Synergies between division of labor and gut microbiomes of social insects

Export Date: 10 March 2020 Correspondence Address: Sinotte, V.M.; Section for Ecology and Evolution, Department of Biology, University of CopenhagenDenmark; email: veronica.sinotte@bio.ku.dk Funding text 1: We thank Jacobus J. Boomsma and E. Allen Herre for fruitful discussion and Kasun H. Bodawatta for comments to an earlier version of the manuscript. Funding. This work was supported by a Ph.D. stipend from the Department of Biology, University of Copenhagen to VS, a Ph.D. studentship from the Natural Environment Research Council (NERC) to BT, HFSP-RGP0060/2018 to MV-C, and an ERC Consolidator grant (771349) to MP. ; International audience ; Social insects maximize resource acquisition and allocation through division of labor and associations with microbial symbionts. Colonies divide labor among castes and subcastes, where the plasticity of caste roles decreases in clades with higher social grades. Recent studies indicate that specific castes may also foster distinct gut microbiomes, suggesting synergies between division of labor and symbiosis. The social organization of a colony potentially partitions evolutionary persistent microbial partners to optimize symbioses and complement division of labor. However, research in this area has received limited attention. To elucidate if a structured microbiota is adaptive, we present three testable predictions to address consistent community structure, beneficial functions, and selection for microbiota that support caste roles. First, we posit that social insect groups spanning lower to higher social grades exhibit increasingly distinct caste microbiomes, suggesting that structured microbiomes may have evolved in parallel to social complexity. Second, we contend that the development of these microbiomes during colony maturation may clarify the extent to which they support division of labor. Third, we predict that mature social insect colonies with the most extreme division of labor demonstrate the strongest distinctions between caste microbiomes, carrying the greatest ...