Patterns of sperm precedence and predictors of paternity in the Trinidadian guppy
Patterns of sperm precedence and predictors of paternity in the Trinidadian guppy
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DOI：
10.1098/rspb.2000.1577
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发表时间：
2001-04-07
影响因子：
4.7
通讯作者：
Magurran, AE
中科院分区：
文献类型：
--
作者：
Evans, JP;Magurran, AE
尽管精子竞争在动物中广泛存在，但在有限的类群中进行了研究。在这方面最被忽视的群体是体内受精鱼，在这一群体中，人们对精子竞争的动态几乎一无所知。在这项研究中，我们研究了处女雌性孔雀鱼与两只雄性孔雀鱼交配时精子竞争的结果。行为线索被用来确保每个雄性交配一次(与雌性合作)，并确保精子在交配时成功受精。利用两个多态微卫星基因座估计了二雄(P-2)后代的比例，结果表明，这两个微卫星座位呈双峰型分布，第一雄性优先或(更多)第二雄性优先。观察到的P-2分布与“公平抽奖”精子竞争模型下的预期不同。因此，随机的精子混合不太可能解释本研究中观察到的P-2的差异。我们研究的另一个目的是确定男性生殖成功的预测因素。使用Logistic线性模型，我们发现第一次和第二次男性之间的父子关系最好的预测因素是交配时间和求爱表现率的差异。交配速度快、乙状结肠显示次数相对较多的雄性，比那些交配速度较慢、精力较弱的雄性获得了更多的亲子关系。由于雌性被高展示的雄性所吸引，我们的结果表明雌性的选择可能会促进孔雀鱼的精子竞争和/或精子的选择。
Despite its widespread occurrence in animals, sperm competition has been studied in a limited range of taxa. Among the most neglected groups in this respect are internally fertilizing fish in which virtually nothing is known about the dynamics of sperm competition. In this study, we examined the outcome of sperm competition when virgin female guppies mated with two males. Behavioural cues were used to ensure that each male mated once (with female cooperation) and that sperm were successfully inseminated at copulation. Two polymorphic microsatellite loci were used to estimate the proportion of offspring sired by the second male (P-2) and the results revealed a bimodal distribution with either first or (more often) second male priority. The observed P-2 distribution differed from that expected under the 'fair raffle' model of sperm competition. Random sperm mixing is therefore unlikely to account for the observed variance in P-2 in this study. A further aim of our study was to identify predictors of male reproductive success. Using logistic linear modelling, we found that the best predictors of paternity were time to remating and the difference in courtship display rate between first and second males. Males that mated quickly and performed relatively high numbers of sigmoid displays obtained greater parentage than their slower and less vigorous counterparts. Since females are attracted to high-displaying males, our results suggest that female choice may facilitate sperm competition and/or sperm choice in guppies.