Antennal proteomics of allogroomers and same age range non-grooming bees

Allogrooming is a behaviour in which a worker uses its mouth parts to remove debris from the body of other colony members. This behaviour, observed in several species of eusocial insects, play a role in defence against parasites and pathogens. In honeybees, allogrooming represents an important resistance mechanism that seems to limit ectoparasites load, especially mites, within colonies and its expression depends on genetic and environmental factors. The degree of specialization of individuals performing this task is still unclear and behavioural and physiological correlates of allogroomers are largely unknown. It would be advantageous for allogroomers to be able to detect nestmates needing to be groomed. Since many stressors, including pathogens and parasites, change the odour of workers in A. mellifera, an enhanced perception of such chemical cues could contribute to a possibly specialized phenotype of allogroomers. Indeed, antennae play a key role in the expression of hygienic behaviours and proteomic investigation also showed that in the honeybee individuals performing different tasks differ for antennal profile of soluble olfactory proteins, which play a crucial role in the first steps of odour recognition. We thus investigated the expression of olfactory proteins in the antennae, predicting that if allogroomers have any degree of chemosensory specialization, this would reflect in a different antennal proteomic profile.