Abstract: Crickets and bushcrickets of the suborder Ensifera (Order: Orthoptera) are nocturnal singing insects, and they constitute an excellent system to study the evolution of calling songs. Male Ensiferans produce calling songs with specific temporal and spectral features that act as positional advertisements for mates, and female perception of the call and call type preference mediates mate selection. Ensiferan call evolution is constrained by the need for female auditory perception and sexual selection to be tuned to variants in the male calling song, as well as by acoustic space competition and predator pressure. In this thesis, we analyzed the acoustic divergence of katydids using bioacoustics, morphological, ecological, behavioral and genetic approaches. We quantified Ensiferan bioacoustic diversity and seasonal variation in a tropical ecosystem of North-East India, to explore the use of acoustic space and contextualise call divergence. We also focussed on call divergence in two genuses with closely related morphs that showed call type radiation: three cryptic calling morphs of the genus Hexacentrus from two different ecosystems and five cryptic sympatric acoustically diverse calling morphs from the genus Mecopoda. We found considerable bioacoustic divergence and some cryptic speciation, and identified examples of acoustic niche partitioning and acoustic space overlap in the ecosystem.

About the speaker:  She joined the Ashoka University Ph.D. program in 2018. She did her master's from Banaras Hindu University in zoology. Her background was in mammalian endocrinology but decided to shift her genera into behavioral ecology because of her intense interest in in-vivo studies. She was always fascinated by different intra and inter-species interactions in tropical ecosystems. Now She is working on acoustic diversity in paleotropical Ensiferans. In her Ph.D. thesis, she is exploring diversity in calling songs in tropical ecosystems and how call divergence drives speciation. Besides academia, she is always up for wildlife photography, trekking, scuba diving, and exploring different cultures and places.