Seasonal variations and balanced polymorphisms in the reproductive potential of temperate D. Melanogaster populations
1987
Boulétreau-Merle, J. | Fouillet, P. | Terrier, O.
Flies from the first generation of isofemale lines of D, melanogaster founded by wild flies collected in spring, summer and autumn in two French populations have been studied for 4 successive years. Cyclical seasonal variations occur in various genetically determined characteristics involved in reproductive potential. The number of ovarioles of the females and female capacity to control oviposition are subject to variation consisting of an increase in frequency of genotypes controlling large number of ovarioles and strong oviposition blocking control in spring and autumn samples. The opposed genotypes (low number of ovarioles and weaker blocking of oviposition control) are favored in summer generations. This balancing selection, induced by temperature variations, modifies temporarily the genetic equilibrium of the population. This enhances the frequency of better adapted genotypes when conditions become less favorable.
显示更多 [+] 显示较少 [-]