What honeybee queen reproduction tells us about germline progenitor phenotypes

The Western honeybee (Apis mellifera)’s pollination and products have been valued at
US$34 billion per year in 2012. Despite the importance of the honeybee to agriculture and pollination, knowledge of their oogenesis and germline is poor. The burden of reproduction
in a hive of honeybees falls on the queen. She is the only member of the hive capable of producing female workers. She alone determines the amount of pollinators and her reproductive success is crucial to the hive’s long-term success. To understand the honeybee germline and how the honeybee queen’s ovary fulfils the demanding reproductive
requirements, we studied somatic and germline cells, cellular division and intercellular bridges, using DAPI and phalloidin staining, in situ Hybridization 3.0 (Hybridization-Chain
Reaction) and immunohistochemistry experiments. We have discovered evidence supporting the origin of oogenesis occurring in a predetermined 8-cell germline cluster. This alternates from what is seen in the model insect Drosophila melanogaster, and other insects. The source of Drosophila’s germline consists of individual germ-stem cells. The 8-cell germline cluster phenotype has been seen in other species across Insecta. Our findings suggest ways in which reproduction in queen bees can be better supported and further our understanding of germline stem cell regulation. Our data allows us to explore germline phenotypes and consider whether phylogeny or ecology is responsible for the different phenotypes. Our research highlights an understudied model reproductive system among insects.