Antennal receptor response to sex pheromone mimics in the American cockroach

Abstract

THE essential oils D-bornyl acetate, α- and β-santalol and several plant sesquiterpene hydrocarbons have been shown to induce sexual excitement in male American cockroaches¹, and thus seem to mimic the cockroach sex pheromone. Tahara et al.² have identified one of the active sesquiterpene hydrocarbon species obtained from Compositae plants as germacrene D. The contrast in structures of these various active compounds poses a serious problem as to the specificity of the sex pheromone receptor. To resolve this we have undertaken an electrophysiological study of the antennal receptors of both male and female cockroaches. The electroantennogram (EAG) responses of both sexes were examined during exposure to the compounds in question. Theoretically the sex specific receptors of the male antennae should respond singularly to natural sex-pheromone (and stereochemical mimics) whereas the female antennae should be unresponsive other than to general irritants and/or to food odours. In fact, the EAG response to the female sex attractant has been obtained in males but not in females^3,4.