Genetic evidence for prevalence of alloparental care in a socially monogamous biparental cichlid fish, Perissodus microlepis, from Lake Tanganyika supports the "selfish shepherd effect" hypothesis.
Genetic evidence for prevalence of alloparental care in a socially monogamous biparental cichlid fish, Perissodus microlepis, from Lake Tanganyika supports the "selfish shepherd effect" hypothesis.
复制标题
DOI：
10.1002/ece3.2089
复制
发表时间：
2016-05
影响因子：
2.6
通讯作者：
Meyer A
中科院分区：
文献类型：
--
作者：
Lee HJ;Heim V;Meyer A
异地照顾--照顾没有血缘关系的幼崽--在动物中很少见，它的生态或进化优势或替代的适应不良性质尚不清楚。我们调查了来自坦噶尼喀湖的社会性一夫一妻制的慈鱼的异地护理，这种鱼表现出双亲照顾。在遗传亲子关系分析中，我们发现在我们调查的所有雏鸟中，以混育、额外配对父亲和额外配对母亲为代表的异地照顾的比例高得惊人。其他亲本的非后代幼体比例为5%~57%，平均为42.8%。遗传亲子关系的分布也表明，这种社会上的一夫一妻制物种实际上有一夫多妻制的交配系统。关于外判和寄养行为的两个不相互排斥的假设可以很好地解释遗传混合幼崽的流行。在大多数幼崽中，父母自己(后代)的后代比领养的(非后代)幼崽的大小明显更大，这支持“自私的牧羊人效应”假说，即养父母优先接受无关的“较小或不较大”的幼崽，因为这将倾向于降低他们自己较大的后代的捕食风险。还有一种趋势是，体型较大的父母，特别是母亲，比较小的父母更倾向于主要照顾自己的后代。体型较大的父母可能更善于抵御绿帽子，并通过外租行为将外国孩子扔进他们的幼崽中。这一结果可能会证明，异位护理对养父母的不良适应影响，只有体型较大、可能更有经验的夫妇才能预防。需要确定的是，为什么这个物种显然没有进化出识别自己幼崽的能力。
Alloparental care – care for unrelated young – is rare in animals, and its ecological or evolutionary advantages or, alternative maladaptive nature, remain unclear. We investigate alloparental care in the socially monogamous cichlid fish Perissodus microlepis from Lake Tanganyika that exhibits bi‐parental care. In a genetic parentage analysis, we discovered a surprisingly high percentage of alloparental care represented by brood mixing, extra‐pair paternity and extra‐pair maternity in all broods that we investigated. The percentage of nondescendant juveniles of other parents, i.e., brood mixing, ranged from 5% to 57% (mean = 28%). The distribution of genetic parentage also suggests that this socially monogamous species has, in fact, polygamous mating system. The prevalence of genetically mixed broods can be best explained by two, not mutually exclusive hypotheses on farming‐out and fostering behaviors. In the majority of broods, the sizes of the parents’ own (descendant) offspring were significantly larger than those of the adopted (nondescendant) juveniles, supporting the ‘selfish shepherd effect’ hypothesis, i.e., that foster parents preferentially accept unrelated “smaller or not larger” young since this would tend to lower the predation risks for their own larger offspring. There was also a tendency for larger parents particularly mothers, more so than smaller parents, to care predominantly for their own offspring. Larger parents might be better at defending against cuckoldry and having foreign young dumped into their broods through farming‐out behavior. This result might argue for maladaptive effects of allopatric care for the foster parents that only larger and possibly more experienced pairs can guard against. It needs to be determined why, apparently, the ability to recognize one's own young has not evolved in this species.