CHANGE IN SEX-RATIO IN RELATION TO POPULA TION-SIZE IN DROSOPHILA

Changes in sex ratio with population size fluctuations were studied in natural and cage populations of Drosophila. It was shown that the pro portion of females decreased with an increase in population size both in natural and laboratory populations. If laboratory populations were maintained on a poor diet, this effect was absent. The amplitude of nu mber fluctuation was shown to be higher in males than in females. The possible role of density-dependent selection on sex in the control of population size dynamics is discussed.