Sperm Competition Favors Harmful Males in Seed Beetles
Sperm Competition Favors Harmful Males in Seed Beetles
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DOI：
10.1016/j.cub.2009.01.045
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发表时间：
2009-03-10
期刊：
影响因子：
9.2
通讯作者：
Arnqvist, Goran
中科院分区：
文献类型：
--
作者：
Hotzy, Cosima;Arnqvist, Goran
进化生物学中最神秘的观察之一是一种性别的形态或生理特征的进化，这些特征会对另一种性别的成员造成身体伤害[1-3]。这些特征出现在广泛的分类群中[3]，范围从有毒的射精物质[4-6]到交配期间伤害雌性的生殖器或外部刺[7-11]。目前对这种有害性状的适应性进化的假设完全基于这样的假设，即它们通过帮助生殖竞争而对其携带者有益[1，3]。在这里，我们评估这一关键假设在种子甲虫的生殖器刺在男性身体伤害女性。我们证明，男性脊柱长度与交配过程中对女性的伤害呈正相关，但也表明，男性与脊柱较长的精子竞争更成功。这是第一次完全支持这样一种观点，即通过精子竞争进行的性选择可以有利于雄性的形态特征，从而对雌性造成伤害。然而，我们的研究结果表明，对女性的伤害是一种多效性的副产品，例如男性的生殖器棘通过造成伤害以外的方式提高精子竞争的成功率。
One of the most enigmatic observations in evolutionary biology is the evolution of morphological or physiological traits in one sex that physically injure members of the other sex [1-3]. Such traits occur in a wide range of taxa [3] and range from toxic ejaculate substances [4-6] to genital or external spines that wound females during copulation [7-11]. Current hypotheses for the adaptive evolution of such injurious traits rest entirely on the assumption that they are beneficial to their bearer by aiding in reproductive competition [1, 3]. Here, we assess this key assumption in seed beetles where genital spines in males physically injure females. We demonstrate that male spine length is positively correlated with harm to females during mating but also that males with longer spines are more successful in sperm competition. This is the first complete support for the proposal that sexual selection by sperm competition can favor morphological traits in males that inflict injury upon females. However, our results suggest that harm to females is a pleiotropic by-product, such that genital spines in males elevate success in sperm competition by means other than by causing harm.