PKA and PKC content in the honey bee central brain differs in genotypic strains with distinct foraging behavior.

Selection of honey bees for pollen storage resulted in high and low pollen-hoarding strains differing in foraging behavior traits including resource choice and quality, load size, sucrose responsiveness, age of foraging initiation, and learning performance. To determine how these genotypic differences correlate with changes at the level of proteins involved in neuronal function, we measured the content of protein kinase A, protein kinase C, and synapsin in the brains of high- and low-strain bees. In the central brain protein kinase A and protein kinase C levels were greater in high-strain bees and increased from emergence to 5 days in both strains. By 15 days, high-strain bees retained significantly higher levels of protein kinase C than low-strain bees, but overall protein kinase C content decreased in both strains. Synapsin levels increased from emergence to 5 days but did not differ between the two strains. In contrast to the protein kinase A content in the central brain, the basal protein kinase A activity did not differ between the strains or between the two age groups. This provides first evidence that the two genetic strains of honey bees show characteristic differences in the regulation of protein expression that may contribute to the behavioral differences between them.