 Normally, the workers would work to shift the ratio towards female prevalence, but in the case of "B. ternarius", this would disfavor the workers' evolutionary success.For all hymenopterans, sex is determined by the number of chromosomes an individual possesses.Fertilized eggs get two sets of chromosomes, one from each parent, and so larva develop into diploid females, while unfertilized eggs only contain one set from the mother, so develop into haploid males or drones.