Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, United Kingdom;
Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE, United Kingdom.
Proc Natl Acad Sci U S A. 2017 May 16;114(20):5207-5212. doi: 10.1073/pnas.1612235114. Epub 2017 Apr 24.
Kin selection theory predicts that, where kin discrimination is possible, animals should typically act more favorably toward closer genetic relatives and direct aggression toward less closely related individuals. Contrary to this prediction, we present data from an 18-y study of wild banded mongooses, , showing that females that are more closely related to dominant individuals are specifically targeted for forcible eviction from the group, often suffering severe injury, and sometimes death, as a result. This pattern cannot be explained by inbreeding avoidance or as a response to more intense local competition among kin. Instead, we use game theory to show that such negative kin discrimination can be explained by selection for unrelated targets to invest more effort in resisting eviction. Consistent with our model, negative kin discrimination is restricted to eviction attempts of older females capable of resistance; dominants exhibit no kin discrimination when attempting to evict younger females, nor do they discriminate between more closely or less closely related young when carrying out infanticidal attacks on vulnerable infants who cannot defend themselves. We suggest that in contexts where recipients of selfish acts are capable of resistance, the usual prediction of positive kin discrimination can be reversed. Kin selection theory, as an explanation for social behavior, can benefit from much greater exploration of sequential social interactions.
亲缘选择理论预测，在存在亲缘辨别可能性的情况下，动物通常会对更近缘的个体表现出更有利的行为，并对亲缘关系较远的个体表现出直接的攻击性。然而，与这一预测相反，我们提出了一项为期 18 年的野生斑鬣狗研究的数据，表明与优势个体亲缘关系更近的雌性个体特别容易被强制逐出群体，通常会遭受严重的伤害，有时甚至死亡。这种模式不能用避免近亲繁殖或对亲缘关系更密切的个体之间更激烈的局部竞争的反应来解释。相反，我们使用博弈论表明，这种负面的亲缘辨别可以通过选择与亲属无关的目标来解释，以便在抵抗驱逐时投入更多的努力。与我们的模型一致，负面的亲缘歧视仅限于有能力抵抗的老年雌性的驱逐尝试；当试图驱逐年轻雌性时，优势个体没有表现出亲缘歧视，当对无法自卫的脆弱幼崽进行杀婴攻击时，它们也不会在亲缘关系更密切或更疏远的幼崽之间进行区分。我们认为，在接受自私行为的对象有能力抵抗的情况下，通常对正亲缘识别的预测可以被反转。亲缘选择理论作为对社会行为的解释，可以从对连续社会互动的更深入探索中受益。
