"Long before it's in the papers"
June 04, 2013


Fish may avoid “sexual harassment,” researchers say

June 9, 2005
Courtesy University of Wales Bangor
and World Science staff

Sexual harassment is an increasingly sensitive issue, as women in growing numbers turn to the courts to protect them from aggressive sexual advances. 

Guppies, especially males, come in a dazzling array of colors. The guppies above come from Trinidad, where researchers recently found that females sometimes appear to avoid "sexual harassment" by males. The fish at bottom right is a female; the rest are males. Guppies are small freshwater fish native to the Caribbean and South America. (Image courtesy pbs.org)

Now, scientists say, the matter may be about to take on proportions beyond the merely human. 

The researchers have reported evidence that some female guppies, a popular aquarium fish, risk their lives to avoid unwanted male attention.

The study, by Darren Croft of the University of Wales, Bangor, and colleagues, appears in the June issue of the research journal American Naturalist.

Male guppies constantly pester females for sex, displaying their colors in mating dances and battling each other for access to the females.

But if all this fails to impress a desired female, the male “will attempt to sneak a mating with her when she is not looking,” Croft said. Guppy sex is very quick.

Among guppies, as with many vertebrates, “it is the males that ‘dress to impress,’” Croft added. “Male guppies have bright colour patterns they use to attract females, whilst females are a dull brown colour. But the bright colours of males also attract the attention of predators.”

The scientists found that female guppies might use this to their advantage—venturing into deep water where predators lurk, and where it’s too dangerous for males to follow. The females thus avoid male attention, but risk being eaten.

In many animal species, males and females tend to live in different types of habitats, a phenomenon known as sexual segregation, Croft said.

“Sexual segregation is not restricted to fish; it is often found in deer and antelopes, and may even occur in humans,” continued Croft. “Ancient Greek mythology tells of a nation of female warriors known as the Amazons who lived on an island. The Amazons only met with men to trade and reproduce, and kept all daughters on the island.”

Although the legend’s truth is debatable, “sex differences in habitat use are common,” he added. “Understanding why and how this behaviour occurs is essential if we are going to conserve and protect species and habitats.”

In many areas, he added, predators are the first to go extinct. This often has unexpected ripple effects. For guppies, he said, females “may suffer more sexual harassment.”

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