Griesser Michael, Halvarsson Peter, Drobniak Szymon M, Vilà Carles
Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
Animal Ecology, Department of Ecology and Genetics, Uppsala University, SE-752 36, Uppsala, Sweden.
Mol Ecol. 2015 Nov;24(22):5726-38. doi: 10.1111/mec.13420. Epub 2015 Nov 6.
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.
亲缘识别是亲缘合作的关键要素，在脊椎动物中，它主要基于联想学习。对社交上不熟悉的亲属的识别很少发生，仅在滥交行为妨碍对一级亲属识别的脊椎动物物种中有相关报道。然而，在一夫一妻制物种中，对社交上不熟悉的亲属的识别是否能够进化尚不清楚。在此，我们研究了遗传相关性是否会调节西伯利亚松鸦（Perisoreus infaustus）群体成员之间的攻击性。这种鸟类在基因和社会层面上都是一夫一妻制的，它们生活的群体是通过后代在独立后仍留居以及社交上不熟悉的非繁殖个体的迁入而形成的。对喂食器的观察表明，遗传相关性以一种分级的方式调节繁殖者对迁入者的攻击性，即它们对遗传关系最远的迁入群体成员追逐得最为激烈。然而，交叉养育实验表明，繁殖者对自己的雏鸟和在雏鸟期就被交换的交叉养育的雏鸟同样宽容。因此，繁殖者似乎使用不同的机制来识别社交上不熟悉的个体和自己的后代。由于西伯利亚松鸦在觅食和遭遇捕食者时表现出高度的裙带关系，内含适合度益处可能在精细尺度的亲缘识别进化中发挥作用。更普遍地说，我们的研究结果表明，精细分级的亲缘识别可以独立于社会熟悉度而进化，突出了亲缘识别对群居物种的进化重要性。
