What female fish wants in males changes over time

Melbourne, Aug 14 (ANI): A new research conducted by Australian scientists has shown that some female fish find different male traits attractive from year to year.

According to the researchers, the changing preferences of female fish may play an important role in evolution.

In the study, lead author Tobi Lehtonen and Dr Bob Wong, of Monash University in Melbourne, gave female sand goby fish the choice of two mates.

"We assessed the preference of the females for male body size and nest construction, which had been shown to be important in guiding female mating preferences," ABC Science quoted Wong as saying.

He said that their study of over four years found that female preferences changed over time.

Wong said while the preference change occurred over generations, the females remained consistent in their mate choice on an individual level.

He said that this study is important because female choice is a strong evolutionary force.

Wong said that evolutionary theory predicts that females always choose the most ornamented males.

But if females only select the most spectacular males then only those males get to breed and pass on their genes and genetic variation would get eroded, Wong said.

"But in nature we don't get that. Cast your eye out at the human population and males don't all have Brad Pitt like features," Wong said.

He said that genetic variation persists despite the strong selection for exaggerated traits.

Wong said that this study has shown that the relative importance of male traits can vary over time.

"What's ideal one year, isn't necessarily the next and this helps genetic variation to persist," he said.

Wong said that scientists are realising more and more that female preferences aren't static.

He said that fluctuation in male traits has been shown in a few other female species.

Wong said that they aren't exactly sure what triggers females to change their preferences over generations, but they suspect environment may be a factor.

"We know from previous studies on a range of different species that mate choice can be influenced by the population density, suitable nesting sites and predation risk," he said.

The study has been published in the Royal Society journal Biology Letters. (ANI)