Data from: Cues of maternal condition influence offspring selfishness

The evolution of parent-offspring communication was mostly studied from the perspective of parents responding to begging signals conveying information about offspring condition. Parents should respond to begging because of the differential fitness returns obtained from their investment in offspring that differ in condition. For analogous reasons, offspring should adjust their behavior to cues/signals of parental condition: parents that differ in condition pay differential costs of care and, hence, should provide different amounts of food. In this study, we experimentally tested in the European earwig (Forficula auricularia) if cues of maternal condition affect offspring behavior in terms of sibling cannibalism. We experimentally manipulated female condition by providing them with different amounts of food, kept nymph condition constant, allowed for nymph exposure to chemical maternal cues over extended time, quantified nymph survival (deaths being due to cannibalism) and extracted and analyzed the females’ cuticular hydrocarbons (CHC). Nymph survival was significantly affected by chemical cues of maternal condition, and this effect depended on the timing of breeding. Cues of poor maternal condition enhanced nymph survival in early broods, but reduced nymph survival in late broods, and vice versa for cues of good condition. Furthermore, female condition affected the quantitative composition of their CHC profile which in turn predicted nymph survival patterns. Thus, earwig offspring are sensitive to chemical cues of maternal condition and nymphs from early and late broods show opposite reactions to the same chemical cues. Together with former evidence on maternal sensitivities to condition-dependent nymph chemical cues, our study shows context-dependent reciprocal information exchange about condition between earwig mothers and their offspring, potentially mediated by cuticular hydrocarbons.亲子交流的演化研究大多以父母回应乞食信号的视角开展，这类信号可传递子代的身体状况信息。父母之所以会对乞食行为作出回应，是因为针对不同状况子代的抚育投资所能带来的适合度回报存在差异。基于相似的逻辑，子代也应当调整自身行为，以响应亲代身体状况的线索或信号：不同状况的亲代在抚育后代时需付出差异化的抚育成本，因此会提供不同额度的食物。本研究以欧洲蠼螋（Forficula auricularia）为实验对象，通过实验探究母方身体状况的线索是否会通过同类相食行为影响子代行为。我们通过控制雌虫的食物供给量人为调控其身体状况，同时保持若虫的身体状况恒定；让若虫在较长时长内接触雌虫的化学线索；量化若虫的存活率（死亡原因均为同类相食）；并提取并分析了雌虫的表皮碳氢化合物（cuticular hydrocarbons, CHC）。研究结果显示，若虫存活率会显著受到母方身体状况化学线索的影响，且该效应取决于繁殖时机：母方状况较差的化学线索可提升早期繁殖组的若虫存活率，却会降低晚期繁殖组的若虫存活率；母方状况较好的化学线索则呈现出完全相反的效果。此外，雌虫的身体状况会影响其表皮碳氢化合物谱的定量组成，而该组成恰好能够预测若虫的存活率变化模式。综上，蠼螋子代对母方身体状况的化学线索具有敏感性，且早期与晚期繁殖组的若虫对同类化学线索会表现出截然相反的反应。结合此前关于母方对依赖于子代状况的化学线索敏感性的研究证据，本研究揭示了蠼螋亲代与子代之间存在依赖于情境的双向条件信息交流，且该交流可能由表皮碳氢化合物所介导。