IN THE quest to understand a fish’s sexual urges, scientists have been showing sticklebacks the piscine equivalent of soft porn films.
They have found that mating male sticklebacks ejaculate more if they are threatened by would-be Romeos swimming nearby rather than by homely males simply looking after their own eggs.
When sticklebacks mate, a male first builds a nest then, after an elaborate courtship, a female lays her eggs in it and the male ejaculates on the eggs. But often, other males sneak into the nest and ejaculate over the eggs as well. Because of this “sperm competition” to fertilise…
