Effects of pollen availability and Nosema infection during the spring on division of labor and survival of worker honey bees (Hymenoptera: Apidae)

Honey bee (Apis mellifera L.) colonies in temperate climates often deplete winter pollen stores because of intense brood rearing activity in the spring. Nutritional stress can be exacerbated by a simultaneous spring peak in the incidence of the mid-gut parasite Nosema apis Zander in workers. We examined the effect of pollen supply in colonies during the spring on longevity, in-hive behavior, and foraging patterns of Nosema-infected and uninfected workers. In field colonies, pollen supplements did not offset the reduction in worker lifespan caused by inoculation with N. apis, a result that contradicts previous research that showed that increased access to pollen can improve the longevity of N, apis-inoculated workers in cage trials. This discrepancy is likely related to differences in the activity of workers in colonies versus cages; surplus nutrients in colonies were allocated to increased brood rearing activity, which presumably diverted resources away from improving the performance of infected workers in colonies. Trends were reversed when workers were transferred to a common observation hive as adults after being reared in field colonies with pollen supplements or limited pollen; pollen availability in the parental colony affected worker lifespan and the effects of N. apis status were negligible. Workers from colonies that had pollen-diet supplements lived longer, were more likely to be found in the brood area, and were more active on the comb than workers reared in colonies with less access to pollen. Pollen availability and inoculation status did not affect brood care behavior or foraging patterns.