New paper published in Proceedings of the National Academy of Sciences.

Decoding ants’ olfactory system sheds light on the evolution of social communication

Patrizia d’Ettorre, Nina Deisig Jean-Christophe Sandoz

Extract

Chemical communication is the primordial and possibly most efficient way of transmitting messages between living units (1). It has reached its apex in the “superorganisms” (2), for example in colonies of eusocial insects, such as honey bees (3). Colony survival and reproductive success rely on the chemical communication channel to maintain an advanced social organization characterized by high levels of cooperation and low levels of conflicts (1, 4, 5). Eusocial bees and ants are model organisms for understanding social chemical communication; hence, recent research has focused on the identification of chemoreceptors (6). A new study by Slone et al. (7) uses the ant Harpegnathos saltator to investigate the molecular mechanisms underlying chemoreception of socially relevant semiochemicals.

Chemoreceptors can be differentiated into olfactory receptors (ORs), gustatory receptors, and ionotropic receptors, as well as several other receptor classes (8). ORs are transmembrane proteins representing the interface between animals and their olfactory environment for detecting food sources or, in a social context, nestmates or sexual partners. They are expressed in olfactory receptor neurons (ORNs) in the insect antenna; after binding odors, information is transferred to the brain, eventually inducing behavioral responses. It has long been believed that perception of “general” odors (food and flower scent) is separated from that of “social” odors (e.g., pheromones), and that these are detected by different ORs. Recent research contradicts such strict partition: even highly specialized ORNs (sex pheromone ORNs) may respond to ordinary odors (9). In ants, colony-mate recognition relies on cuticular hydrocarbons (CHCs), which also inform about caste and reproductive status (1, 10). Being primarily a barrier against desiccation and pathogens, CHCs have been co-opted to serve as a multicomponent cue/signal (11), first in solitary species for reproduction behavior (e.g., species recognition), then in social species, where they serve at least two functions …