Don’t forget beauty

An ornithologist argues that arbitrary preferences may have a place in the bird world

In an effort to attract choosy females, male birds don vibrant feathers, sing complex melodies and perform attention-grabbing displays. There’s great variety among the males within a species, with some colors being brighter, songs sweeter and performances more pompous.

Among biologists, the prevailing paradigm is that some male traits are downright better than others, indicating reproductive fitness to the female. A suitor with a deep red glow, for instance, may have a better diet, thus be a better forager and thus make a better father to better children.

But when scientists go into a study with this story in mind, they are ignoring part of the picture and biasing their research. “What part of biodiversity has our science failed to describe?” ornithologist Richard Prum of Yale University asked during a lunch talk with science writers November 7 New Haven, Conn. It’s a question for anyone studying sexual selection, he said.

Prum advocates that some female preferences may be arbitrary — perhaps better marketed as “merely a matter of beauty.” Those preferences could coevolve with male traits as opinion in a population changes, one feeding back on the other in a scientifically interesting way, the same way short skirts can come in and out of fashion even though they say nothing about the woman wearer.

Dismissing work that doesn’t find a link between a male trait and the male’s reproductive success does a disservice to the field, Prum said at the ScienceWriters 2010 meeting. Such work doesn’t get published and therefore can’t shape evolving ideas in the field. Studying song repertoire, for example, has gone out of scientific style because it doesn’t conform to the paradigm, he suggested.

So perhaps small-brained subjects have an aesthetic appreciation that big-brained scientists don’t give them credit for.

Elizabeth Quill is former executive editor of Science News. She's now a freelance editor based in Washington, D.C.