Data from: Colony stage and not facultative policing explains pattern of worker reproduction in the Saxon wasp

Inclusive fitness theory predicts that in colonies of social Hymenoptera headed by a multiple mated queen, workers should benefit from policing eggs laid by other workers. Foster & Ratnieks (2000) provided evidence that in the vespine wasp Dolichovespula saxonica, workers police other workers' eggs only in colonies headed by a multiple mated queen, but not in those headed by a single mated one. This conclusion, however, was based on a relatively small sample size and the original study did not control for possible confounding variables such as the seasonal colony progression of the nests. Our aim, therefore, was to reinvestigate whether or not facultative worker policing occurs in D. saxonica. Remarkably, our data shows that in the studied Danish population, there was no correlation between worker-worker relatedness and the percentage of worker-derived males. In addition, we show that variability in cuticular hydrocarbon profiles among the workers did not significantly correlate with relatedness, and that workers therefore probably did not have sufficient information on queen mating frequency from the workers' cuticular hydrocarbon profiles. Hence, there was no evidence that workers facultatively policed other workers' eggs in response to queen mating frequency. Nevertheless, our data do show that the seasonal progression of the nest and the location in which the males were reared both explain the patterns of worker reproduction found. Overall, our results suggest that the earlier evidence for facultative worker policing in D. saxonica may have been due to accidental correlations with certain confounding variables, or, alternatively, that there are large interpopulation differences in the expression of worker policing.

广义适合度理论（Inclusive fitness theory）预测，在由多配蜂王统领的膜翅目社会性昆虫（social Hymenoptera）种群中，工蜂应当会对其他工蜂所产的卵实施监管。Foster与Ratnieks（2000）的研究提供了相关证据：在胡蜂科昆虫桑氏长黄胡蜂（Dolichovespula saxonica）中，工蜂仅会在由多配蜂王统领的种群内监管其他工蜂的卵，而在单配蜂王统领的种群中则无此行为。然而，该结论的样本量相对有限，且原始研究未对潜在混淆变量加以控制，例如蜂群的季节性群势发展进程。因此，本研究旨在重新探究桑氏长黄胡蜂（D. saxonica）中是否存在兼性工蜂监管（facultative worker policing）行为。值得注意的是，本次研究的丹麦种群数据显示，工蜂间的亲缘关系（worker-worker relatedness）与工蜂产雄卵占比之间并无显著相关性。此外，本研究还发现，工蜂间的表皮碳氢化合物图谱（cuticular hydrocarbon profiles）变异程度与亲缘关系并无显著关联，这意味着工蜂可能无法通过同类的表皮碳氢化合物图谱获取蜂王交配频次的足够信息。因此，并无证据表明工蜂会依据蜂王交配频次对其他工蜂所产的卵实施兼性监管。尽管如此，本研究的数据仍表明，蜂群的季节性发展进程以及雄蜂培育位点，均可解释观测到的工蜂繁殖模式。综合来看，本研究结果提示，此前关于桑氏长黄胡蜂存在兼性工蜂监管行为的证据，可能是由于与特定混淆变量间的偶然关联所致；或者，不同种群间的工蜂监管表达存在显著差异。