Of turkeys and men

A new study shows that turkeys can be just as tribal as humans:

In order to establish which male actually copulated with the female – an activity hard to see in the brush – Krakauer captured, tagged and obtained blood samples from male and female turkeys, and then captured flightless young, scavenged broken egg shells from abandoned nests or lifted eggs from unattended nests to obtain the DNA of offspring. His study included 126 adult turkeys – 51 males and 75 females – and 325 offspring between 1999 and 2004, though only eight of his marked, resident males fathered young.

He found that only the dominant male of a team produced offspring. These dominant males produced, on average, seven offspring over the course of the study, compared to an average solitary male operating on its own, which produced less than one offspring. Because the coalition males were brothers or half brothers, those seven offspring contained a significant proportion of the subordinate male's genes, even though he never bred. (Genetically, because males share half their genes with their brother, two of your brother's offspring contain the same proportion of your DNA as one of your own offspring.)

Krakauer noted that subordinate males probably could have had some breeding success on their own. But this solitary breeding would not offset the advantage of helping a dominant brother. A subordinate male's inclusive fitness – in other words, the net benefit of cooperation – works out to about 1.7 offspring.

"Basically, since subordinate males and dominant males share some proportion of their DNA, the subordinate males benefit indirectly by helping their relative breed," Krakauer said. "A subordinate partner gains more by giving help than it would by going off on its own and trying to breed by itself."

In other words, the more closely related two individuals are the more likely they are to work together for a common cause.

In the news:

In the mating game, male wild turkeys benefit even when they don't get the girl

Wild turkeys find mating success with wingmen, study finds

Turkeys use wingman to get chicks

Turkey mating games challenge theory of 'survival of the fittest'

Around the Blogosphere:

A Literal "Wing Man"

Wingman Addendum

Kin selection and cooperative courtship in wild turkeys