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Active Facilitation Of Helper Dispersal By Parents And Siblings In The Cooperatively Breeding Acorn Woodpecker, Natasha D. G. Hagemeyer, Walter D. Koenig, Eric L. Walters
Active Facilitation Of Helper Dispersal By Parents And Siblings In The Cooperatively Breeding Acorn Woodpecker, Natasha D. G. Hagemeyer, Walter D. Koenig, Eric L. Walters
Biological Sciences Faculty Publications
Offspring that delay dispersal in cooperatively breeding species have been hypothesized to gain direct fitness benefits via parental facilitation—being passively tolerated on their natal territory by their parents—thereby enjoying enhanced survival and increased probability of acquiring a breeding position in the population. Here we describe active facilitation in the acorn woodpecker (Melanerpes formicivorus) by parents and siblings assisting the dispersal of helpers in their social group. Helpers in this species compete for reproductive opportunities in “power struggles” that take place when all breeders of one sex die or disappear, creating a reproductive vacancy. Individuals compete at power struggles …
Territory Inheritance And The Evolution Of Cooperative Breeding In The Acorn Woodpecker, Walter D. Koenig, Joseph Haydock, Hannah L. Dugdale, Eric L. Walters
Territory Inheritance And The Evolution Of Cooperative Breeding In The Acorn Woodpecker, Walter D. Koenig, Joseph Haydock, Hannah L. Dugdale, Eric L. Walters
Biological Sciences Faculty Publications
There are two main hypotheses for why offspring in cooperatively breeding taxa delay dispersal and remain on their natal territory rather than disperse. First, ecological constraints may force offspring to remain on their natal territory until a reproductive opportunity presents itself in an otherwise saturated habitat. Alternatively, delaying dispersal and helping kin may increase an offspring's inclusive fitness. One means by which offspring might enhance their direct fitness by delaying dispersal is by inheriting breeding status on their natal territory. Such territory inheritance regularly occurs in acorn woodpeckers, Melanerpes formicivorus, a species whose social groups consist of a cooperatively …
Lifetime Inclusive Fitness Effects Of Cooperative Polygamy In The Acorn Woodpecker, Walter D. Koenig, Sahas Barve, Joseph Haydock, Eric L. Walters
Lifetime Inclusive Fitness Effects Of Cooperative Polygamy In The Acorn Woodpecker, Walter D. Koenig, Sahas Barve, Joseph Haydock, Eric L. Walters
Biological Sciences Faculty Publications
Although over 50 y have passed since W. D. Hamilton articulated kin selection and inclusive fitness as evolutionary explanations for altruistic behavior, quantifying inclusive fitness continues to be challenging. Here, using 30 y of data and two alternative methods, we outline an approach to measure lifetime inclusive fitness effects of cooperative polygamy (mate-sharing or cobreeding) in the cooperatively breeding acorn woodpecker Melanerpes formicivorus. For both sexes, the number of offspring (observed direct fitness) declined while the number of young parented by related cobreeders (observed indirect fitness effect) increased with cobreeding coalition size. Combining these two factors, the observed inclusive …