Sperm competition and sexually size dimorphic brains in birds
Sperm competition and sexually size dimorphic brains in birds
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DOI：
10.1098/rspb.2004.2940
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发表时间：
2005-01-22
影响因子：
4.7
通讯作者：
Moller, AP
中科院分区：
文献类型：
--
作者：
Garamszegi, LZ;Eens, M;Moller, AP
自然选择可能有利于性别相似的大脑大小，因为男性和女性有相似的选择压力，而性选择可能导致性别二型大脑。例如，精子竞争涉及行为上的明显性别差异，因为雄性展示，交配守卫和与雌性交配，而雌性在雄性中选择，并请求或拒绝交配。这些行为可能需要两性的根本不同的神经政府，导致性别依赖的大脑进化。在比较研究中使用两种系统发育方法，我们测试了自然和性别选择压力对鸟类大脑大小进化的作用。根据自然选择理论，男性的相对大脑大小与女性的共同进化，这可能是适应类似的环境约束，如喂养创新的结果。然而，不同性别的大脑大小的演变模式不同，与精子竞争相关的因素所反映的额外对父权可能会导致性别大小的二态脑。具体而言，物种中，女性有较大的大脑比男性被发现有较高程度的额外对父子关系独立的潜在的混杂因素，而物种中，男性有相对较大的大脑比女性似乎有较低的额外对父子关系。因此，精子竞争的进化可能会选择复杂的行为，以及相关的神经基质的性别，有更高的潜力，以控制额外的对交配在观察到的水平。因此，性别选择对男性和女性大脑功能的影响可能是不同的。
Natural selection may favour sexually similar brain size owing to similar selection pressures in males and females, while sexual selection may lead to sexually dimorphic brains. For example, sperm competition involves clear-cut sex differences in behaviour, as males display, mate guard and copulate with females, while females choose among males, and solicit or reject copulations. These behaviours may require fundamentally different neural government in the two sexes leading to sex-dependent brain evolution. Using two phylogenetic approaches in a comparative study, we tested for roles of both natural and sexual-selection pressures on brain size evolution of birds. In accordance with the natural-selection theory, relative brain size of males coevolved with that of females, which may be the result of adaptation to similar environmental constraints such as feeding innovation. However, the mode of brain size evolution differed between the sexes, and factors associated with sperm competition as reflected by extra-pair paternity may give rise to sexually size dimorphic brains. Specifically, species in which females have larger brains than males were found to have a higher degree of extra-pair paternity independently of potentially confounding factors, whereas species in which males have relatively larger brains than females appeared to have lower rates of extra-pair paternity. Hence, the evolution of sperm competition may select for complex behaviours together with the associated neural substrates in the sex that has a higher potential to control extra-pair copulations at the observed levels. Brain function may thus be affected differently in males and females by sexual selection.