Effects of Nutritional Stress on Aspects of Worker Performance in the Honey Bee (Apis mellifera)

Juvenile malnourishment affects learning and task performance in many species, and is well documented in mammals, but poorly studied in invertebrates. We examined the effect of nutritional stress during larval development on the longevity and task performance of honey bee (Apis mellifera) adults. Nutritional stress occurs naturally in honey bee colonies when pollen, which provides honey bees with essential nutrients, is in short supply. Workers can compensate for food shortages by distributing nutrients among fewer larvae, cannibalizing brood, or ceasing brood rearing altogether. Despite measures to ensure larvae are adequately nourished, observations of undersized adults suggest that worker quality suffers during pollen shortages. It is not known how pollen deprivation during larval development affects the performance of honey bee workers as adults. We compared foraging behavior between cohorts of workers that were reared under conditions of either pollen deprivation or abundance. A natural spring pollen dearth was simulated by placing frames of honey comb with adult workers, young larvae, and very little stored pollen in a cool incubator (5 ̊C). After eclosion, cohorts of nutritionally stressed day-old adult workers were individually weighed, tagged, and introduced into an observation hive. Matching cohorts of day-old adult workers from the same colonies, but reared under free-flying conditions with access to pollen, were introduced into observation hives as controls. Nutritionally stressed workers were on average 33% lighter than control workers. Longevity, onset and duration of foraging, and waggle-dance activity of tagged workers were monitored to determine the effect of nutritional stress during larval development on the performance of workers as adults. Nutritional stress had a clear impact on worker weight and function, providing insight into the relationship between nutritional stress and performance in a model invertebrate and an economically important pollinator.