Abstract Social insects frequently exhibit intraspecific variation in reproductive strategies, characterized by pronounced differences in the morphology, physiology and behaviour of reproductive individuals and the social organization of the colony. In many ant species, this complex variation is governed by supergenes that control multiple traits, including queen morphology and dispersal behaviour, as well as the number of queens that can coexist within a colony. Here, we investigate the genetic basis of sexual dimorphism in the ant Hypoponera opacior, which produces both winged and wingless morphs in males and queens, each associated with distinct reproductive behaviours and seasonal activity. Using whole-genome resequencing of all morphs, we tested for signatures of supergene architecture. Our analyses revealed no evidence for a supergene or other large genomic rearrangement underlying this morphological and behavioural diversity. These findings suggest that male and queen morph determination in H. opacior is not controlled by a large structural polymorphism and may instead result from phenotypic plasticity, environmentally sensitive developmental switches or polygenic factors. Our study demonstrates that complex social traits in ants can evolve and persist without supergene architectures and underscores the importance of considering alternative genetic and epigenetic mechanisms underlying reproductive polymorphisms.
Lenhart et al. (Wed,) studied this question.