The Transcriptomic Basis of Oviposition Behaviour in the Parasitoid Wasp Nasonia vitripennis

Abstract

Linking behavioural phenotypes to their underlying genotypes is crucial for uncovering the mechanisms that underpin behaviour and for understanding the origins and maintenance of genetic variation in behaviour. Recently, interest has begun to focus on the transcriptome as a route for identifying genes and gene pathways associated with behaviour. For many behavioural traits studied at the phenotypic level, we have little or no idea of where to start searching for “candidate” genes: the transcriptome provides such a starting point. Here we consider transcriptomic changes associated with oviposition in the parasitoid wasp Nasonia vitripennis. Oviposition is a key behaviour for parasitoids, as females are faced with a variety of decisions that will impact offspring fitness. These include choosing between hosts of differing quality, as well as making decisions regarding clutch size and offspring sex ratio. We compared the whole-body transcriptomes of resting or ovipositing female Nasonia using a “DeepSAGE” gene expression approach on the Illumina sequencing platform. We identified 332 tags that were significantly differentially expressed between the two treatments, with 77% of the changes associated with greater expression in resting females. Oviposition therefore appears to focus gene expression away from a number of physiological processes, with gene ontologies suggesting that aspects of metabolism may be down-regulated during egg-laying. Nine of the most abundant differentially expressed tags showed greater expression in ovipositing females though, including the genes purity-of-essence (associated with behavioural phenotypes in Drosophila) and glucose dehydrogenase (GLD). The GLD protein has been implicated in sperm storage and release in Drosophila and so provides a possible candidate for the control of sex allocation by female Nasonia during oviposition. Oviposition in Nasonia therefore clearly modifies the transcriptome, providing a starting point for the genetic dissection of oviposition.

Analysis of antennal transcriptome and odorant binding protein expression profiles of the recently identified parasitoid wasp, Sclerodermus sp.

“…2, the distribution of unigenes annotated as molecular function showed that the genes expressed in the antennae were primarily related to binding activity (6545 unigenes, 46.19%), whereas 1236 (8.72%) of the unigenes were involved in transporter activity. Similar trends in GO annotation were also observed in the transcriptomic analyses of C. vestalis and N. vitripennis (Nishimura et al, 2012;Pannebakker et al, 2013).…”

Life‐history traits of the Whiting polyploid line of the parasitoid Nasonia vitripennis

“…Female Nasonia are synovigenic, meaning that they emerge from their host with a partial complement of mature eggs and can reproduce right away, but will continue to produce eggs as long as they consume enough protein (Pannebakker et al, 2013). Therefore, the WPL gives first insight on the parasitization ability of polyploid parasitoid females.…”

DNA Methylation and Sex Allocation in the Parasitoid WaspNasonia vitripennis

“…However, females produce less-biased, or even male-biased, sex ratios, depending on the number of other females (foundresses) ovipositing together on a host and the relative clutch sizes produced by those females (Hamilton 1967;Werren 1980;). While we have a detailed understanding of the information used by female Nasonia during sex allocation (e.g., Werren 1980Werren , 1983King et al 1995;Shuker and West 2004;Shuker et al 2005Shuker et al , 2006aBurton-Chellew et al 2008), we have only a rudimentary understanding of the genetic basis of sex allocation (Pannebakker et al 2008(Pannebakker et al , 2011(Pannebakker et al , 2013.…”

“…First, the sex allocation machinery, from the perception of LMC cues (e.g., Shuker and West 2004) to the control of fertilization, could be independent of any influence of DNA methylation. We have recently shown that facultative sex allocation in N. vitripennis is not associated with changes in gene expression, even though oviposition itself is (Pannebakker et al 2013 A, The optimal sex ratios under local mate competition for maternally inherited alleles (blue curve) and paternally inherited alleles (red curve) for a haplodiploid with female control of sex allocation (the black curve is the local mate competition prediction with no genomic conflict; equations given in Wild and West 2009). B, Females treated with 5-aza-2 0 -deoxycytidine (red bars) produce slightly less female-biased sex ratios than controls (blue bars).…”