Sperm limitation affects sex allocation in a parasitoid wasp Nasonia vitripennis

Abstract

Insect reproduction is influenced by various external factors including temperature, a well-studied constraint. We investigated to what extent different levels of sperm limitation of males exposed to different heat stresses (34 and 36 °C) affect females' offspring production and sex allocation in Nasonia vitripennis. In this haplodiploid parasitoid wasp attacking different species of pest flies, we investigated the effect of the quantity of sperm females received and stored in their spermatheca on their sperm use decisions, hence sex allocation, over successive ovipositions. In particular, we compared the sex allocation of females presenting three levels of sperm limitation (i.e., mated with control, 34 °C heat-stressed or 36 °C heat-stressed males) on each host they parasitized. To disentangle the potential reduction of sperm quality after a heat stress exposure from that of sperm quantity, we also explored the clutch size and sex ratio produced by females that were partially sperm limited after copulating with multiply mated males. Independently of their sperm numbers, all types of females produced a similar total number of offspring, but the more limited ones had fewer daughters. Sperm limitation further affected the distribution of daughters' production across time. In addition to constraints acting on female physiology, male fertility should therefore be considered in studies measuring reproductive outputs of insects submitted to heat stresses.

Constrained sex allocation after mating in a haplodiploid thrips species depends on maternal condition

“…This can be attributed to insemination failure, limited sperm quantity and/or quality (King 2000; Boivin 2013; Chirault et al. 2019), male age (Damiens et al. 2003), male body size (Henter 2004), and genetic factors (Khanh et al.…”

Sperm Limitation Produces Male Biased Offspring Sex Ratios in the Wasp, Nasonia vitripennis (Hymenoptera: Pteromalidae)

“…Both patterns are consistent with the hypothesis that sperm limitation may disrupt adaptive sex allocation by female parasitoids. Sperm limitation as a sex ratio constraint has been studied in numerous parasitoid species (e.g., Boivin 2013 , reviewed in Boulton et al 2015 ) including N. vitripennis ( Velthuis et al 1965 ; Boulton and Shuker 2015a , b Chirault et al 2019 ). In laboratory populations, sperm limitation can arise in female wasps when ovipositing on multiple hosts (e.g., 14 per day in King 2000 ), or by mating with males whose sperm quality or quantity has been experimentally altered (e.g., Henter 2004 , Boulton and Shuker 2015b , Martel et al 2016 , Chirault et al 2019 ).…”

“…Sex ratio was fitted to a binomial error distribution and a logit link function. We accounted for individual-level variation by treating female identity as a random effect (following Chirault et al 2019 ). To determine whether certain females had contributed disproportionately to our sex ratio estimates, we partitioned the total variance in the sex ratios of families produced by females into within- and among-female components and examined the fraction of the total variance that existed among females.…”

“…Sperm-limited females in N. vitripennis are known to produce fewer daughters in primary ovipositions ( King and D’Souza 2004 , Boulton and Shuker 2015b , Chirault et al 2019 . However, this form of disrupted or ‘constrained’ sex allocation is thought to be rare in natural populations where mating occurs locally, because strongly male-biased sex ratios would seldom maximize the number of daughters produced by each brood ( Hardy and Godfray 1990 , Hardy 1994 , King and D’Souza 2004 , Boivin 2013 ).…”

Female Mating Frequency and Reproductive Fitness in the Willow Leaf Beetle (Coleoptera: Chrysomelidae)

“…The hypotheses used to explain the adaptive value of multiple mating can be divided into two general classes: nongenetic benefits (direct/first generation) (Arnqvist and Nilsson 2000) and genetic benefits (indirect/second genetation) (Jennions and Petrie 2000). Sperm limitation may affect female sex allocation and offspring production (Wang et al 2018, Chirault et al 2019). If a female receives insufficient sperm from one mating, then additional matings will help ensure that all eggs are fertilized and provide a fecundity benefit (Olsson and Shine 1997).…”