[Campbell Biology P.1198] According to Figure 51.13 and the accompanying text, which of the f... | Practice Question

According to Figure 51.13 and the accompanying text, which of the following statements about Drosophila melanogaster foraging behavior is correct?

  • A: Larvae from high population density (K1-K3) exhibit shorter mean path lengths, and this behavior is favored by the forS allele.
  • B: The forS allele is prevalent in low-density populations, which forage over shorter distances, while the forR allele is prevalent in high-density populations, which forage over longer distances.
  • C: All Drosophila populations evolve to forage over uniformly long distances, regardless of population density, to maximize food intake.
  • D: Low population density promotes longer foraging paths, as food becomes scarce, and this is linked to the forR allele.

Explanation

Figure 51.13 shows that larvae from low population density R1-R3 have significantly shorter mean path lengths than those from high population density K1-K3 . The text further explains that the forS allele increased in frequency in low-density populations, leading to shorter foraging, while the forR allele increased in frequency in high-density populations, leading to longer foraging. This indicates that shorter paths are adaptive in low density where food is sufficient, and longer paths are adaptive in high density to find depleted food.