Genetic determinants of honey bee foraging behaviour

The amount of pollen stored in honey bee, Apis mellifera, colonies is a selectable trait. Five generations of two-way selection resulted in high and low strains that differed more than six-fold in quantities of stored pollen. Comparisons with hybrid crosses suggested that colony-level, high pollen-hoarding behaviour is inherited as a recessive trait. Colony levels of stored honey, however, showed an over-dominant pattern, with hybrid colonies storing significantly more honey than either of the selected strains. Controlled studies of individual foraging behaviour revealed the same patterns of inheritance at the individual level: high-strain workers specialized on pollen foraging, low-strain workers on nectar, and hybrid workers demonstrated a significantly greater nectar-collecting bias than workers of the low strain. Genomic mapping studies of colony-level pollen hoarding and individual foraging behaviour have revealed two genomic regions of the honey bee that contain major quantitative trait loci that explain a large portion of the observed variance in pollen hoarding and foraging behaviour of the two strains. The effects of major genes on withinand between-colony variation in individual foraging behaviour are discussed in the context of conducting and interpreting empirical tests of foraging theory.