Study singles out genes for aggressive, wingmen and cross-dressing birds
VANCOUVER — Plumage is everything in the bird world, and for a certain type of male ruff, scientists have found that genes are responsible for either the black-feathered aggressor, the white wingman or the cross-dressing mimic.
Experts say those traits could hold clues to what's behind aggression in other species, and even humans.
A new study published in the scientific journal "Nature Genetics" identifies the genes responsible for creating the distinctly different male ruff, a wading bird that breeds across Eurasia and winters in Africa.
David Lank, a biologist at Simon Fraser University in Burnaby, B.C., has studied the birds for about 30 years and worked on the study. He said the findings are "a thrill."
About 84 per cent of male ruffs are so-called independents, which have black plumage and fight for their territory. They are the only type of ruff that display aggression, Lank said.
Satellites, which have white plumage, account for about 14 per cent of male ruffs and act as "wingmen" to help the dominant independents attract females to the mating area.
"It's a little like a shopping mall," Lank said. "Why are there 23 shoe stores in the same place? It's because it makes comparison shopping easy."
About one per cent of male ruffs are mimics, which look like female ruffs, are smaller in size and don't have fancy plumage.
Having different kinds of males for one species isn't uncommon in the animal kingdom, Lank said. There are certain types of fish and insects that also have gender variations, but ruffs are unique those differences between males are caused by their genes instead of by the environment.
"It really is an unusual case, but one that is biologically possible, not just theoretically possible, because we have ruffs," Lank said.
Now that scientists have identified the genes, they will begin looking at how they work, he said.
Researchers will also be able to look for similar mechanisms in other species and eventually, that could lead to discoveries about what causes aggression in many different species, including humans, Lank said.
"(In the future) we'll have a much better idea of how the molecular mechanisms work that regulate aggression and male display," he said.
The gene discovery will also allow Lank and other biologists studying ruffs to use blood samples to learn more about the species, including what types of males have been mating at what frequency and why there are so many more independents than mimics.
Gemma Karstens-Smith, The Canadian Press