Complementary sex determination synergistically interacts with extrinsic factors resulting in faster decline and slower recovery of bee populations. I stochastically modelled (Zayed and Packer, 2005) a bee population (N = 10000 bees) experiencing negative growth rates (assumed r = − 0.28) caused by an extrinsic environmental factor. At generation 50, the extrinsic factor was removed allowing the population to recover (assumed r = 0.28). The population size (a), averaged over 100 simulation iterations, and the probability of extinction (b), are presented for populations without diploid male (DM) production, as well as with DM production assuming inviable or effectively sterile DMs. The production of diploid males reduced growth rates below that caused by the extrinsic factor resulting in faster decline and slower recovery (a).