Simmons Leigh W, Beveridge Maxine, Wedell Nina, Tregenza Tom
Centre for Evolutionary Biology, School of Animal Biology, The University of Western Australia, Crawley, WA 6009, Australia.
Mol Ecol. 2006 Oct;15(12):3817-24. doi: 10.1111/j.1365-294X.2006.03035.x.
Multiple mating is thought to provide an opportunity for females to avoid the costs of genetic incompatibility by postcopulatory selection of compatible sperm haplotypes. Few studies have tested the genetic incompatibility hypothesis directly. Here we experimentally manipulated the compatibility of females with their mates using the gryllid cricket Teleogryllus oceanicus. We recorded the hatching success of eggs laid by females mated with two nonsibling males, two siblings, or one nonsibling male and one sibling. In contrast with two previous studies on crickets that have adopted this approach, the hatching success of eggs did not differ between females mated with two full siblings and females mated with two unrelated males, indicating that embryo viability was not a cost of inbreeding in this species. We assigned paternity to offspring produced by females mated to both a sibling and a nonsibling male using microsatellite markers. As in previous studies of this species, we were unable to detect any difference in the proportion of offspring sired by the 1st and the 2nd male to mate with a female when females were unrelated to their mates. However, in our experimental matings the proportion of offspring sired by the nonsibling male depended on his sequence position. Paternity was biased toward the nonsibling male when he mated first. Our data show that molecular analyses of paternity are essential to detect subtle mechanisms of postcopulatory sexual selection.
多次交配被认为为雌性提供了一个机会，使其能够通过交配后选择相容的精子单倍型来避免遗传不相容的代价。很少有研究直接检验遗传不相容假说。在此，我们利用海洋长颚蟋实验性地操纵了雌性与其配偶之间的相容性。我们记录了与两只非同胞雄性、两只同胞雄性或一只非同胞雄性和一只同胞雄性交配的雌性所产卵子的孵化成功率。与之前采用这种方法的两项关于蟋蟀的研究不同，与两只同胞雄性交配的雌性和与两只非亲缘雄性交配的雌性所产卵子的孵化成功率并无差异，这表明在该物种中胚胎活力并非近亲繁殖的代价。我们使用微卫星标记确定了与一只同胞雄性和一只非同胞雄性交配的雌性所产后代的父系。与之前对该物种的研究一样，当雌性与其配偶无亲缘关系时，我们无法检测到与雌性交配的第一只和第二只雄性所产后代比例的任何差异。然而，在我们的实验交配中，非同胞雄性所产后代的比例取决于其交配顺序。当非同胞雄性首先交配时，父系偏向于他。我们的数据表明，父系的分子分析对于检测交配后性选择的微妙机制至关重要。
