Selection on worker honeybee responses to queen pheromone (Apis mellifera L.)

Disruptive selection for responsiveness to queen mandibular gland pheromone (QMP) in the retinue bioassay resulted in the production of high and low Q MP responding strains of honeybees (Apis mellifera L.), Strains differed si gnificantly in their retinue response to QMP after one generation of select ion. By the third generation the high strain was on average at least nine t imes more responsive than the low strain, The strains showed seasonal pheno typic plasticity such that both strains were more responsive to the pheromo ne in the spring than in the fall. Directional selection for low seasonal v ariation indicated that phenotypic plasticity was an additional genetic com ponent to retinue response to QMP. Selection for high and low retinue respo nsiveness to QMP was not an artifact of the synthetic blend because both st rains were equally responsive or non-responsive to whole mandibular gland e xtracts compared with QMP. The use of these strains clearly pointed to an e xtra-mandibular source of retinue pheromones (Pankiw et al. 1995; Slessor e t al. 1998; Keeling et al. 1999).