Centre for Evolutionary Biology, School of Animal Biology (M092), University of Western Australia, Crawley, Australia.
J Evol Biol. 2011 Feb;24(2):415-21. doi: 10.1111/j.1420-9101.2010.02179.x. Epub 2010 Nov 19.
Mating between close relatives generally results in offspring of decreased fitness. Inbreeding depression is generally greater for life-history traits than for morphological traits, and recent studies of traits subject to sexual selection suggest that these may suffer the greatest inbreeding depression. Sexual selection continues after mating in the form of sperm competition and cryptic female choice, imposing strong selection on male competitive fertilization success. Here, I examine the effects of a single generation of full-sib mating on competitive fertilization success in a cricket, Teleogryllus oceanicus. The estimated coefficient of inbreeding depression in competitive fertilization success was 0.37, higher than that for other life-history and morphological traits. Such intense inbreeding depression coupled with little or no additive genetic variance for this trait is consistent with strong directional selection on male competitive fertilization success generating high levels of dominance variance, and provides an adaptive explanation for the evolution of inbreeding avoidance found in this species.
近亲交配通常会导致后代适应性降低。与形态特征相比，近交衰退在生活史特征上更为普遍，而最近对受性选择影响的特征的研究表明，这些特征可能遭受最大的近交衰退。交配后，以精子竞争和隐蔽雌性选择的形式，性选择会继续存在，对雄性竞争受精成功施加强烈选择。在这里，我检查了在蟋蟀 Teleogryllus oceanicus 中，一代全同胞交配对竞争受精成功的影响。竞争受精成功的估计近交衰退系数为 0.37，高于其他生活史和形态特征的近交衰退系数。这种强烈的近交衰退加上这个特征的加性遗传方差很小或没有，与对雄性竞争受精成功的强烈定向选择一致，这种选择产生了高水平的显性方差，并为该物种中发现的近交回避进化提供了适应性解释。
