National Geographic : 2015 Aug
In the human social order a male may pursue a female with the help of a “wingman.” In the social order of the Trinidadian guppy (Poecilia reticulata) the female thwarts pursuers with her own sidekick strategy. The female of this small, freshwater fish is receptive to male courtship and mating attempts only at certain times, and gives off a chemical cue when she is. The male, on the other hand, is perpetually randy, and if he encoun- ters a female that’s not giving off the chemical “yes,” he may still attempt copulation. Rather than waste energy fending off these advances, females “would benefit from being able to actively reduce the amount of harassment that they receive,” researcher Safi Darden wrote in a study published in the Proceedings of the Royal Society B. So the females deploy a gal-pal strategy. Those that aren’t looking for sex school around with those that are exuding the eau de yes chemical. “Associating with females more sexually attractive than themselves” helps nonreceptive females dodge unwanted overtures, Darden says. How strong was the uninterested females’ instinct for taking cover behind their sexier sisters? So strong, Darden reports, that during tests in laboratory tanks, the nonreceptive females swam to one part of the tank even though it held no other guppies—because the water there had been laced with the eau de yes scent. —Patricia Edmonds RANGE Native to Brazil, Guyana, Venezuela, and the Caribbean CONSERVATION STATUS Released or escaped into the waters of every continent but Antarctica, this guppy can impact endangered native fish, eating their eggs and carrying parasites. Female guppies avoid unwanted advances by schooling with their sexier sisters. So, Who’s Your Hot Friend? PHOTO: JOEL SARTORE, NATIONAL GEOGRAPHIC CREATIVE A genteel disquisition on love and lust in the animal kingdom Basic Instincts These wild-type guppies (Poecilia reticulata) were photographed at Oklahoma’s Tulsa Zoo.