What is the most likely factor constraining body size in Drosophila at current levels of oxygen?

Question

Quizplus · Accepted Answer

Stabilizing selection is the most likely factor constraining body size in Drosophila at current levels of oxygen. Stabilizing selection favors individuals with intermediate traits and acts to reduce variation in a population, which results in a narrower range of body sizes. This is likely the case for Drosophila because larger body size requires more oxygen to maintain, while smaller body size results in reduced mobility and feeding efficiency. Therefore, stabilizing selection acts to maintain an optimal body size that balances the advantages and disadvantages of larger or smaller body sizes in current oxygen conditions.

What Is the Most Likely Factor Constraining Body Size in Drosophila