Chromosomal and behavioral studies of Mexican Drosophila. I. Vagility characteristics of three populations of D. pseudoobscura

Intraspecific variation in the effects of mating on emigration activity and fecundity in a natural population of Drosophila melanogaster

Intraspecific variation in the effects of mating on the emigration response behavior and fecundity of Drosophila melanogaster was investigated using isofemale lines of the Himeji population in Japan. The emigration activities of the mated and unmated females were examined with Sakai's population system. The isofemale lines were classified into two groups with respect to the effect of mating on emigration activity; 1) copulation decreased the emigration activity in 26 out of 28 isofemale lines, and 2) higher emigration activity was noted in the mated than in the unmated females in two lines. The percentage of expressed genotypic variance on emigration activity was higher in the unmated females than in the mated ones. Gregarious oviposition did not seem to be related to the decrease of emigration activity in the mated females.

Genetic study on emigration behavior of Drosophila melanogaster in a natural population

Genetic study on emigration behavior of Drosophila melanogaster in the Ishinomaki population was conducted with 140 2nd chromosome lines. Fourteen sets of 5X5 partial diallel cross experiments were made to examine the emigration activity of F1 progeny. Emigration activity was scored using the method of Sakai et al. (1958). Additive genetic variance was 0.0377 +/- 0.0069 and dominance variance 0.0076 +/- 0.0032. The average degree of dominance of mildly deleterious genes for emigration activity in an equilibrium population was 0.069 +/- 0.042. The estimated degree of dominance at a gene locus affecting emigration activity was 0.067, which revealed nearly complete dominance for the tendency of heterozygote flies to move from their original place to another. Average degree of dominance of lethal gene for emigration activity was 0.012.