Selection for increased sexual bimaturism in the common housefly, <i>Musca domestica</i>

Abstract The growing demand for insect mass production requires methodologies that allow for easy separation of males and females as the two sexes can have very different economic values. The common housefly, Musca domestica (L.) (Diptera: Muscidae), is one of the candidate species for industrial production. In this species, males typically develop faster and are smaller than females. Exploiting housefly sexual bimaturism (sexual difference in developmental time) could allow the maintenance of colonies with a higher proportion of females, which is favourable in terms of egg yield. Here, we report an artificial selection experiment of breeding early‐emerging males with late‐emerging females for six generations, with the aim to increase the time interval between emergence of males and females. The level of sexual bimaturism was not increased after six generations of selection. The life‐history traits fecundity, egg‐to‐adult survival and hatchability were not affected by the selection procedure. Wing size measurement revealed that early‐ and late‐emerging males did not differ in size, suggesting that developmental time and body size are decoupled in this sex. Still, large females consistently emerged later than small females, suggesting an intricate sex‐specific genetic architecture for size and developmental time in the housefly. Our results are relevant in the context of mass production, providing new insight into the manipulation and maintenance of female‐biased sex ratios in production colonies of the common housefly.