A study of guppies has revealed that females show preference for males with rare colors.
Florida State University professor Kimberly Hughes led the research, which is the first to demonstrate such a preference among guppies.
Hughes and her collaborators found that wild male guppies with rare color patterns mate more than their more normally ordained brethren. The rare colored males also, incidentally, tended to live longer.
The researchers pointed out that the males' color variations are genetic, and not related to temperature or diet and that the female guppies didn't show preference for any particular color pattern in their rare mates, just that they were different than the others.
A male guppy placed in a stream with many similar-looking males would not get much attention from females, but the same male placed in a stream with different colored males suddenly made him a rare, desirable mate.
"No matter which color pattern we made rare in any group, they mated more and had more offspring," Hughes said, adding that it's not that the rare colored guppies are trying any harder to mate. All males, regardless of color pattern, go though the same elaborate mating rituals, she said.
She said guppies (Poecilia reticulata) are the perfect species for the study because males' color variations are so visible and because there is so much variation.
"These guys are sort of the champions of variation," Hughes said.
Further studies Hughes plans to conduct will address why female guppies prefer rare-colored males. One hypothesis Hughes wants to explore is whether females guppies - who instinctively want to avoid procreating with a relative - seek differently colored mates to ensure their offspring do not have genetic disorders.
Her research is published in the journal Nature.