Drosophila pseudoobscura and D. persimilis are two species of flies that live in the western United States. The geographic range of D. persimilis, which is much smaller than that of D. pseudoobscura, is enclosed within the range of D. pseudoobscura. Findings by Mohamed Noor and others show that D. pseudoobscura taken from areas that overlap with D. persimilis are less likely to mate with D. persimilis than are the D. pseudoobscura flies from populations that do not experience D. persimilis. What is the most likely explanation for these results?

Question

Quizplus · Accepted Answer

Reinforcement suggests that natural selection promotes prezygotic isolation between populations that overlap, to minimize the formation of unfit hybrid offspring. In this case, D. pseudoobscura from overlapping areas have evolved to avoid mating with D. persimilis, which is likely due to selection for prezygotic isolation between the two species, leading to reinforcement. Temporal isolation, the Dobzhansky-Muller model, the Darwin effect, and adaptive radiation are not the most likely explanations for these results.

Drosophila Pseudoobscura and D