The effect of population size on effective population size: An empirical study in the red flour beetle Tribolium castaneum

Abstract

Despite the increasing number of studies on the magnitude of N(e)/N ratios, much remains unknown about the effects of demographic and environmental variables on N(e)/N. We determined N(e)/N for seven population size treatments, ranging from N = 2 to N = 960, in the red flour beetle Tribolium castaneum. N(e)/N decreased with increasing N, as evidenced by a significant negative relationship between logN and N(e)/N. Our results are consistent with other published data on the relationship between N(e)/N and N. Effective population sizes in large populations may be much smaller than previously recognized. These results have important implications for conservation and evolutionary biology.