Beckoning the Beautiful. Female insects that choose good-looking mates die young but make the population grow fast.

Being Picky Pays Off

It turns out that handsome dudes can be more than just high-maintenance ornaments. A new study shows that female house crickets who choose more attractive mates end up with more offspring than peers who take the homely ones, suggesting that the benefits outweigh the costs when gals pick hunks.

Attractive males are presumably more genetically fit, but they can also make their mate's life hard by doing things like breeding with other females instead of helping raise the young. Most scientists currently think these costs couldn't possibly be worth future benefits such as better representation for mom in the gene pool. But researchers usually measure one fitness trait per experiment.

University of New South Wales evolutionary biologist Megan Head and colleagues wanted to measure fitness more comprehensively. First, the team figured out which male crickets appealed to the babes. They did this by putting pairs of crickets together and timing how long it took the female to mount the male. The researchers assumed that the faster mom hopped on pop, the more attractive the male. They then hooked up 40 females with pleasing males and 40 females with unattractive ones. The team measured various direct costs, such as how long the female lived after bearing offspring, and indirect benefits, such as how attractive her offspring grew up to be.

The only significant difference the researchers found when considering traits individually was that female insects who mated with hot males died on average 4 days earlier than those stuck with the unattractive ones. But when the researchers combined all the measures of fitness such as generation time, survival, and attractiveness or fertility of offspring, they found that attractive mates allowed females to grow their clan 25% faster than homely mates did. The team reports its findings in next month's issue of Public Library of Science Biology.

"This is the very first experimental demonstration" that females benefit from being choosy, says evolutionary biologist Tommaso Pizzari of the University of Oxford, U.K., and "sheds some new light on the adaptive significance of female preference."

Related sites
Megan Head's website
The report at PLoS Online

Posted in Evolution, Biology