Division of labour in the black garden ant (Lasius niger) leads to three distinct proteomes

Abstract

Task specialization in social insects leads to striking intra-specific differences in behaviour, morphology, physiology and longevity, but the underlying mechanisms remain not yet fully understood. Adult colonies of black garden ants (Lasius niger) have a single queen fertilized by one or a small number of males. The inter-individual genetic variability is thus relatively low, making it easier to focus on the individual molecular differences linked to the division of labour. Mass spectrometry-based proteomics enabled us to highlight which biological functions create the difference between queens, foragers and nest-workers. The proteome of each caste reflected nicely their social role: e.g., reproduction for queens, pesticide resistance for foragers – that are the most exposed to environmental risk factors – and, interestingly, digestion for nest-workers, thus highlighting proteomic profiles differences even among workers. Furthermore, our exploratory approach suggests energy trade-off mechanisms – in connection with the theory of social immunity – that might explain the difference in longevity between queens and workers. This study brings evidence that proteomics is able to highlight the subtle mechanisms of molecular regulation induced by social organization.