ABSTRACT

Mate–finding in the large majority of moths is mediated by a long–distance response of males to minute quantities of pheromone emitted by females. Additionally, in many species, males may produce their own pheromone, which is employed after the sexes are brought together. More rarely, males produce acoustic signals and/or a long–distance pheromone. In the latter case, females assume the searching role. The female pheromone systems of the Heteroneura, a group that makes up 99% of extant Lepidoptera, may have had a single origin with relatively little change occurring subsequently, either in the types of chemicals used or in the glandular structures for pheromone production and release. In addition, female signaling appears to be a plesiomorphic trait for the Lepidoptera that likely was lost independently several times among the primitive groups. Recent research points to the female sternum V gland (located on the fifth abdominal sternum), found throughout primitive Lepidoptera, as the most likely evolutionary predecessor of the heteroneuran sexpheromone system. This gland, which is shared with the sister group Trichoptera, also appears to play a defensive role in some species of the two orders. In contrast to the conservation of female pheromone systems, the incidence of male pheromones in moths is exceedingly polyphyletic and labile, suggesting intense and repeated selection for a transient function. Male acoustic signaling, although less prevalent, also appears to have had multiple origins.