title: The Genetic Relatedness in Groups of Joint-Nesting Taiwan Yuhinas: Low Genetic Relatedness with Preferences for Male Kin.
abstract: The relative importance of direct and indirect fitness and, thus, the role of kinship in the evolution of social behavior is much debated. Studying the genetic relatedness of interacting individuals is crucial to improving our understanding of these issues. Here, we used a seven-year data set to study the genetic structure of the Taiwan yuhina (Yuhina brunneciceps), a joint-nesting passerine. Ten microsatellite loci were used to investigate the pair-wised relatedness among yuhina breeding group members. We found that the average genetic relatedness between same-sex group members was very low (0.069 for male dyads and 0.016 for female dyads). There was also a low ratio of closely-related kin (r>0.25) in the cooperative breeding groups of yuhinas (21.59% and 9.68% for male and female dyads, respectively). However, the relatedness of male dyads within breeding groups was significantly higher than female dyads. Our results suggest that yuhina cooperation is maintained primarily by direct fitness benefits to individuals; however, kin selection might play a role in partner choice for male yuhinas. Our study also highlights an important, but often neglected, question: Why do animals form non-kin groups, if kin are available? We use biological market theory to propose an explanation for group formation of unrelated Taiwan yuhinas.
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.
authors.forename: Mark
authors.initials: M
authors.lastname: Liu
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan; School of Forestry and Resource Conservation, National Taiwan University, Taipei, Taiwan.
authors.forename: Quen-Dian
authors.initials: QD
authors.lastname: Zhong
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.
authors.forename: Yi-Ru
authors.initials: YR
authors.lastname: Cheng
authors.affiliation: Department of Life Science, National Taiwan Normal University, Taipei, Taiwan.
authors.forename: Shou-Hsien
authors.initials: SH
authors.lastname: Li
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.
authors.forename: Shu
authors.initials: S
authors.lastname: Fang
authors.affiliation: Scientific and Technical Research Center Investigation Bureau, Ministry of justice, Hsin-Tien, Taiwan.
authors.forename: Chang-En
authors.initials: CE
authors.lastname: Pu
authors.affiliation: School of Forestry and Resource Conservation, National Taiwan University, Taipei, Taiwan.
authors.forename: Hsiao-Wei
authors.initials: HW
authors.lastname: Yuan
authors.affiliation: Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.
authors.forename: Sheng-Feng
authors.initials: SF
authors.lastname: Shen
mesh_terms: D000818:Animals; D001947:Breeding; D003299:Cooperative Behavior; D019143:Evolution, Molecular; D005260:Female; D008297:Male; D009425:Nesting Behavior; D046109:Passeriformes / Q000235:genetics*; D010375:Pedigree; D010802:Phylogeny