Kin selection and cooperative courtship in wild turkeys

• Published in: Nature Vol. 434; no. 7029; pp. 69 - 72
• Main Author: Krakauer, Alan H
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 03.03.2005
• Subjects: Altruism; Animal behavior; Animal reproduction; Animals; Animals, Wild - physiology; Biological Evolution; Cooperative Behavior; Courtship; Female; Genotype; Male; Meleagris gallopavo; Microsatellite Repeats - genetics; Models, Biological; Reproduction; Reproduction - physiology; Selection, Genetic; Sexual Behavior, Animal - physiology; Turkeys - physiology; Wildfowl
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature03325

In the few species of birds in which males form display partnerships to attract females, one male secures most or all of the copulations. This leads to the question of why subordinate males help in the absence of observable reproductive benefits. Hamilton's concept of kin selection, whereby individuals can benefit indirectly by helping a relative, was a crucial breakthrough for understanding apparently altruistic systems. However in the only direct test of kin selection in coordinated display partnerships, partners were unrelated, discounting kin selection as an explanation for the evolution of cooperation. Here I show, using genetic measures of relatedness and reproductive success, that kin selection can explain the evolution of cooperative courtship in wild turkeys. Subordinate (helper) males do not themselves reproduce, but their indirect fitness as calculated by Hamilton's rule more than offsets the cost of helping. This result confirms a textbook example of kin selection that until now has been controversial and also extends recent findings of male relatedness on avian leks by quantifying the kin-selected benefits gained by non-reproducing males.