Abstract：
Exaggerated sexual traits, such as ornaments and courtship displays, are crucial for mate acquisition in many species and are often subject to directional runaway selection. However, in the face of high predation risk, natural selection can result in a reduction of conspicuous precopulatory displays to avoid detection by potential predators. Sexual selection may then favour increased investment in inconspicuous postcopulatory traits. Here, we investigated the transgenerational effects of predation on precopulatory male courtship and postcopulatory sexual traits (testes size, sperm length) in a dung fly, Sepsis punctum (Sepsidae). Behavioural assays prior to selection document a marked decrease in male courtship displays in the presence of a predator, the Asian Ant Mantis (Odontomantis planiceps). However, after ten generations of experimental evolution, flies exhibited a marked increase in courtship, both in the absence and presence of a predator. Additionally, under sustained predation pressure, male and female body size decreased but male postcopulatory traits were not significantly affected. These results suggest that precopulatory courtship can be under strong sexual selection even in the face of predation pressure. Larger flies were more susceptible to predation, and there could be canalisation of postcopulatory traits that are crucial for fertilisation.
摘要：
夸张的性特征，如装饰品和求爱展示，对于许多物种的配偶获取至关重要，并且经常受到定向失控选择的影响。然而,面对高捕食风险，自然选择可以导致明显的前繁殖显示减少，以避免潜在的捕食者发现。然后，性选择可能有利于增加对不显眼的交配后性状的投资。这里,我们调查了捕食对产前男性求爱和交配后性特征的跨代影响（睾丸大小，精子长度）在粪便中，脓毒症泪点（Sepsidae）。在选择之前的行为分析表明，在存在捕食者的情况下，男性求爱显着减少，亚洲AntMantis(Odontomantisplaniceps)。然而,经过十代实验进化，苍蝇的求爱能力明显增加，无论是在没有捕食者的情况下。此外,在持续的捕食压力下，男性和女性的体型减少，但男性交配后性状未受显着影响。这些结果表明，即使面对捕食压力，催产期前的求偶也可以在强烈的性选择下进行。较大的苍蝇更容易被捕食，并且可能存在对受精至关重要的交配后性状的运河化。关键字。
