The effect of another population on emigration behavior of a population.

Abstract

In order to examine the effect of one population on the emigration behavior of another population, seven wild strains of Drosophila melanogaster were used. The SI and KG strain were chosen as tester strain. Single and mixed strain experiments were done, in which two strains were mixed, and three kinds of relative frequencies in the mixtures-0.9, 0.5, and 0.1- were utilized. In mixtures of SI and its neighboring populations, emigration activity was decreased in comparison with the strain in the single condition, but the activity increased when distant populations were mixed. The same tendency was observed in mixtures of KG and other four strains. The increase or decrease in activity was mainly due to the stimulation or diminution of activity in the SI or KG strain. The A/B ratio was also calculated, and it was less than 1.0 in the mixtures of tester strain and its neighbouring populations, while greater than 1.0 in mixtures of tester strain and distant populations. Since A/B ratio is lower when genetically similar populations are mixed, this ratio may be useful to determine genetic relationships among populations.