The communication system in the order Orthoptera (crickets, katydids, grasshoppers) consists of stationary males broadcasting species-specific acoustic signals which are used by females in conspecific recognition and localisation. Some species show deviation from this behaviour, engaging in duetting, with females also contributing to the signal repertoire and the males actively contributing to localisation. A unique duetting system was recently discovered in a katydid species Onomarchus uninotatus, where the females reply to a male’s call with vibratory signals and the male localises females using the vibrations. Laboratory experiments establish vibratory signals to be an immediate response to male calls even at the threshold of female hearing. This presents a paradox as the species is a canopy insect which limits the range of communication through vibratory signals. This is the first known case of female tremulation in response to the male acoustic call being used as a long-range signal. I plan to investigate the functioning of this multimodal duetting in the wild and the factors that could have led to the evolution of such a communication system.

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Abstract