Thelytoky in Cape honeybees (Apis mellifera capensis) is controlled by a single recessive locus

Abstract

Worker reproduction in Apis mellifera typically leads to haploid males produced via arrhenotokous parthenogenesis. An exception are laying workers of the South African Cape honeybee Apis mellifera capensis. Due to an abnormal spindle rotation during meiosis A. m. capensis workers are able to produce female progeny via thelytokous parthenogenesis. This trait has been suggested to be genetically controlled by a recessive allele at the thelytoky locus (th), but this conclusion was recently challenged by Chapman et al. (2015). To clarify the mode of inheritance for thelytokous parthenogenesis in Cape honeybees, we determined the sex of the offspring of 74 A. m. capensis workers of a single queen from a colony of the endemic wild population at the Cape of Good Hope Nature Reserve. When we tested individual worker reproduction, parthenogenesis was dimorphic, segregating in a Mendelian fashion supporting the single locus model. We could exclude maternal or paternal effects determining the mode of parthenogenesis. A careful re-analysis of the data of Chapman et al. (2015) also revealed that their data do not contradict the one locus model for the inheritance of thelytoky.