Olfactory experiences within the beehives – long lasting implications of precocious learning.

FARINA WM

Washington DC

Workshop; Janelia Farm Conference: Learning and Memory: A Synthesis of Flies and Honeybees; 2011

HHMI

Cognitive experiences during the early stages of life play an important role in shaping the future behavior in mammals but also in insects, in which precocious learning events can modify behaviors at a long-term scale. Olfactory conditioning during the first days of the adult lifespan affects long-lasting retention and also memorizing of new learning events in honeybees. Odor-rewarded experiences occurred during young adulthood is also manifested in an increase of the general odor-induced activity in the honeybee brain’s primary olfactory center, the antennal lobe (AL). Qualitative olfactory representations appear to be shifted in the neural space in precocious learners. Interestingly, the brains´ shape of bees with early odor-rewarded experiences is also modified. These changes were specific for the identity of the learned odor. Thus, comparison between neuro-anatomical measurements and in vivo optical imaging of calcium activity revealed that those glomeruli that increased most in size after early stimulation appeared as new recruited active glomeruli in odor-evoked patterns of activity. Particularly in honeybees this plasticity is highly relevant due to the consequences at a social scale. Honeybees can learn food odors inside the nest during food sharing and use this information during flower choice, dance choice or choice of a trophallactic partner. These in-hive learning events can last for up to 10-11 days and could be recalled once worker bees initiate foraging duties. This has been tested recently and it has been found that olfactory information acquired by young hive bees can be retrieved when early experienced bees performed foraging-related tasks later in life. Bees with these precocious memories interacted more intensively with foragers which brought back food scented with the same floral odor circulated inside the nest 8 days before. These bees also followed more dancers scented with the early circulated food odor and even were recruited in a higher proportion toward the feeder containing this odor. Then, the role of precocious olfactory learning is an important matter in the honeybee social life showing long lasting implications at the neuro- and socio-biological levels.