Honey bees dance faster for pollen that complements colony essential fatty acid deficiency

Honey bee colonies require adequate pollen for maintenance and growth. Pollens vary in nutritional value, and a balanced diet is achieved by mixing pollens with complementary essential nutrients. We tested subjective evaluation of pollens by foragers in colonies deprived of one of two essential fatty acids (eFAs), alpha-linolenic acid (omega-3) or linoleic acid (omega-6). We used four pollens, two rich in omega-3 and two rich in omega-6. A colony in an observation hive was allowed to forage for 2-5 days on a single pollen source. The following day, we repeatedly presented one of three pollens: the same pollen that the bees had been collecting the previous days, a novel pollen that was similarly deficient in omega-3 or omega-6, and a novel pollen that complemented their eFA deficiency. We measured the rate of waggle dances, which reflects on the strength of recruitment effort, of foragers returning to the observation hive from each of the pollens. Dance rates did not differ between the four pollens, but they were the highest to the complementary pollen and the lowest to the same pollen. Furthermore, this effect was greater for pollen combinations with greater eFA disparity between the same and the complementary pollens. Our findings support the ability of bees to balance colony eFA intake. Conditioning of the proboscis extension response (PER) tests showed that pollen foragers discriminated well between the four pollen odors, but the mechanisms by which bees assess pollen eFA composition remain to be elucidated. Differential dancing would recruit foragers to pollens that balance colony nutritional needs.