Data from: DNA methylation and sex allocation in the parasitoid wasp Nasonia vitripennis

The role of epigenetics in the control and evolution of behavior is being increasingly recognized. Here we test whether DNA methylation influences patterns of adaptive sex allocation in the parasitoid wasp Nasonia vitripennis. Female N. vitripennis allocate offspring sex broadly in line with local mate competition (LMC) theory. However, recent theory has highlighted how genomic conflict may influence sex allocation under LMC, conflict that requires parent-of-origin information to be retained by alleles through some form of epigenetic signal. We manipulated whole-genome DNA methylation in N. vitripennis females using the hypomethylating agent 5-aza-2′-deoxycytidine. Across two replicated experiments, we show that disruption of DNA methylation does not ablate the facultative sex allocation response of females, as sex ratios still vary with cofoundress number as in the classical theory. However, sex ratios are generally shifted upward when DNA methylation is disrupted. Our data are consistent with predictions from genomic conflict over sex allocation theory and suggest that sex ratios may be closer to the optimum for maternally inherited alleles.表观遗传学（epigenetics）在行为调控与行为演化中的作用正日益受到学界重视。本研究旨在探究DNA甲基化（DNA methylation）是否会影响寄生蜂丽蝇蛹集金小蜂（Nasonia vitripennis）的适应性性分配模式。雌性丽蝇蛹集金小蜂的子代性比分配大体符合局部交配竞争（local mate competition, LMC）理论。然而，近期理论研究指出，在LMC情境下基因组冲突（genomic conflict）可能会对性分配产生影响，这类冲突需要等位基因（alleles）通过某种表观遗传信号保留亲本来源信息。本研究使用低甲基化试剂5-氮杂-2'-脱氧胞苷（5-aza-2′-deoxycytidine）对雌性丽蝇蛹集金小蜂的全基因组DNA甲基化水平进行干扰。在两项重复实验中，我们发现DNA甲基化的破坏并未消除雌性的兼性性分配响应：其性比仍会如同经典理论所预测的那样，随联合产卵雌蜂数量的变化而改变。不过，当DNA甲基化被干扰时，性比整体呈上升趋势。本研究数据与性分配基因组冲突理论的预测结果一致，表明此时的性比可能更接近母本遗传等位基因的最优值。