Data from: The influence of social structure on brood survival and development in a socially polymorphic ant: insights from a cross-fostering experiment

Animal societies vary in the number of breeders per group, which affects many socially and ecologically relevant traits. In several social insect species, including our study species Formica selysi, the presence of either one or multiple reproducing females per colony is generally associated with differences in a suite of traits such as the body size of individuals. However, the proximate mechanisms and ontogenetic processes generating such differences between social structures are poorly known. Here, we cross-fostered eggs originating from single-queen (=monogynous) or multiple-queen (=polygynous) colonies into experimental groups of workers from each social structure to investigate whether differences in offspring survival, development time and body size are shaped by the genotype and/or pre-foster maternal effects present in the eggs, or by the social origin of the rearing workers. Eggs produced by polygynous queens were more likely to survive to adulthood than eggs from monogynous queens, regardless of the social origin of the rearing workers. However, brood from monogynous queens grew faster than brood from polygynous queens. The social origin of the rearing workers influenced the probability of brood survival, with workers from monogynous colonies rearing more brood to adulthood than workers from polygynous colonies. The social origin of eggs or rearing workers had no significant effect on the head size of the resulting workers in our standardized laboratory conditions. Overall, the social backgrounds of the parents and of the rearing workers appear to shape distinct survival and developmental traits of ant brood.

动物社群的群内繁殖者数目存在变异，该变异会对诸多社会关联与生态相关的性状产生影响。在多种社会性昆虫类群中，包括本研究的模式物种塞氏林蚁（Formica selysi），每个蚁群仅存在1只繁殖雌蚁或存在多只繁殖雌蚁的社会结构，通常会伴随个体体型等一系列性状的差异。然而，导致不同社会结构间产生此类差异的近因机制与个体发育过程，目前仍不甚明晰。本研究中，我们将来自单后制（monogynous）或多后制（polygynous）蚁群的卵，分别转移至对应两种社会结构的工蚁实验组中进行抚育，以此探究后代存活率、发育时长与体型的差异，究竟是由卵内携带的基因型及/或寄养前母体效应所决定，还是由抚育工蚁的社会背景所塑造。无论抚育工蚁的社会背景如何，多后制蚁后所产的卵，其发育至成虫的存活率均高于单后制蚁后所产的卵。但单后制蚁后所产的子代幼体，其发育速率快于多后制蚁后的子代幼体。抚育工蚁的社会背景同样会影响子代幼体的存活概率：单后制蚁群的工蚁抚育出的成虫子代数量，多于多后制蚁群的工蚁。在本研究的标准化实验室条件下，卵的社会背景或抚育工蚁的社会背景，对子代工蚁的头部大小均无显著影响。综上，亲代与抚育工蚁的社会背景，似乎会分别塑造蚁类子代幼体不同的存活与发育性状。