Reproductive strategies of the larval parasitoid Microplitis croceipes

Abstract

Mate choice may have important consequences for offspring sex ratio and fitness of haplodiploid insects. Mate preference of females of the solitary larval parasitoid Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) for virgin and mated males, and vice versa, and the reproductive consequences (i.e., the sex ratio expressed as the proportion of male offspring) were examined in choice and non-choice experiments. In addition, the effect of repeated rapid and daily copulation of an individual male on the sex ratio of offspring of the female mates was assessed. Males preferred virgins over mated females, whereas females copulated with a male irrespective of his mating status. In both the rapid and daily copulation assay, females copulating with a male that had copulated five times or more produced a higher sex ratio than females that had copulated with a virgin male. Females that copulated with virgin males once or twice produced a significantly and considerably lower sex ratio than females that first copulated with a sperm-depleted male followed by a virgin male. This indicates that copulating with a sperm-depleted male has costs and limits acquisition by the female of sperm from virgin males.

Reproductive biology of Trichopria anastrephae Lima (Hymenoptera: Diapriidae), a biological control agent of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae)

“…When males are given the chance to mate with several females, rst-mated females produce more female-biased offspring compared to subsequently mated ones. This is consistent with results obtained for other parasitoids (Kant et al 2012, Makatiani et al 2013, and suggests a decrease in sperm transferred after each copulation (Damiens and Boivin 2005). In our experiment, females were replaced right after successful mating by a virgin female, encouraging males to successively mate in a short period.…”

“…However, females that mate with experienced males may receive fewer sperm, and then, produce a higher proportion of male offspring (Steiner et al 2008, Kant et al 2012). To avoid or minimize any negative consequences of mating, females of some species may mate with different males (polyandry) (Makatiani et al 2013). Although monoandry is most common for parasitoid species (Ridley 1993), there is a tendency for gregarious and quasi-gregarious species to be polyandrous (Godfray 1994, Santolamazza-Carbone and Pestaña, 2010).…”

“…Another reproductive strategy is based on the number of matings that both sexes perform in a given period (Thornhill and Alcock 1983). In most parasitoid species, males mate more than once (polygyny) (Makatiani et al 2013). The experience gained after repeated matings, allow males of some hymenopteran wasps to respond and court more successfully than females (Perez-Lachaud and Campan 1995, He and Wang 2008).…”

“…The success of mating strategies in parasitoids is often perceived in the sex ratio of the offspring since unsuccessful matings or insu cient sperm transferred during mating will result in male-biased progeny in arrhenotokous species. Thus, studying mating strategies used by parasitoids is important to improve laboratory mass rearing and increase the success of eld releases (Makatiani et al 2013), since femalebiased offspring is favorable for biological control due to increased population growth rates and female contribution to pest mortality (Heimpel and Lundgreen 2000, Ramadan and Wang 2021). Here, we determined mating strategies used by Trichopria anastrephae Lima (Hymenoptera: Diapriidae), a potential biological control agent against the invasive pest species Drosophila suzukii Matsumura (Diptera: Drosophilidae) (Garcia et al 2022).…”