Variation in lipid synthesis, but genetic homogeneity, among Leptopilina parasitic wasp populations

Abstract

Lipid synthesis can have a major effect on survival and reproduction, yet most insect parasitoids fail to synthesize lipids. For parasitic wasps in the genus Leptopilina, however, studies have suggested that there is intraspecific variation in the ability for lipid synthesis. These studies were performed on only few populations, and a large‐scale investigation of both lipogenic ability and population genetic structure is now needed. Here, we first examined lipogenic ability of nine Leptopilina heterotoma populations collected in 2013 and found that five of nine populations synthesized lipids. The 2013 populations could not be used to determine genetic structure; hence, we obtained another 20 populations in 2016 that were tested for lipogenic ability. Thirteen of 20 populations (all Leptopilina heterotoma) were then used to determine the level of genetic differentiation (i.e., haplotype and nucleotide diversity) by sequencing neutral mitochondrial (COI) and nuclear (ITS2) markers. None of the 2016 populations synthesized lipids, and no genetic differentiation was found. Our results did reveal a nearly twofold increase in mean wasp lipid content at emergence in populations obtained in 2016 compared to 2013. We propose that our results can be explained by plasticity in lipid synthesis, where lipogenic ability is determined by environmental factors, such as developmental temperature and/or the amount of lipids carried over from the host.

Symbiont-mediated protection varies with wasp genotype in the Drosophila melanogaster–Spiroplasma interaction

“…A second explanation is the variation in the ability of the wasp to synthesise lipids, for which the Spiroplasma is thought to compete (Paredes et al 2016). Intraspecific variation in the ability to synthesise lipids has been observed in L. heterotoma (Visser et al 2018). If Lh14 is unable to synthesise lipids, this could lead to competition between Spiroplasma and the wasp for the available lipids within the host, thus leading to lower survival.…”

Overwintering of reproductively mature females of a pro‐ovigenic parasitic wasp, Leptopilina heterotoma (Hymenoptera: Figitidae)

“…; Kimura ; Visser et al . ). Its occurrence has also been reported from tropical regions (Carton et al .…”

“…In addition, adults of this species cannot synthesize storage lipids (Visser & Ellers ; Visser et al . , ). Lipid synthesis capacity might not be necessary for pro‐ovigenic adult insects, because females no longer produce eggs and males do not need so much energy for activity.…”

“…Leptopilina heterotoma (Thomson) is a Drosophila parasitoid mainly reported from temperate regions of Europe, East Asia and North America (Carton et al 1986;Novkovi c et al 2011;Kimura 2015;Visser et al 2018). Its occurrence has also been reported from tropical regions (Carton et al 1986), but the tropical populations might belong to a morphologically cryptic sibling species of L. heterotoma (Novkovi c et al 2011).…”

“…One of the remarkable reproductive characteristics of L. heterotoma is pro-ovigeny, where all or nearly all of a female's lifetime eggs are already mature at emergence (Flanders 1950;Vuarin et al 2012). In addition, adults of this species cannot synthesize storage lipids (Visser & Ellers 2008;Visser et al 2010Visser et al , 2018. Lipid synthesis capacity might not be necessary for pro-ovigenic adult insects, because females no longer produce eggs and males do not need so much energy for activity.…”