Relatedness within colonies of three North American species of carpenter ants (Subgenus: Camponotus) and a comparison with relatedness estimates across Formicinae

Understanding a haplodiploid species' social structure and quantifying relatedness among individuals are both important when designing sampling schemes or identifying potential biases in population genetics studies. However, it is not always possible to accurately identify social structure of study species in the field, or to collect large numbers of individuals from a single colony to estimate relatedness with methods that rely on accurate estimation of allele frequencies. Here, we assessed the utility of allele-frequency-free inference of relationships in haplodiploid ant colonies, while using limited sample sizes. Using genome-wide single-nucleotide polymorphism data, we measured intracolony relatedness and kinship estimates consistent with full-sister relationships among workers in three Nearctic species: Camponotus herculeanus, C. laevissimus, and C. modoc. Notably, the allele-frequency-free inference of relationships clearly demonstrated these full-sister relationships without ambiguity; this result suggests the utility of these methods for identifying closely related individuals in population genetics studies of haplodiploid organisms. We additionally performed a literature review of relatedness estimates in the subfamily Formicinae both as a compiled resource and to place our results in context within this larger clade of ants. Our results suggestive of Camponotus colonies founded by a lone singly mated queen are consistent with previously published relatedness estimates in the genus Camponotus that have generally shown high intracolony relatedness.

Automated summary

Scientists used genome-wide single-nucleotide polymorphism data to study social structure and relatedness estimation in three Nearctic ant species. The results showed that allele-frequency-free inference can accurately determine kinship and be used in population genetics studies of haplodiploid organisms. The findings also aligned with previous research in the field.