A Note on Disruptive Selection Experiments in Drosophila

Disruptive selection with negative assortative mating as well as with opportunity for random mating was carried out for sternopleural bristles in Drosophila melanogaster. In the latter system, the divergence in score between the progeny of high and low females altered little after the fifth generation and was, at the end of 14 generations, much less than expected theoretically. An explanation is suggested for this result, which is paralleled by those of several other workers, in terms of the mating behavior of the females.