THE GENETIC PROPERTIES OF HOMOSEXUAL COPULATION BEHAVIOR IN TRIBOLIUM-CASTANEUM - ARTIFICIAL SELECTION

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 p opulation of Tribolium castaneum. A clear response was obtained in eac h of 4 replicates, corresponding to an overall realized heritability o f 0.11 +/- 0.01. No significant correlated response to selection was o bserved for the average number of mountings performed by a male during the testing period. Therefore, our results do not agree with evolutio nary interpretations of insect homosexual copulation behaviour based o n the existence of a negative genetic correlation between the degree o f sexual discrimination and sexual activity. On the contrary they stro ngly favour the hypothesis of sex recognition being absent in Triboliu m casteneum.