system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: After the mating session, the female black widow spider eats the male. How is this an evolutionary advantage?
gpt
After mating, the male is superfluous to that particular female in ensuring that its offspring are made. So by eating the male, the female steals his calories, thus helping her survive long enough to produce the eggs. But it's been shown that males prefer female black widows that look fat, and thus full from a meal, so they can go after multiple females.