An alternative reproductive tactic: A parasitoid wasp gathers and guards a harem by pheromone-tagging virgins

Alternative reproductive tactics (ARTs) are the outcome of decisions to obtain copulations in reproductive competition. Mating tactics male insects exhibit can be based on their competitive ability, or be dependent on conditions such as a competitive setting and the spatial and temporal distribution of receptive females. When females are clustered and numerous, two or more mating tactics can coexist. We predicted that this concept is applicable to the egg parasitoid wasp Ooencyrtus kuvanae (Hymenoptera: Encyrtidae), because wasps emerge en masse as sexually mature adults from gypsy moth, Lymantria dispar, egg masses. We reveal that male O. kuvanae exhibit two ARTs, a mate-at-once (MAO) tactic, and a harem-gathering and -guarding (HGG) tactic. MAO males invariably and immediately mate females they encounter. HGG males (i) typically mate the first receptive female they encounter, (ii) then find and assess other females, (iii) tag those without prior male contact, and finally (iv) return to, and mate with, all females they themselves have tagged. Females do not incur a direct fitness cost by mating with multiply-mated males. HGG males rely on their speed, unique tag pheromone, and on the females’ rejection of HGG males except the one that pheromone-tagged them. The tagging pheromone mediates mate recognition and assessment.

► Males of the egg parasitoid wasp Ooencyrtus kuvanae exhibit a harem-gathering and guarding (HGG) mating tactic.
► HGG males pheromone-tag untagged virgins for their harem, then return and mate them.
► Tagged females avoid mating with all males, except for the one that tagged them.
► Females do not incur direct fitness costs by mating with multiply-mated males.
► Specimen-specific tagging-pheromone mediates mate recognition and mate assessment.