Crozier's Effect and the Acceptance of Intraspecific Brood Parasites
Crozier's Effect and the Acceptance of Intraspecific Brood Parasites
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DOI：
10.1016/j.cub.2018.08.014
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发表时间：
2018-10-22
期刊：
影响因子：
9.2
通讯作者：
Foster, William A.
中科院分区：
文献类型：
--
作者：
Field, Jeremy;Accleton, Chris;Foster, William A.
生物体通常可以通过区分不同类别的个体而受益。一个例子是亲属识别，即个体优先与具有匹配识别线索但拒绝其他人的遗传亲属联系或帮助。尽管有潜在的好处，但是，使用遗传线索的亲属识别通常很弱或不存在[1-4]。一个被称为“克罗齐效应”的一般解释是，当个体随机相互作用时，更罕见的线索等位基因不太匹配其他个体的线索，因此主要参与“拒绝”型相互作用。如果这种相互作用的代价更高，那么积极的频率依赖性选择就会侵蚀辨别力所依赖的线索多样性[4，5]。虽然被广泛引用[1，2，4，6-9]，但这一想法缺乏严格的实地测试。在这里，我们展示了如何克罗齐效应适用于主机和同种寄生虫之间的相互作用，并使用现场数据进行测量。在我们研究的黄蜂中，同种寄生符合克罗齐模型的一个关键假设：同一只雌性既是宿主又是寄生虫。通过在巢穴之间交换后代的实验，我们没有发现任何证据表明雌性对与外国后代相关的遗传线索做出反应。然而，通过测量成本和收益，我们证明了一个强大的克罗齐效应：因为更多的父母投资被浪费时，外国后代被拒绝，涉及拒绝的相互作用比涉及接受的相互作用有显着较低的回报。因此，代价高昂的排斥可以通过对罕见的线索等位基因进行选择来消除线索多样性，这与我们观察到的缺乏基于遗传的识别相一致。相反，雌性似乎依赖于非遗传线索，使它们能够检测到不到一半的寄生后代。
Organisms can often benefit by distinguishing between different classes of individuals. An example is kin recognition, whereby individuals preferentially associate with or aid genetic relatives that bear matching recognition cues but reject others. Despite its potential benefits, however, kin recognition using genetically based cues is often weak or absent [1-4]. A general explanation, termed "Crozier's effect," is that when individuals interact randomly, rarer cue alleles less often match cues of other individuals, and so are involved predominantly in "reject"-type interactions. If such interactions are more costly, positive frequency-dependent selection will erode the cue diversity upon which discrimination depends [4, 5]. Although widely cited [1, 2, 4, 6-9], this idea lacks rigorous testing in the field. Here, we show how Crozier's effect applies to interactions between hosts and conspecific parasites, and measure it using field data. In the wasp we studied, conspecific parasitism fits a key assumption of Crozier's model: the same females act as both hosts and parasites. By exchanging offspring between nests experimentally, we find no evidence that females respond to genetically based cues associated with foreign offspring. Through measuring costs and benefits, however, we demonstrate a strong Crozier effect: because more parental investment is wasted when foreign offspring are rejected, interactions involving rejection have substantially lower payoffs than interactions involving acceptance. Costly rejection can thus eliminate cue diversity by causing selection against rare cue alleles, consistent with the absence of genetically based recognition that we observe. Females instead appear to rely on non-genetic cues that enable them to detect less than half of parasitic offspring.