Neff Bryan D, Pitcher Trevor E, Ramnarine Indar W
Department of Biology, University of Western Ontario, 1151 Richmond Street, London, ON, Canada.
Mol Ecol. 2008 Jun;17(12):2975-84. doi: 10.1111/j.1365-294X.2008.03816.x. Epub 2008 May 20.
We use microsatellite loci to detail the multiple paternity patterns in broods from 10 wild populations of the guppy (Poecilia reticulata) found in Northern Trinidad. The populations span two major drainages comprising the Caroni and the Oropouche, and include sites that are characterized by either high or low predation. Across the populations the frequency of multiple paternity is high with 95% (range: 70%-100%) of broods having multiple sires. Broods have an average of 3.5 sires (range: 1-9) and a mixed-model analysis suggests that broods from high predation sites have marginally more sires than do those from low predation sites, but this is true only in the Oropouche drainage. There is no difference in sire number between predation sites in the Caroni drainage. Brood size, but not female body length, is correlated with the number of sires and the correlation cannot be attributed solely to the stochastic process associated with sperm competition and a 'fair raffle'. Within broods there is significant skew in reproductive success among males, which may reflect variation in sperm competitiveness or female choice. There is, however, no difference in the skew among populations from different predation regimes or drainages. Finally, high predation populations were characterized by increased genetic variability at the microsatellite loci, suggesting a larger effective population size. We discuss explanations for the high degree of multiple paternity but the general lack of any major differences among broods from ecologically different populations.
我们利用微卫星基因座详细研究了特立尼达岛北部发现的10个野生孔雀鱼（孔雀鱼）种群的多父本模式。这些种群分布在卡罗尼河和奥罗普切河这两个主要流域，包括高捕食风险和低捕食风险的地点。在所有种群中，多父本的频率都很高，95%（范围：70%-100%）的鱼窝有多个父本。每个鱼窝平均有3.5个父本（范围：1-9个），混合模型分析表明，来自高捕食风险地点的鱼窝的父本数量略多于来自低捕食风险地点的鱼窝，但这仅在奥罗普切河流域是如此。卡罗尼河流域的捕食风险地点之间的父本数量没有差异。鱼窝大小与父本数量相关，但雌鱼体长与父本数量无关，而且这种相关性不能仅仅归因于与精子竞争和“公平抽奖”相关的随机过程。在鱼窝内部，雄性之间的繁殖成功率存在显著偏差，这可能反映了精子竞争力或雌鱼选择的差异。然而，来自不同捕食风险状况或流域的种群之间的偏差没有差异。最后，高捕食风险种群的特征是微卫星基因座的遗传变异性增加，这表明有效种群规模更大。我们讨论了多父本程度高的原因，但生态上不同的种群的鱼窝之间普遍缺乏任何重大差异。
