When Female Fruit Flies Mate with Two Different Males on the Same

Question

When female fruit flies mate with two different males on the same day,
A) the first male's sperm fertilizes all of the eggs.
B) the first male's sperm fertilizes most of the eggs.
C) the second male's sperm fertilizes most of the eggs.
D) the first and second males fertilize equal numbers of eggs.
E) none of the eggs become fertilized.

Accepted Answer

In fruit flies, the sperm of the second male to mate with a female fertilizes most of the eggs due to a phenomenon known as "last male precedence." This is a common pattern in many species where the sperm of the last male to mate has a competitive advantage over earlier mates.