Knab, Allison, Science & Spirit
ever wished your siblings were more supportive? If so, offer them the case of the wild turkey, where the dominant male's brothers help him get the attention of prospective mates through lavish feather flapping--even at the expense of their own search for companionship.
It's long been observed that, like several other bird species, male turkeys pair up to attract female turkeys through dramatic displays of plumage. But since subordinate males themselves don't usually get to mate, or even inherit a dominant brother's territory when he's done with it, University of California, Berkeley graduate student Alan Krakauer wondered at the reasons behind their behavior.
"The subordinate [male] stands there kind of like a backup singer," said Krakauer, who published his research on the turkeys in a recent edition of the journal Nature. "Cooperation among animals in general is a pretty interesting phenomenon because it goes against how we think of natural selection working. When animals help each other, it becomes a puzzle to figure out why."
Helping out both relatives and nonrelatives theoretically takes away from time that could be spent directly passing on an organism's own genes, so genes for such behavior wouldn't be expected to persist.
But using genetic tests and following a population of more than 100 adult turkeys, Krakauer showed that related males actually increase their inclusive fitness--the proportional number of genes they pass on to the next generation by helping relatives--when they aid their sibling. On average, a subordinate male produces less than one offspring when fending for himself, but by helping attract mates for his brother, the number of genes passed on rises to the equivalent of nearly three offspring. …