Discovery of male acoustic signals in the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae)

Abstract

Courtship-like signals produced by males during mating behavior were recognized for the first time in whiteflies. Synchronous audio-video recordings ascertained that sexually matured males of Trialeurodes vaporariorum (WESTWOOD) produced substrate-borne vibrations by rapidly oscillating their abdomens in a stereotyped rhythm accompanied with a short moving action around the female. Signals were consisted of a sequence of discrete bouts of sounds, and were named "chirps." A chirp was composed of a series of sinusoidal waves divided into several sections called "pulses." A pulse was defined as having a bimodal phase. Pulse intervals varied from 19.9 to 25.8 ms distinguished by small waves of low amplitude. A chirp was composed of 10-20 pulses, varying in number in the courtship progress. Chirp durations varied from 0.62 to 1.44 ms in proportion to the pulse number. Chirp intervals showed no periodicity, varying from 2.45 to 14.4 s. At the final male courting behavior, a persistent, periodically placed wing flicking was substituted for the train of chirps. Prolonged courtship behavior might be due to the necessity of sexual stimulation for female by repeated emission of the male acoustic signals as well as his persistent wing flicking.