish most of the song types with high accuracy indicating the existence of differences in cuticular hydrocarbon composition among song types. Phonotactic experiments showed that one of the song types was completely isolated from three of the other song types but showed some preference for one song type. Preference for chirp rate, however, failed to explain this incomplete behavioural isolation between the two song types. This study indicates that pre-mating isolation among Mecopoda song types may be sufficiently strong to maintain the population divergence in the wild.

Supervisory Team

Supervisor: Prof. Tom Tregenza