Guppies reproduce from beyond the grave.

GUPPIES REPRODUCE FROM BEYOND THE GRAVE Humans can be forgiven for assuming that successful reproduction requires both partners to be alive. Amazingly, this isn’t the case for the Trinidadian guppy. Under laboratory conditions, female guppies are able to store sperm for up to a year, potentially allowing them to produce offspring even if the males are no longer around. However, several other studies have suggested that the last male to mate with a female ends up fertilizing the bulk of her offspring. This last-male-in advantage may mean that stored sperm is rarely used by guppies in nature. Studying this phenomenon in natural surroundings poses many logistical problems, but in a recent report, Andrés López-Sepulcre and his international team of collaborators not only proved that they were up to the challenge of tackling this problem in the wild but also discovered just how often female guppies use the sperm of deceased mates.