Six types of sensilla were identified on the antennae of male and female Dacus tryoni with scanning electron microscopy: sensilla chaetica were restricted to the scape and pedicel; trichoid types I and 11, basiconic, clavate and styloconic sensilla were restricted to segment 3. Their morphological characteristics and distributions are described.
IntroductionAs part of a study on sexual behaviour in the Queensland fruit fly, Dacus tryoni (Froggatt), efforts are being made to localise and identify the receptors involved in sex pheromone perception. Ablation experiments (Giannakakis and Fletcher 1981) indicated that receptors at several sites including antennae, maxillary palps and ovipositor are involved in sex pheromone perception. As a preliminary to electrophysiological studies, the sensilla on these organs were examined by scanning and transmission electron microscopy. Here we describe the types and distribution of antennal sensilla of male and female D. tryoni, as revealed by scanning electron microscopy.Several types of sensilla have been described from the antennae of other Diptera (Dethier et al. 1963;Lewis 1971; Bay and Pitts 1976;Venkatesh and Singh 1984). No previous studies have been published on Tephritidae and no specific antennal receptors for sex pheromones have so far been identified in Diptera, although they have been identified in several species of Lepidoptera and other insect groups (reviewed by Seabrook 1977).