Data from: Paternal signature in kin recognition cues of a social insect: concealed in juveniles, revealed in adults

Kin recognition is a key mechanism to direct social behaviors towards related individuals or avoid inbreeding depression. In insects, recognition is generally mediated by cuticular hydrocarbon compounds (CHC), which are partly inherited from parents. However in social insects, potential nepotistic conflicts between group members from different patrilines are predicted to select against the expression of patriline-specific signatures in CHC profiles. Whereas this key prediction in the evolution of insect signaling received empirical support in eusocial insects, it remains unclear whether it can be generalized beyond eusociality to less-derived forms of social life. Here, we addressed this issue by manipulating the number of fathers siring clutches tended by females of the European earwig, Forficula auricularia, analyzing the CHC profiles of the resulting juvenile and adult offspring, and using discriminant analysis to estimate the information content of CHC with respect to the maternal and paternal origin of individuals. As predicted if paternally inherited cues are concealed during family life, increases in mating number had no effect on information content of CHC profiles among earwig juveniles, but significantly decreased the one among the CHC profiles among adult offspring. We suggest that age-dependent expression of patriline-specific cues evolved to limit the risks of nepotism as family-living juveniles and favor sib-mating avoidance as group-living adults. These results highlight the role of parental care and social life in the evolution of chemical communication and recognition cues.

亲缘识别（Kin recognition）是指导社会行为指向亲缘个体或规避近交衰退的核心机制。在昆虫中，识别过程通常由表皮碳氢化合物（Cuticular Hydrocarbon Compounds, CHC）介导，这类化合物部分遗传自亲本。然而在社会性昆虫中，来自不同父系谱系的群体成员间潜在的亲缘偏袒冲突，被预测会对CHC谱中父系谱系特异性特征的表达产生负选择压力。尽管昆虫信号演化中的这一关键预测已在真社会性昆虫中获得实证支持，但目前仍不清楚该结论能否推广至真社会性之外的较低级社会生活形式。本研究以欧洲球螋（Forficula auricularia）的雌性抚育的卵簇为实验对象，通过操控父本数量，分析子代幼体与成体的CHC谱，并利用判别分析评估CHC携带的个体母系与父系起源信息含量。正如“父本遗传信号在家庭群居阶段被隐藏”的预测所示，交配次数的增加对球螋幼体CHC谱的信息含量无显著影响，但显著降低了成体CHC谱的信息含量。我们推测，父系谱系特异性特征的年龄依赖性表达，会在家庭群居的幼体阶段限制亲缘偏袒风险，而在群体群居的成体阶段促进同胞交配规避。本研究结果凸显了亲代抚育与社会生活在化学通讯及识别信号演化中的重要作用。