In the world of pipefish, which are cousins of sea horses, sexual selection may reverse in the most dramatic way yet recorded.
Biologists have most often talked about sexual selection as a force driving males to evolve lures for females. Now, Adam G. Jones from Oregon State University in Corvallis says the Gulf pipefish, Sygnatha scovelli, breaks the pattern.
Like other members of the seahorse family, a female pipefish mates by transferring eggs to a male. He fertilizes the eggs and then carries them to term in a brood pouch.
Females have flashy physiology, such as colorful stripes and deep ridges on their bellies, but males don't. This and the males' pregnancy inspired theorists to predict a looking glass world of females battling for male favor.