UNIDIRECTIONAL INTROGREESION OF A SEXUALLY SELECTED TRAIT ACROSS AN AVIAN HYBRID ZONE: A ROLE FOR FEMALE CHOICE?
UNIDIRECTIONAL INTROGREESION OF A SEXUALLY SELECTED TRAIT ACROSS AN AVIAN HYBRID ZONE: A ROLE FOR FEMALE CHOICE?
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跨鸟类杂交区的性选择性状的单向渐渗：女性选择的作用？
DOI：
10.1111/j.0014-3820.2006.tb01226.x
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发表时间：
2006
期刊：
影响因子：
3.3
通讯作者：
J. Uy
中科院分区：
文献类型：
--
作者：
Adam C. Stein;J. Uy
摘要杂交可以通过形成新的多倍体物种，创造新的遗传变异或作为杂交形式之间潜在的有利性状的管道，成为进化的创造力。后者的证据往往很难找到，因为等位基因在正选择下可以迅速传播到杂交区，并席卷固定。在巴拿马西部，Manacus属两种侏儒鸟之间存在一个鸟类杂交区，在那里明亮的黄色羽毛单向渗入到白色种群中，为杂交区作为优势性状的重要性提供了证据。一些间接证据表明，偏好黄色羽毛的性选择驱动了这种不对称的传播，但缺乏更直接的证据。沿着杂交祖母绿的沿着，黄领和白色领的侏儒鸟都出现在同一个交配场或Leks中，并争夺同一个雌性（“混合Leks”），这为我们提供了一个独特的机会来了解黄色羽毛渐渗的动态。我们研究了这些混合leks，以确定黄色男性是否有交配优势超过白色男性，如果是这样，交配优势是否是由男性-男性的相互作用，女性的选择，或两者兼而有之。我们发现黄色羽毛的雄鸟比白色雄鸟更容易交配，这表明性选择对黄色羽毛的偏爱确实可以解释黄色羽毛的传播。然而，我们发现，这种优势只发生在混合leks的频率黄色男性大于白色男性。这表明，黄色雄虫的优势可能取决于其他黄色雄虫的存在，这可能会减缓在黄色频率低的Leks中的渐渗速率，例如在黄色雄虫开始定殖于白色种群的地区。这一点，沿着混合区主要河流构成的地理障碍，可能会在最初限制或减缓黄色羽毛的传播。最后，我们发现黄色和白色雄性在攻击性和体型方面相似，并且在温顿的位置也相当。由于这些特征或因素通常在侵略性的雄性-雄性相互作用中很重要或由其决定，这些比较表明雄性-雄性相互作用不是黄色羽毛传播的主要机制。然而，白色和黄色男性收到类似的求爱访问的女性，但不同的交配次数，这表明女性积极拒绝白色有利于黄色男性。我们的研究结果表明，由雌性选择的性选择驱动了黄色羽毛在白色种群中的单向渐渗，为杂交区如何作为新的和有利的性状的管道提供了一种机制。
Abstract Hybridization can be an evolutionary creative force by forming new polyploid species, creating novel genetic variation or acting as conduits of potentially advantageous traits between hybridizing forms. Evidence for the latter is often difficult to find because alleles under positive selection can spread rapidly across a hybrid zone and sweep to fixation. In Western Panama, an avian hybrid zone between two species of manakins in the genus Manacus existsw where the unidirectional introgression of bright, yellos plumage into a white population provides evidence for the importance of hybrid zones as conduits of advantageous traits. Several lines of indirect evidence suggest that sexual selection favoring yellow plumage drives this asymmetrical spread, but more direct evidence is lacking. Along the edge of the hybrid zoen, both yello‐ and white‐collared manakins are found in the same mating arenas or leks and compete for the same females (“mixed leks”), provding us with a unique opportunity to understand the dynamics of yellow plumage introgression. We studied these mixed leks to determine whether yellow males have a mating advantage over white males and, if so, whether the mating advantage is drive by male‐male interactions, female choice, or both. We found that yelow males mated more than white males, suggesting that sexual selection favoring yellow males can, indeed, explain the spread of yellow plumage. However, we found that this advantage occurred only in mixed leks where the frequency of yellow males is greater than white males. this suggests that the advantage of yellow males may depend on the presence of other yellow males, which may slow the rate of introgression in leks where yellow frequency is low such as in areas where yellow males are beginning to colonize the white population. This, along with the geographic barrier posed by major rivers in the hybrid zone, may initially limit or slow the spread of yellow plumage. Finally, we found that yelow and white males were similar in aggression and body size, and held comparable positions winthin leks. Because these traits or factors are often important in or dictated by aggressive male‐male interactions, these comparisons indicate that male‐male itneraction is not the primary mechanism for the spread of yellow plumage. However, white and yelow males received similar numbers of courtship visits from females but differed in the number of matings, suggesting that females actively rejected white in favor of yellow males. Our results indicate that sexual selection by female choice has driven the unidirectional introgression of yellow plumage int the white population, providing a mechanism for how hybrid zones act as conduits of novel and advantageous traits.