Well they share the function of giving nutrition to the buds and the leaves on the plant , but they preform this function in different way from each other
According to the question, mating between two populations of Rhagoletis produce hybrid flies.
This means that the two population is present in the same habitat or locality, hence they are capable of coming in contact with each other and mate. Hence, the answer cannot be Habitat Isolation.
Mating produces hybrid flies. This is possible when the gametes (egg and sperm) of the two different populations are capable of capable of coming close to each other and undergoing fusion (fertilization). Hence, there is no Mechanical Isolation.
The zygote formed by the above fertilization is capable of developing into healthy hybrid flies with normal life span. Hence, Pre-zygotic Isolation is absent.
But the hybrid flies formed are sterile and not fertile, that is, they are incapable of producing viable gametes which can undergo fertilization and produce a new offspring.Therefore, the eggs laid by the hybrid flies hatch less often. Hence, there is existence of Reduced hybrid fertility.
20 percent available at the highest tropic level. There is less at the top of the food chain because it has ate things from possibly all areas of the food chain and each level is consuming from lower parts of the chain than it. So with the entire food chain eating on what the top eats there is gonna be less for the top