Virgins in the wild: mating status affects the behavior of a parasitoid foraging in the field

Abstract

In haplodiploid organisms, virgin females can produce offspring, albeit only sons. They may therefore face a trade-off between either: (1) searching for hosts and producing sons immediately; or (2) searching for mates and perhaps producing both sons and daughters later in life. Although this trade-off raises a theoretical interest, it has not been approached experimentally. The objective of this article is thus to document the effect of mating status on the foraging behavior of a haplodiploid parasitoid. For this, we recorded the behavior of virgin and mated female Lysiphlebus testaceipes (Hymenoptera: Braconidae) after being released, in the field, on a colony of their aphid hosts. Half of the virgin females were mated by a wild male after less than 10 min of foraging. Evidently, virgin females attract males while foraging on host patches, so that the two activities are not mutually exclusive. Nonetheless, virgin females stayed motionless more often and for longer periods than mated females. Consequently, they attacked aphids at a lower rate, and in turn, attacked fewer aphids on each patch. Moreover, contrary to mated females, virgins did not aggregate their progeny on large patches. We conclude that in L. testaceipes, the trade-off may not be as hypothesized. By dispersing across patches more than mated females, virgins could promote future mating opportunities for their sons and increase their inclusive fitness. However, by moving too frequently, females may lose immediate mating opportunities for themselves and the immediate advantage of producing offspring of both sexes. The observed behavior of virgin L. testaceipes females on host patches could reflect an optimal solution to such a trade-off.

Host-Parasitoid Dynamics and the Success of Biological Control When Parasitoids Are Prone to Allee Effects

“…This genetic feature is important in the context of mate-finding Allee effects because it allows females to reproduce even if they do not mate: virgin females can produce males parthenogenetically by laying unfertilized eggs. Consequently, whereas a mate-finding Allee effect decreases the mean fecundity in diploid species, it produces a sex ratio shift toward males in haplodiploid ones (assuming that the fecundities of mated and unmated females do not differ [39], [40], [41], [42], [43]). Hence, it is generally accepted that haplodiploidy prevents or alleviates the demographic consequences of mate-finding Allee effects for free-living organisms [8], [44].…”

Female-Released Sex Pheromones Mediating Courtship Behavior inLysiphlebus testaceipesMales

“…The influence of the female mating status on the male attraction and foraging behavior was also highlighted; in laboratory, males were significantly more attracted to virgin females than to mated females when bioassayed in a Y -tube olfactometer (Lo Pinto et al 2002). In field, virgin females stayed motionless more often and for longer periods than mated females, and attacked aphids at a lower rate (Fauvergue et al 2008). …”

Female‐biased sex ratio shifts in a solitary parasitoid and their effects on virginity, population dynamics, and biological control

“…Although there are some exceptions (Fauvergue et al, 1998(Fauvergue et al, , 2008King, 2002;Metzger et al, 2008), the effects of virginity, especially on populations of solitary parasitoids, have not been considered in great depth [see Stone et al (2009) for analagous work on mosquitoes]. Much of this lack of depth may be due to the difficulties in assessing levels of virgin oviposition in the field.…”

“…Much of this lack of depth may be due to the difficulties in assessing levels of virgin oviposition in the field. As virgin females could be seeking mating opportunities, rather than seeking to oviposit, the number of virgins in a population at any given time does not necessarily represent an accurate measurementofvirginoviposition (Godfray&Hardy,1993;Fauvergue et al, 2008). When attempting to assess virgin oviposition of solitary parasitoids in the field, however, simply surveying the number of virgins in a population is not sufficient.…”

“…This can be most easily assessed in species of Hymenoptera whose mating is constrained to the natal patch, such as fig wasps (West et al, 1998) and many gregarious parasitoids (Kapranas et al, 2011). In addition, mate-seeking and host-searching behaviours may not be mutually exclusive activities (Fauvergue et al, 2008). As virgin females could be seeking mating opportunities, rather than seeking to oviposit, the number of virgins in a population at any given time does not necessarily represent an accurate measurementofvirginoviposition (Godfray&Hardy,1993;Fauvergue et al, 2008).…”