Meeting Abstract

47.2  Jan. 6  Flight induced oxidative stress and Hsp70 expression in aging honey bees, Apis mellifera WILLIAMS, J.B.*; ROBERTS, S.P.; ELEKONICH, M.M.; Univ. of Nevada, Las Vegas; Univ. of Nevada, Las Vegas; Univ. of Nevada, Las Vegas jason.williams@unlv.edu

As honey bees age they switch from in-colony tasks, such as nursing, to foraging for nectar and pollen outside the colony. Nurses rarely fly, have a relatively low metabolic rate, and experience a homogeneous colony environment. By contrast, foragers have the highest measured mass specific metabolic rates and produce thoracic temperatures that are 6-7�C higher than heads during frequent foraging trips. Consequently, foragers have a six-fold higher concentration of the stress protein Hsp70 in their thoraces than their heads, as well as two-fold and six-fold higher Hsp70 levels than nurse thoraces and heads. Interestingly, temperature does not induce Hsp70 expression in forager thoraces at typical flight temperatures or even after exposure to 50�C for 1h. In this ongoing study, we used the metabolic differences between nurse and forager honey bees to test the hypothesis that oxidative stress, rather than temperature stress, induces Hsp70 expression in forager thoraces. We measured carbonyl content (a measure of protein oxidative damage), total antioxidant activity, and expression of Hsp70 and the antioxidant enzymes, superoxide dismutase and catalase, in thoraces and heads of 9 to11 day-old foragers and nurses collected as foraging activity begins (8-10am) or at end of the foraging day (3-4pm). To determine the effect of a single foraging flight on tissue oxidative damage and Hsp70 expression, we measured the above parameters on thoraces and heads of foragers that were collected while leaving or returning from flights at each collection period. To assess the effect of age on accrued oxidative damage and Hsp70 expression we repeated the above experiments on bees aged 30 to 32 days.