Insect aggregation pheromones are defined as chemical substances produced by members of one or both sexes that induce members of both sexes to form aggregations (Borden 1984). Aggregation pheromones are typically emitted by and attract adult insects. Interestingly, larvae of the codling moth, Cydia pomonella L. (Lepidoptera: Olethreutidae), seeking pupation sites will aggregate in response to pheromone produced by cocoon-spinning conspecific larvae (Duthie et al. 2003). Such aggregations may be part of a mating strategy in which protandrous males are arrested by sex pheromone emanating from mature female pupae, thus allowing mating to ensue as soon as a female moth ecloses (Duthie et al. 2003). The cocoon-derived pheromone also attracts the specialist prepupal parasitoid Mastrus ridibundus Gravenhorst (Hymenoptera: Ichneumonidae), which “eavesdrops” on pheromonal communication of cocoon-spinning larvae (Jumean et al. 2004).
