Sex and the guppy: females flock together to cope with over-lusty males

Sex and the City: like guppies, below, different types of women band together (AP; Alamy)

If a man without a woman is like a fish without a bicycle, as the feminist slogan has it, can the behaviour of our aquatic ancestors teach us anything about human relations?

Yes, according to scientists who have studied the strategies adopted by females for fending off unwanted male attention. The secret, they say, is to surround yourself with more attractive female friends.

You see this in school playgrounds – a bunch of girls hanging out together who are a mixture of the flirty and the shy, the latter gaining comfort from the protection afforded by their more extrovert and glamorous companions.

Researchers studying a species of small freshwater fish called the Trinidadian guppy found that females chose to swim in groups with others more attractive than themselves and so reduced the constant harassment and frequent mating attempts for which male guppies have a reputation.

The burden on females from the persistent unwanted male advances can be so great that they have difficulty finding food or escaping from predators.

Female guppies are "receptive" to mating for a few days each month during which they emit a sexual pheromone that attracts males. The researchers monitored the fish during both receptive and non-receptive phases and found that when non-receptive they spent more time with receptive females, securing some peace from the advances of the males.

Safi Darden, of the University of Exeter, who led the study published in Proceedings of the Royal Society B, said: "Although we focused our study on one species of fish, I would expect that this strategy would be seen in other species where females face similar levels of unwanted sexual attention from males."