There is life after death—for guppies. The male Trinidadian guppy, the common aquarium occupant’s wild ancestor, can father offspring long after he goes to his watery grave.
Scientists released 38 males and 38 females into a guppy-free stream in Trinidad; waterfalls on either end of the 100-meter stretch trapped the fish. Every month for a year they captured guppies and analyzed their DNA. Dead dads fathered 73 of the 540 newborns, or nearly 14 percent, and males could breed up to 10 months after they kicked the bucket, the scientists report in Proceedings of the Royal Society B.
Males have females to thank for their awesome reproductive power, since gals store sperm in their ovaries. Both sexes benefit: Males can have babies from beyond the grave, and females, which live longer, can reproduce when guys are in short supply.
“This is a neat reminder that natural selection is not about the survival of the fittest, as it is often portrayed, but about passing on genes to the next generation, dead or alive,” says lead author Andrés López-Sepulcre, a research fellow at the Ecole Normale Supérieure de Paris, in France. “Surviving is just one way of doing that.”
This story originally ran in the November-December 2013 issue as "Staying Power."