Species-specific close-range sexual communication systems prevent cross-attraction in three species of Glyptapanteles parasitic wasps (Hymenoptera: Braconidae)

The braconid parasitoids Glyptapanteles indiensis (Marsh) and G. liparidis (Bouché) occur in sympatry and allopatry, respectively, with their congener G. flavicoxis (Marsh). We tested the hypothesis that all three parasitoids, but particularly sympatric G. indiensis and G. flavicoxis, use species-specific sex pheromone blends for close-range sexual communication. In coupled gas chromatographic–electroantennographic detection (GC–EAD) analyses of body extracts of conspecific females, male G. indiensis antennae responded to five components, one of which is specific to G. indiensis, and four are in common with G. flavicoxis. Male G. liparidis antennae responded to six components, two of which are specific to G. liparidis, and four are in common with G. flavicoxis. In Y-tube olfactometer experiments, body extracts of females elicited close-range attraction and wing-fanning responses only by conspecific but not by heterospecific males, supporting the hypothesis of close-range species-specific sex pheromone blends.