Department of Biology, University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada.
Proc Biol Sci. 2010 Mar 22;277(1683):885-94. doi: 10.1098/rspb.2009.1639. Epub 2009 Oct 28.
In many species females prefer major histocompatibility complex (MHC) dissimilar mates, which may improve offspring resistance to pathogens. However, sexual conflict may interfere with female preference when males attempt to mate with all females, regardless of compatibility. Here we used semi-natural spawning channels to examine how mating behaviour and genetic similarity at the MHC class II peptide binding region affected parentage patterns in Chinook salmon (Oncorhynchus tshawytscha). We found that females directed aggression at more MHC-similar males than expected by chance, providing a possible mechanism of female MHC choice in salmon. Males also directed aggression towards MHC-similar females, which was consistent with males harassing unreceptive mates. Males' aggression was positively correlated with their reproductive success, and it appeared to overcome female aversion to mating with MHC-similar males, as females who were the target of high levels of male aggression had lower than expected MHC divergence in their offspring. Indeed, offspring MHC divergence was highest when the sex ratio was female-biased and male harassment was likely to be less intense. These data suggest that male harassment can reduce female effectiveness in selecting MHC-compatible mates, and sexual conflict can thus have an indirect cost to females.
在许多物种中，雌性更喜欢 MHC 不同的配偶，这可以提高后代对病原体的抵抗力。然而，当雄性试图与所有雌性交配，而不考虑相容性时，性冲突可能会干扰雌性的偏好。在这里，我们使用半自然产卵通道来研究交配行为和 MHC 类 II 肽结合区的遗传相似性如何影响奇努克鲑鱼（Oncorhynchus tshawytscha）的亲子关系模式。我们发现，雌性对 MHC 相似的雄性的攻击比对机会预期的更多，这为鲑鱼的雌性 MHC 选择提供了一个可能的机制。雄性也对 MHC 相似的雌性发起攻击，这与雄性骚扰不接受的雌性一致。雄性的攻击与它们的繁殖成功呈正相关，而且似乎克服了雌性对与 MHC 相似的雄性交配的厌恶，因为那些成为高水平雄性攻击目标的雌性的后代 MHC 差异低于预期。事实上，当性别比例偏向雌性且雄性骚扰可能不那么强烈时，后代 MHC 的差异最大。这些数据表明，雄性骚扰可以降低雌性选择 MHC 相容配偶的有效性，因此性冲突可能会对雌性产生间接成本。
