The Guppy Dating Game

When it comes to breeding, guppies treasure their ugly friends - because they make them look so good by comparison! Similarly, why would any man want to hang out with George Clooney or Brad Pitt if you're looking for love? 

Recent studies of male guppies have shown that certain males prefer to associate themselves with other drab-colored counterparts when females are around. By doing this, these males actively choose the social context that maximises their relative attractiveness! With the notion of 'if you are surrounded by ugly friends, you look better' attitude. 

The studies, carried out at the University of Padua, Italy, built their theory on a kind of 'guppy dating game'. These experiments consisted of one female being placed in a partitioned section at either end of an aquarium. Guppy 'bachelorette No.1' had two attractive, brightly-coloured males placed on either side of her. Guppy 'bachelorette No.2' was stuck with uglier, drab-coloured fish. When a male guppy was put in the middle of the tank, and given the choice of which female to sidle up to, 'Bachelorette No.2' (with the 'uglier' males) was the more popular pick, with male guppies spending about 62% of their time hanging around her side of the aquarium.

The research also found that the time the male guppies spent with 'bachelorette No.2' correlated with her companion's unattractiveness. The uglier the guppy, the less likely it was that he would hang around the brightly-coloured model-like males placed next to 'bachelorette No.1'.

As it could be argued that that guppies avoided their brightly coloured friends, either because attractive fish were more aggressive, or predators were more likely to spot them, the experiment was repeated. Researchers ran the tests without any females, and then again with the lights in the male enclosures dimmed so that the test guppies could not see them clearly. The results of these extra experiments concluded that both aggression or predation weren't a factor in their choice.

The guppy (Poecilia reticulata), also known as the 'millionfish', is one of the most popular freshwater aquarium fish species in the world. It is one of the smaller members of the Poeciliidae family (with females measuring 4 - 6cm, and males 2.5 - 3.5cm) and like all other members of this family are highly prolific livebearers. The gestation period of a guppy is 21–30 days, with this varying according to the water temperature (guppies prefers a hard water aquarium with a temperature between 72°F and 82 °F). The female guppy can have between 2 and 50 fry at a time, but this most typically ranges between 5 and 30. After giving birth, the female is ready for conception again within only a few hours! In fact female guppies have the ability to store sperm up to a year, so they can give birth many times without depending on the presence of a male. 

From the moment of birth, each fry is a perfect miniature version of it's parents, being fully capable of swimming, eating, and avoiding danger. 

Guppies are native to Antigua and Barbuda, Barbados, Brazil, Guyana, Jamaica, the Netherlands Antilles, Trinidad and Tobago, the U.S. Virgin Islands and Venezuela. However, guppies have been introduced to many different countries on all continents. Sometimes this has occurred accidentally, but most often as a means of mosquito control, with the hope being that the guppies would eat the mosquito larvae and therefore slow any potential spread of malaria.