Early olfactory but not gustatory processing is affected by the selection of cognitive phenotypes in honey bee genetic lines

Associative learning enables animals to predict rewards or punishments by their associations with previously neutral stimuli, while non-associative learning occurs without reinforcement. The latter includes a phenomenon, known as latent inhibition (LI), where animals learn to ignore an inconsequential familiar stimulus. Individual honey bees display differences in expression of LI, and these differences are heritable. We examined the behavioral and neuronal responses between honey bee genetic lines exhibiting variation in LI to determine how variation in LI phenotypes are shaped. We observed that high LI lines learned a familiar odor slowly, but low LI individuals readily learned to respond to that odor. By measuring their gustatory response to sucrose, we determined that perception of sucrose reward was similar between both LI lines, thereby not contributing to the phenotypical LI variation. We then used extracellular electrophysiology to determine differences in neural responses of the antennal lobe (AL) to familiar and novel odor between the LI lines. Low LI bees responded significantly more strongly to odors than the high LI bees after the familiarization process, but the differences were not influenced by whether the odors were novel or familiar. This work suggests that non-associative plasticity is not limited in the AL.