Female attractiveness modulated by a male-derived antiaphrodisiac pheromone in a

Keywords: antiaphrodisiac Lygus hesperus male accessory gland myristyl acetate spermatophore Males of the plant bug Lygus hesperus prefer to court virgins over recently mated females. Because a male delivers a large spermatophore mass to the female during copulation that contains more than just sperm, we investigated whether males transferred an odorant molecule rendering females less attractive. We found that topical application of homogenates of the spermatophore, or of the male accessory glands (AG) from which this mass is derived, made virgin females less acceptable as potential mates. Additionally , we found that the fatty molecule myristyl acetate is present in male accessory glands and in the seminal receptacles of recently mated females, but is absent in virgin females. The same distribution of myristyl acetate was also found in Lygus elisus and Lygus lineolaris. We hypothesized that myristyl acetate has a repellent effect on L. hesperus males seeking an appropriate mate. Using topically applied synthetic myristyl acetate at biological concentrations, we found that myristyl acetate was as effective as the AG homogenate at reducing the attractiveness of virgin females. Collectively these results indicate that males use myristyl acetate as a seminally transferred antiaphrodisiac for passive mate guarding, and usage of the compound may be widespread among Lygus bug species. The attractiveness of a female to a conspecific male can vary widely depending on her developmental state and the external stimuli to which she has been exposed. In insects, mature, fecund, virgin females are usually the most attractive to potential mates. Many female insects lose this attractiveness either temporarily or permanently after mating (reviewed in Gillot 2003). In some instances, this is an endogenous effect due to a reduction in the release of an attractant sex pheromone (e. or possibly the induced production of a repellent pheromone (Fuyama & Ueyama 1997; Schiestl & Ayasse 2000). In other species, males may release an antisex pheromone during courtship or mating that counteracts the female's sex pheromone (Zhang & Aldrich 2003). These volatile pheromones may mask the female's odour, marking her and the area around her with a scent that is strongly associated with the presence of a male, indicating that she is either guarded or likely to be unreceptive to further courtship attempts. A third mechanism to reduce female attractiveness is by the transfer of a male-derived antiaphrodisiac during copulation (Happ 1969). These pheromonal compounds function by directly signalling males about the mating status …