Egg laying in fruit flies can be triggered (induced) when males deposit their sperm in the spermathecae of the females. What is the selective advantage of induced egg laying for the male flies?
A) Because egg laying is induced upon mating, the males do not have to produce as much sperm.
B) More eggs can be fertilized at once when egg laying is induced.
C) Induced egg laying ensures that a male fly's sperm is used for fertilization.
D) Mating takes less time, so less energy is expended by the males.

Question

Quizplus · Accepted Answer

Induced egg laying ensures that a male fly's sperm is used for fertilization. This is because when egg laying is induced, the female is more likely to use the sperm of the male with whom she has just mated to fertilize her eggs, rather than any sperm that may still be present from previous matings. This provides a selective advantage for the male, as it increases the chances that his genes will be passed on to the next generation.

Egg Laying in Fruit Flies Can Be Triggered (Induced) When