Distribution of antennal olfactory and non-olfactory sensilla in different species of bees

Several species of social bees exhibit population-level lateralization in learning odors and recalling olfactory memories. Honeybees Apis mellifera and Australian social stingless bees Trigona carbonaria and Austroplebeia australis are better able to recall short- and long-term memory through the right and left antenna respectively, whereas non-social mason bees Osmia rufa are not lateralized in this way. In honeybees, this asymmetry may be partially explained by a morphological asymmetry at the peripheral level—the right antenna has 5% more olfactory sensilla than the left antenna. Here we looked at the possible correlation between the number of the antennal sensilla and the behavioral asymmetry in the recall of olfactory memories in A. australis and O. rufa. We found no population-level asymmetry in the antennal sensilla distribution in either species examined. This suggests that the behavioral asymmetry present in the stingless bees A. australis may not depend on lateral differences in antennal receptor numbers.