Department of Ecology, Evolution and Organismal Biology, University of California, Riverside, CA 92507, USA.
J Evol Biol. 2010 Nov;23(11):2309-23. doi: 10.1111/j.1420-9101.2010.02085.x. Epub 2010 Sep 28.
In animal populations, sib mating is often the primary source of inbreeding depression (ID). We used recently wild-caught Drosophila melanogaster to test whether such ID is amplified by environmental stress and, in males, by sexual selection. We also investigated whether increased ID because of stress (increased larval competition) persisted beyond the stressed stage and whether the effects of stress and sexual selection interacted. Sib mating resulted in substantial cumulative fitness losses (egg to adult reproduction) of 50% (benign) and 73% (stressed). Stress increased ID during the larval period (23% vs. 63%), but not during post-stress reproductive stages (36% vs. 31%), indicating larval stress may have purged some adult genetic load (although ID was uncorrelated across stages). Sexual selection exacerbated inbreeding depression, with inbred male offspring suffering a higher reproductive cost than females, independent of stress (57% vs. 14% benign, 49% vs. 11% stress).
在动物种群中，兄妹交配通常是近亲繁殖衰退（ID）的主要来源。我们使用最近野外捕获的黑腹果蝇来测试这种 ID 是否会被环境压力放大，以及在雄性中是否会被性选择放大。我们还研究了由于压力（增加幼虫竞争）而增加的 ID 是否会持续到压力阶段之外，以及压力和性选择的影响是否相互作用。兄妹交配导致的累积适合度损失（从卵到成虫的繁殖）高达 50%（良性）和 73%（应激）。压力增加了幼虫期的 ID（23%比 63%），但在应激后生殖阶段没有增加（36%比 31%），这表明幼虫期的压力可能已经清除了一些成年的遗传负荷（尽管 ID 在不同阶段之间没有相关性）。性选择加剧了近亲繁殖的衰退，与非近亲繁殖的雄性后代相比，近亲繁殖的雄性后代的生殖代价更高，而与压力无关（良性 57%比 14%，应激 49%比 11%）。
