Sociogenetic structure, reproductive strategies and queen replacement in the erratic ant (Tapinoma erraticum)

Abstract

AbstractAncestral eusocial insect societies were probably headed by a single and singly mated reproductive queen. However, eusocial Hymenoptera have since secondarily evolved highly diverse mating systems and social structures, which include multiple mating by queens, the coexistence of several reproductive queens within a given colony, and queen replacement over time. Here, we report pronounced plasticity in sociogenetic structure and reproductive strategies in the erratic ant, Tapinoma erraticum. Notably, colonies can be headed by one or several queens. Nestmate queens display a varying degree of genetic relatedness; they range from being unrelated to full sisters to mothers and daughters. Queens mate with one to three males. There is again variability in the degree of relatedness. The queens and their male mate(s) are sometimes related and sometimes unrelated; the same is true for the males that had mated with nestmate queens. Finally, genotypic comparisons between age-based cohorts (i.e. adult workers vs. worker larvae) indicate that new queens, both related and unrelated, appear in established colonies. We suggest that the highly plastic reproductive systems found in T. erraticum might have opened the door evolutionarily to supercoloniality and invasiveness in the genus Tapinoma.