Читать книгу Honey Bee Medicine for the Veterinary Practitioner - Группа авторов - Страница 77

Honey bees exhibit remarkable seasonal changes in their behavior and physiology in temperate climates with the changing seasons, as well as other tropical or arid climates following the cycle of flowering plants (Doke et al. 2015; Winston 1987). Winter conditions or a dearth in nectar and pollen production result in cessation of brood rearing and foraging, lifespans of the worker bee increase, and the active lifestyles of the worker and queen bees slow. Honey bees in temperate climates have stronger responses to seasonal changes compared to tropical areas (Winston 1987). Spring, summer, and fall worker bees (exhibiting an age‐based division of labor) complete most of the hive tasks – except for reproduction – sequentially with only a short lifespan of around 30–45 days, while winter honey bees – also known as diutinus bees – become generalists working to maintain a thermoregulating cluster and may live up to eight months (Winston 1987; Doke et al. 2015; Johnson 2010). Levels of vitellogenin help shape such seasonal changes in honey bee behavior and physiology and have a positive impact on lifespan; the short‐lived foraging worker bees produce less vitellogenin than nurse bees, wintering bees have the highest levels among workers, and the longest living queen bee has the highest levels of all castes (Amdam et al. 2012; Corona et al. 2007). Juvenile hormone levels (low in nurse and wintering bees) decrease in the fall and rise markedly in again in spring, suggesting that fall bees are already in their winter physiologic state, and overwintering bees return to a forager bee physiology in the spring (Doke et al. 2015; Fluri et al. 1982).