Olfactory system differentiation associated with task specialization in a polymorphic ant: Messor barbarus olfactory receptor gene annotations

Data on olfactory receptor annotations in Messor barbarus, associated with: Olfactory system differentiation associated with task specialization in a polymorphic ant Abstract: Many ant species comprise of polymorphic workers that differ in size and shape, traits associated with specialized roles within the colony. One such role is nestmate recognition, an essential task which maintains the integrity of the colony by preventing unrelated individuals from exploiting the nest. The ability to detect nestmates and non-nestmates relies on discriminating among cuticular hydrocarbon (CHC) blends, which are colony specific. This process involves a dedicated olfactory recognition system, which includes specialized antennal sensilla and specific olfactory receptor (OR) genes, both associated with a particular region in the primary olfactory processing center of the brain, the antennal lobe. Using the highly polymorphic harvester ant, Messor barbarus, we employed a multidisciplinary approach, including electron microscopy, transcriptomics, behavioral analyses and neuroanatomy, to investigate whether nestmate recognition differs amongst different worker morphs and how this might correlate with specific features of the olfactory system. We demonstrate that small workers exhibit enhanced nestmate recognition and that this ability also aligns with differences in the olfactory system, including an increased proportion of basiconic sensilla and the overexpression of certain 9-exon OR genes. Our study elucidates how social insect workers may differ at the behavioral, morphological and genetic level giving rise to task specialization within the colony.