Data from: A limit on the extent to which increased egg size can compensate for a poor postnatal environment revealed experimentally in the burying beetle, Nicrophorus vespilloides

It is often assumed that there is a positive relationship between egg size and offspring fitness. However, recent studies have suggested that egg size has a greater effect on offspring fitness in low-quality environments than in high-quality environments. Such observations suggest that mothers may compensate for poor posthatching environments by increasing egg size. In this paper we test whether there is a limit on the extent to which increased egg size can compensate for the removal of posthatching parental care in the burying beetle, Nicrophorus vespilloides. Previous experiments with N. vespilloides suggest that an increased egg size can compensate for a relatively poor environment after hatching. Here, we phenotypically engineered female N. vespilloides to produce large or small eggs by varying the amount of time they were allowed to feed on the carcass as larvae. We then tested whether differences between these groups in egg size translated into differences in larval performance in a harsh postnatal environment that excluded parental care. We found that females engineered to produce large eggs did not have higher breeding success, and nor did they produce larger larvae than females engineered to produce small eggs. These results suggest that there is a limit on the extent to which increased maternal investment in egg size can compensate for a poor posthatching environment. We discuss the implication of our results for a recent study showing that experimental N. vespilloides populations can adapt rapidly to the absence of posthatching parental care.学界普遍认为卵大小与子代适合度呈正相关关系。然而近期研究表明，在低质量环境中，卵大小对子代适合度的影响强度显著高于高质量环境。此类观察结果提示，母体或可通过增大卵体积，弥补孵化后不良环境带来的不利影响。本研究以埋葬甲（Nicrophorus vespilloides）为实验对象，旨在验证：增大卵体积对移除孵化后亲代抚育行为的补偿效应是否存在上限。此前针对N. vespilloides的实验研究表明，增大卵体积可补偿孵化后相对恶劣的环境条件。本研究通过调整雌性埋葬甲幼虫期取食腐尸的时长，对其进行表型工程化处理，使其产出大小分化的卵；随后在排除亲代抚育的严苛产后环境中，检验两组个体的卵大小差异是否会转化为幼虫表现的差异。研究结果显示，经处理产出大卵的雌性个体，其繁殖成功率并未更高，所产幼虫体型也并未大于经处理产出小卵的雌性个体所产幼虫。上述结果表明，母体通过增大卵体积所增加的投入，对孵化后不良环境的补偿效应存在上限。本研究最后讨论了本结果对近期一项研究的启示：该研究证实，实验饲养的N. vespilloides种群可快速适应无孵化后亲代抚育的生存环境。