The populational effects of inbreeding in tribolium

Abstract

Replicated populations of the flour beetle, Tribolium castaneum, were reared under nine population structures consisting of combinations of three effective population sizes and three interdemic migration rates. For each treatment, the expected loss of genetic variance within demes owing to the cumulative effects of finite population size was calculated and related to observed changes in density-dependent population growth rates. A strong positive correlation was demonstrated between the predicted decline in within-deme genetic variarce and the degree to which a deme's rate of increase declined over time. Notably, changes in the rate of population increase could be detected when the predicted loss in genetic variance was as low as 10 per cent. © 1981 The Genetical Society of Great Britain.