Host Availability Differentially Modulates the Life‐History and Reproduction of Mated and Unmated Females in Two Drosophila Parasitoid Species

ABSTRACT Parasitoid wasps can lay unfertilized eggs that develop into male offspring prior to mating. While most studies investigated the fitness of unmated oviposition under fixed host abundance, the costs and benefits of oviposition before mating may shift at low and high host availability. Furthermore, these studies typically focus on single parasitoid species, which limits their ability to explain patterns in broader parasitoid community structure. We compared differences in multiple life‐history traits and reproductive outcomes under varied host availability between mated and unmated females of two Drosophila parasitoids. Our results revealed key interspecific differences. Firstly, under sucrose‐fed conditions, mated Trichopria drosophilae Perkins (Hymenoptera: Diapriidae) females outlived unmated ones, whereas mated Pachycrepoideus vindemiae Rondani (Hymenoptera: Pteromalidae) females lived shorter than unmated ones. Secondly, when fed with pure water, mated T. drosophilae females survived for a shorter period than unmated females, whereas in P. vindemiae , unmated females survived longer than mated ones only under low host availability. Thirdly, fecundity of female T. drosophilae was unaffected by mating status, but mated P. vindemiae produced substantially fewer offspring than unmated ones. This may reflect altered reproductive allocation after mating in P. vindemiae , whereas unmated females produce only male offspring. Fecundity increased with host availability for both species. The divergence in how mating status affects the life‐history traits of two parasitoid species reflects their different reproductive allocation strategies, with reproductive responses further modulated by host availability. Our study underscores the need for broader research on unmated oviposition behavior across parasitoid species, as this reproductive strategy may influence offspring sex allocation, population dynamics, and biological control efficacy, with important ecological and evolutionary consequences under natural conditions.