title: Inclusive-fitness logic of cooperative breeding with benefits of natal philopatry.
abstract: In cooperatively breeding species, individuals help to raise offspring that are not their own. We use two inclusive-fitness models to study the advantage of this kind of helpful behaviour in social groups with high reproductive skew. Our first model does not allow for competition among relatives to occur but our second model does. Specifically, our second model assumes a competitive hierarchy among nest-mates, with non-breeding helpers ranked higher than their newborn siblings. For each model, we obtain an expression for the change in inclusive fitness experienced by a helpful individual in a selfish population. The prediction suggested by each expression is confirmed with computer simulation. When model predictions are compared to one another, we find that helping emerges under a broader range of conditions in the second model. Although competition among kin occurs in our second model, we conclude that the life-history features associated with this competition also act to promote the evolutionary transition from solitary to cooperative breeding.
authors.affiliation: Department of Applied Mathematics, The University of Western Ontario, , London, Ontario, Canada , N6A 5B7.
authors.forename: Geoff
authors.initials: G
authors.lastname: Wild
authors.forename: Cody
authors.initials: C
authors.lastname: Koykka
mesh_terms: D000818:Animals; D005075:Biological Evolution; D003163:Competitive Behavior / Q000502:physiology; D003198:Computer Simulation; D003299:Cooperative Behavior; D056084:Genetic Fitness / Q000502:physiology*; D008954:Models, Biological; D009425:Nesting Behavior / Q000502:physiology*; D011157:Population Dynamics; D013731:Territoriality
keywords: alloparental care; delayed dispersal; helpers-at-the-nest; kin selection; social evolution; theory