The genetic properties of homosexual copulation behaviour in Tribolium castaneum: artificial selection

Abstract

Summary - Artificial divergent selection for the rate of homosexual copulation (defined as the proportion of homosexual mountings performed by a male in a period of 30 min) has been carried out for 2-3 generations in a population of Tribolium castaneum. A clear response was obtained in each of 4 replicates, corresponding to an overall realized heritability of 0.11 f 0.01. No significant correlated response to selection was observed for the average number of mountings performed by a male during the testing period. Therefore, our results do not agree with evolutionary interpretations of insect homosexual copulation behaviour based on the existence of a negative genetic correlation between the degree of sexual discrimination and sexual activity. On the contrary, they strongly favour the hypothesis of sex recognition being absent in Tribolium casteneum.