In the Drosophila testis, germline stem cells (GSCs) reside within a specialised stem cell niche where they self-renew and produce germ cells that exit the niche and differentiate into mature gametes. Stable associations between GSCs and the testicular somatic cells are essential for GSC cytokinesis and germ cell differentiation. Although it is known that mating can damage germline homeostasis, the immediate effects of mating stress on stem cell populations have been elusive. Now, Kari Lenhart and Tiffany Roach describe how mating affects GSC regulation and tissue homeostasis in the testis of male Drosophila. Firstly, using live imaging, they show that extensive short-term mating increases ecdysone signalling in the somatic cells of the testis, which disrupts/weakens the soma-germline adhesions. Consequently, GSCs progress through early cytokinesis but fail to complete the final step when the daughter cells physically separate, resulting in retention of connected daughter GSCs at the niche and reduced release of differentiating germ cells. The authors also find that these mating-induced defects in GSCs can be resolved when the mating stress is removed. Together, these data suggest that reducing differentiated germ cell release might be adaptive to repeated mating events, providing a mechanism to restore the GSC pool through germ cell de-differentiation.
