Regulation of pollen and nectar foraging in honeybees: changes in gustatory perception, learning and memory in bees arriving or departing from food sources

MORENO, EMILIA; ARENAS, ANDRÉS

Conferencia; Animal Behaviour Live: Annual Online Conference 2021; 2021

In honeybees, the collection of food sources (mainly protein and carbohydrates) is achieved by individuals specializing in pollen or nectar foraging. Foraging task specialization is linked to differences in bees´ sensitivity to flower’s rewards. In behavioral bioassays, the successive offering of increasing concentrations of sucrose solutions showed that nectar foragers are less sensitive to sucrose than pollen foragers. This results suggest that a low gustatory sensitivity could enable nectar foragers to prefer visiting concentrated sugar sources. So far, differences in gustatory perception have been observed between nectar and pollen foragers returning to the hive, but have not yet been studied in bees at the beginning of their foraging visit (i.e. highly motivated to forage). By means of the proboscis extension reflex (PER), an innate response elicited when sugar solution contacts the antennae, we measured the gustatory sensitivity of foragers (n=192) arriving or departing from pollen or sugar feeders. In addition, we olfactory conditioned pollen foragers (n=247) to study differences in acquisition and retention of odour – sucrose associations vs. odour – sucrose + pollen associations, at the beginning and at the end of the visits. Interestingly stadistical analysis showed that, at arrivals, pollen foragers were less responsive than nectar foragers (p=0.019; z ratio=3.93) and performed better with the dual (sucrose + pollen) reinforcement than with sucrose alone (p inferior to 0.0001; z ratio= -4.884). As it was expected for departures, pollen foragers showed higher gustatory sensitivity than nectar foragers (p inferior to 0.0001; z ratio= 8.610) and performed similarly during conditioning with or without pollen reinforcement (p=0.96; z ratio= -0.247). Our results are consistent with the fact that low sucrose responsiveness at the beginning of the foraging visit would prevent pollen foragers from being attracted to nectar sources while enable them to learn source-related cues reinforced with pollen.