Question

A parasitic species of fly is introduced to one of the Hawaiian islands. This fly deposits its eggs onto chirping crickets, and when the eggs hatch, the larva consume the cricket. In this type of cricket, males have structures on their wings that produce the chirp. Females and some males with a mutation lack this structure on their wings. Which statement predicts the most likely effect of this parasitic fly on future populations of the crickets?

A.
The female crickets in the population will develop the adaptation for chirping.

B.
The cricket population will develop an adaptation to prey on the parasitic flies.

C.
The allele for the nonmutated wings in male crickets will decrease in the population.

D.
The allele for the presence of wings in male crickets will decrease in the population.

Answer 1

C.

The allele for the nonmutated wings in male crickets will decrease in the population.

Step-by-step explanation:

Since the parasitic fly deposits its eggs on chirping crickets and the larvae consume the crickets, it is likely that the crickets with the structures on their wings that produce the chirp (i.e., the nonmutated wings in male crickets) would be more vulnerable to predation by the fly. Over time, this predation pressure would select against crickets with the nonmutated wings, leading to a decrease in the allele frequency for the presence of wings in male crickets in the population.

Option A, which suggests that female crickets will develop the adaptation for chirping, is less likely because the absence of wing structures in females and some males is likely due to a genetic mutation rather than an adaptation that can be acquired during their lifetime.

Option B, which suggests that the cricket population will develop an adaptation to prey on the parasitic flies, is less likely because the introduction of a parasitic species typically takes time for the prey population to develop effective counter-adaptations, if at all.

Option D, which suggests a decrease in the allele for the presence of wings in male crickets, is the most likely outcome as a result of the predation pressure from the parasitic fly.