Meeting Abstract
The genetic underpinnings of social behavior are of great interest to understanding the evolution of social complexity. Genomic data for solitary and eusocial species are now available and have revealed important insights into the mechanisms of social evolution. The evolutionary path from solitary to eusocial life history likely involved intermediates, but genomic data is lacking for these species. Only by performing genomic comparisons that include the early stage social species will we truly begin to understand the genomic mechanisms underlying the transition from simple to complex societies. New data are provided on the first incipiently social bee species yet examined in depth on a genomic level. These genomic and transcriptomic data for the Australian small carpenter bee, Ceratina australensis, are used to empirically test hypotheses about the genomic basis of social transitions in bees. This species is of special interest because it is socially polymorphic with both solitary and social nests occurring in the same populations, and are an early stage social species. C. australensis provides a natural experiment to investigate the molecular changes that may underlie the transition from solitary to social life within a single species. These data demonstrate that gene regulatory changes are of primary importance relative to protein evolution in C. australensis sociality. Genes associated with social vs solitary nesting in this species show a clear signature of being deeply conserved and slow-evolving, in contrast to previous studies showing novel and faster-evolving genes associated with derived sociality in other bees. Gene family expansions and positive selection on zinc-finger transcription factors are noted in C. australensis compared to other bees. These data provide support for the idea that the earliest social transitions are driven by changes in gene regulation of deeply conserved genes.
