cGMP-dependent protein kinase, behavioral plasticity, and foraging in honey bees and fruit flies

Here I describe a study of comparative behavioral genetics of a complex behavioral phenotype that is affected by a gene encoding a cGMP-dependent protein kinase (PKG, foraging). I accomplish this by using a traditional genetic model—the fruit fly, Drosophila melanogaster , and a traditional behavioral model—the honey bee, Apis mellifera. Variation in the for gene results in naturally occurring behavioral polymorphism. Two fly alleles have been identified; rover flies show longer foraging trails and higher PKG activity than sitter flies. In a series of behavioral, molecular, biochemical, and neurophysiological experiments I show that temporal changes in foraging (for) activity in both flies and bees modulate plasticity of foraging behavior. In bees, an increase in for activity is involved in the transition from in-hive nursing behavior to outside foraging behavior. I also show that this for-dependent transition is mediated, at least in part, by modulating the response of bees to light (positive phototaxis). In flies I show that individual variation in foraging intensity is mediated by both natural polymorphism in the for locus as well as environmentally-dependent temporal and spatial changes in for expression. Specifically, an animal with a rover genotype will show a more sitter-like behavior under food deprivation conditions. for encodes a variety of transcripts due to alternative splicing, and I also show that these environmentally-dependent changes in for expression may be regulated in a transcript- and tissue-specific manner via post-transcriptional mechanisms. Together, these results indicate that the foraging gene plays a conserved key role in modulating complex behavioral phenotype.