Evolution of Increased "Female Sex Ratio" in the Blowfly (Phaenicia sericata) Under Laboratory Competition with the Housefly (Musca domestica)

Publisher Website
Google Scholar
Abstract
Both species were kept together in competition in a 16 -cell population cage. The adults were censused weekly, and the sex ratio of a sample determined periodically. Musca went to extinction between the 64 and 65 censuses. The cage was discontinued at the 69 census. Significant preponderances of Phaenicia female adults were observed in the population cage after one half year. This preponderance of females was not temporary and merely existent during the pressure of competition, since first generation Phaenicia descendants of the terminated cage population reared in uncrowded conditions also had a high female sex ratio which was not significantly different from that observed in the Phaenicia population in the cage except during one census. Furthermore, the sex ratio at emergence of wild stock Phaenicia from larvae reared under intraspecific competition during one generation did not change from its normal condition. This ratio was significantly different from Phaenicia descendants of the cage population reared in the absence of competition. It was concluded that a higher female sex ratio at emergence evolved in the Phaenicia population in the population cage. Since both species have polygamous males this would have been advantageous under the severe interspecific competitive conditions existing.

This publication has 0 references indexed in Scilit: