title: In the nick of time: males of the parasitoid wasp Pimpla disparis respond to semiochemicals from emerging mates.
abstract: Males of the parasitoid wasp Pimpla disparis Viereck (Hymenoptera: Ichneumonidae) aggregate on parasitized gypsy moth, Lymantria dispar, host pupae when the emergence of a prospective mate is imminent or under way. We tested the hypotheses that the developing parasitoid ("DePa") inside the host pupal case produces a pheromone that attracts and arrests mate-seeking males, and that the pheromone is most effective during the emergence of the parasitoid from the host. Results obtained in two-choice laboratory experiments, with 4-7-d-old virgin males, indicate that (1) DePa-derived semiochemicals arrest males, (2) the opening of a host pupal case strongly arrests males, and (3) the arrestment cue emanates from oral fluid secreted by both female and male parasitoids while they chew their way out of a host pupal case. This phenomenon implies that emerging females, which are haplodiploid and can reproduce without mating, do not engage in active pheromone signaling to attract males, and that mate-seeking males co-opt chemicals involved in eclosion as a mate-finding cue, taking a 50% chance that the prospective mate is a female.
authors.affiliation: Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Hrabar
authors.forename: Adela
authors.initials: A
authors.lastname: Danci
authors.forename: Paul W
authors.initials: PW
authors.lastname: Schaefer
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gries
mesh_terms: D000818:Animals; D005260:Female; D006790:Host-Parasite Interactions; D008297:Male; D009036:Moths / Q000469:parasitology*; D010675:Pheromones / Q000378:metabolism*; D011679:Pupa / Q000469:parasitology; D014863:Wasps / Q000502:physiology*
chemical_list: D010675:Pheromones