title: Fine-scale kin recognition in the absence of social familiarity in the Siberian jay, a monogamous bird species.
abstract: Kin recognition is a critical element to kin cooperation, and in vertebrates, it is primarily based on associative learning. Recognition of socially unfamiliar kin occurs rarely, and it is reported only in vertebrate species where promiscuity prevents recognition of first-order relatives. However, it is unknown whether the recognition of socially unfamiliar kin can evolve in monogamous species. Here, we investigate whether genetic relatedness modulates aggression among group members in Siberian jays (Perisoreus infaustus). This bird species is genetically and socially monogamous and lives in groups that are formed through the retention of offspring beyond independence, and the immigration of socially unfamiliar nonbreeders. Observations on feeders showed that genetic relatedness modulated aggression of breeders towards immigrants in a graded manner, in that they chased most intensely the immigrant group members that were genetically the least related. However, cross-fostering experiments showed that breeders were equally tolerant towards their own and cross-fostered young swapped as nestlings. Thus, breeders seem to use different mechanisms to recognize socially unfamiliar individuals and own offspring. As Siberian jays show a high degree of nepotism during foraging and predator encounters, inclusive fitness benefits may play a role for the evolution of fine-scale kin recognition. More generally, our results suggest that fine-graded kin recognition can evolve independently of social familiarity, highlighting the evolutionary importance of kin recognition for social species.
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Griesser
authors.affiliation: Animal Ecology, Department of Ecology and Genetics, Uppsala University, SE-752 36, Uppsala, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Halvarsson
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
authors.forename: Szymon M
authors.initials: SM
authors.lastname: Drobniak
authors.affiliation: Conservation and Evolutionary Genetics Group, Estación Biológica de Doñana (EBD-CSIC), Seville, Spain.
authors.forename: Carles
authors.identifier: 0000-0002-4206-5246
authors.initials: C
authors.lastname: Vilà
mesh_terms: D000374:Aggression; D000818:Animals; D005075:Biological Evolution; D005260:Female; D008297:Male; D018895:Microsatellite Repeats; D008954:Models, Biological; D046109:Passeriformes / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012919:Social Behavior
keywords: aggression; cooperation; paternity; self-referent phenotype matching; social evolution; social familiarity