COURTSHIP COMMUNICATION IN MEADOW KATYDIDS - FEMALE PREFERENCE FOR LARGE MALE VIBRATIONS

Males of the katydid Conocephalus nigropleurum (Orthoptera: Tettigonii dae) shake their body to produce a substrate-borne vibratory signal in the context of courtship and mate attraction. We measured the physica l parameters of this tremulation signal and then tested its effectiven ess in eliciting taxis by virgin females. We also investigated the rol e of these vibrations in the choices made by females of larger males a s mates, A search for correlations between male weight and vibratory s ignal parameters revealed a strong negative relationship to inter-puls e interval (ipi). In two-choice playback experiments females oriented towards tremulation vibration when it was the only vibration stimulus provided. In further playback experiments females also distinguished c onspecific tremulation from a control vibration. When offered simultan eous presentations of tremulation signals that differed in ipi, female s moved toward the stimulus with the shorter ipi indicative of a large r male, This is the first study to demonstrate that tremulation signal ling by male katydids encodes critical information on body size, and t hat females discriminate among different vibratory signals in favour o f those indicating a larger male.