ELEKONICH, M. M.; University of Nevada, Las Vegas: Heat Shock Protein Expression in a Heterothermic Insect Relative to Age, Behavior and Tissue Type

Adult honey bees undergo a process of adult behavioral development, spending their first 2-3 weeks working inside the constant environment of the hive which the bees maintain at 33-35°C and 70-80 percent relative humidity. At about 3 weeks of age workers leave the hive as foragers who gather pollen and nectar and are exposed to a more variable environment. The transition from the constant environment of the hive to the more variable environment experienced by foragers offers a unique model system to study social influences on the metabolic, physiological and genetic underpinnings of major transitions in behavior and life history. Heat shock proteins (Hsps) or stress proteins are expressed in response to heat, and various environmental stressors. Hsps function as molecular chaperones to bind damaged proteins and refold them or tag them for degradation. We investigated both the heat shock response and constitutive heat shock protein (Hsp70/Hsc 70) expression in the brains and thoraces of individuals of different ages, behavioral groups and following exposure to various potential stressors. Following 4 hours of heat stress at 42°C individual 9d old bees show increased Hsp70 expression mRNA expression with no induction at hive temperature (33°C). Hsp 70 and Hsc70-4 mRNA is differentially expressed in the brains of bees from different behavioral groups and exposed to different potential stressors with foragers and newly emerged bees having higher Hsp/Hsc70 expression than hive bees or restrained bees. Constituitive expression of Hsp70 protein is higher in the thoraces of foragers than of hive bees, but there is no difference in levels of Hsp 70 protein in the brain. Differences in protein expression in foragers and hive bees likely reflects foragers� specialization for flight.