The intermediate gall sizes produced by gallflies are a result of
i. predatory birds selecting against large galls.
Ii) parasitoid wasps selecting against large galls.
Iii) parasitoid wasps selecting against small galls.
Iv) predatory birds selecting against small galls.

Question

The intermediate gall sizes produced by gallflies are a result of 
i. predatory birds selecting against large galls.
Ii) parasitoid wasps selecting against large galls.
Iii) parasitoid wasps selecting against small galls.
Iv) predatory birds selecting against small galls.

Quizplus · Accepted Answer

The intermediate gall sizes result from a balance of selective pressures: predatory birds tend to prey on larger galls because they are more visible and easier to access, while parasitoid wasps are more likely to infest smaller galls because they are easier to penetrate. This dual pressure selects against both extremes, favoring intermediate sizes.

The Intermediate Gall Sizes Produced by Gallflies Are a Result