Communicating male size by tremulatory vibration in a Columbian rainforest katydid, Gnathoclita sodalis (Orthoptera, Tettigoniidae)

In the South American rainforest katydid Goadiodito sodalis (Orthoptera, Tettigonidae), bouts of acoustic (airborne) and vibratory (substrate-borne) signals occur in the context of male agonistic interactions. We characterized the physical form for both sound and substrate signals and evaluated their role in male male interactions. In a tournament design larger males retained sites against smaller opponents: the probability of winning was predicted by both male size and the incidence of tremulating vibrations. Substrate signaling by long-bodied rainforest katydids is a widespread and important modality of communication which embraces both female attraction and male rivalry.