Genetic control of the thelytoky syndrome in the honeybee Apis melllifera capensis

The thelytoky syndrome in worker honeybees of the Cape honeybee  (Apis mellifera capensis) is a combination of traits that result in a parasitic worker phenotype including swift ovary activation, the production of queen pheromones, and thelytokous parthenogenesis (production of female offspring). These parasitic workers can invade foreign colonies, kill the resident queen and establish themselves as pseudoqueens in host colonies. Because they can parthenogenetically produce clonal female offspring, these social parasitic workers spread as clonal lineages in the population. We have identified a single locus “thelytoky” which determines this phenotype and shown in knockout experiments that ovary activation is controlled by differential splicing of the Apis homologue of gemini, a CP2 transcription factor. We here want to study how the other traits of the syndrome, namely queen pheromone synthesis and thelytokous parthenogenesis, are also controlled by this locus to confirm its relevance for the entire syndrome. We will implement siRNA knock outs of specific gemini splice products to verify the importance of this gene for the socially parasitic behaviour of honeybee workers. We will screen parasitic workers in natural populations of the Cape Honeybee to test if a 9bp deletion in the genome functions as an internal splice enhancer to cause the parasitic allelic form of the thelytoky locus.