Chromosomal and behavioral studies of MexicanDrosophila. I. Vagility characteristics of three populations ofD. pseudoobscura

Twelve isofemale lines from each of three MexicanDrosophila pseudoobscura populations, known to differ in their degrees of inversion polymorphism, were tested for vagility in the Sakai system. It was found that the flies from the most chromosomally polymorphic population (Zirahuen) had both a significantly lower vagility score and a higher level of expressed genotypic variation for vagility than the flies from the lesser chromosomally polymorphic populations (Amecameca and Tulancingo). The latter two populations could not be distinguished for either parameter of this behavioral trait. The possible role of inversion polymorphism, especially as related to the number of heterozygote combinations formed, in affecting vagility is discussed.