Published online by Cambridge University Press: 10 July 2009
Assortative mating amongst species of the complex of Anopheles gambiae Giles that occur sympatrically in West Africa was investigated in laboratory mating-choice experiments using dieldrin resistance and hybrid sterility as genetic markers. In competition experiments involving A. gambiae and A. arabiensis Patt., mating was found to be assortative. No effect of cage volume was observed on the operation of the specific mate-recognition system. On the other hand, experiments in which A. gambiae and A. arabiensis were caged separately with A. melas Theo. failed to show the presence of mating barriers known to operate in nature. Similar cage experiments conducted with two different strains of A. gambiae showed that there was no marked mating barrier between the strains. Other experiments showed that hybrid females from the cross between A. gambiae females and A. arabiensis males and the reciprocal cross would mate with both parental types as well as their own males in cages.