Speciation in Brood Parasitic Indigobirds

巢寄生靛蓝鸟的物种形成

• 批准号: 0089757
• 负责人: Michael Sorenson
• 金额: $ 26.97万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-02-15 至 2005-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0089757&HistoricalAwards=false
• 关键词: Speciation; Brood; Parasitic; Indigobirds

Sorenson0089757The African indigobirds (genus Vidua) are obligate brood parasites, reproducing only by laying their eggs in the nests of other species. Indigobirds are highly host-specific and the young parasites precisely mimic the mouth colors and patterns in the young of their respective hosts. As adults, male indigobirds mimic the songs of their hosts. This behavior results in the genetic cohesion of indigobird species because females also imprint on the host species and choose their mates based on song. These same behavioral mechanisms, however, may result in reproductive isolation and rapid speciation after the colonization of a new host species. This research will use molecular genetic markers to investigate the evolutionary history and genetic structure of indigobird species and populations using samples from over 500 indigobirds collected throughout Africa. In addition, an intensive field study in Cameroon will directly evaluate the incidence of ongoing hybridization and genetic introgression among indigobird populations using different hosts.The indigobird system is a remarkable example of rapid evolutionary diversification and adaptive evolution and represents one of those unusual situations in which the evolutionary process can be studied in progress. This research will contribute to a renewed interest among evolutionary biologists in the mechanisms of speciation and the roles of natural and sexual selection in generating biodiversity. A clear understanding of the evolutionary history and genetic structure of indigobird populations will also lay the groundwork for future analyses of the genetic and developmental mechanisms underlying mouth mimicry, the key genetic adaptation of these host-specific brood parasites.

索伦森0089757非洲靛蓝鸟（属Vidua）是专性育雏寄生虫，仅通过在其他物种的巢中产卵繁殖。靛蓝鸟具有高度的宿主特异性，年轻的寄生虫精确地模仿各自宿主年轻时的嘴的颜色和图案。成年后，雄性靛蓝鸟模仿它们的主人的歌声。这种行为导致了靛蓝鸟物种的遗传凝聚力，因为雌性也会在宿主物种上留下印记，并根据歌声选择配偶。然而，这些相同的行为机制，可能会导致生殖隔离和快速物种形成后，一个新的宿主物种的殖民化。这项研究将使用分子遗传标记，利用从非洲各地收集的500多只靛蓝鸟的样本，调查靛蓝鸟物种和种群的进化历史和遗传结构。此外，在喀麦隆进行的一项深入实地研究将直接评估使用不同寄主的靛蓝鸟种群之间正在进行的杂交和基因渐渗的发生率，靛蓝鸟系统是迅速进化多样化和适应性进化的一个显著例子，代表了可以对进化过程进行研究的不寻常情况之一。这项研究将有助于重新引起进化生物学家对物种形成机制以及自然选择和性选择在产生生物多样性中的作用的兴趣。对靛蓝鸟种群的进化历史和遗传结构的清楚了解也将为未来分析口拟态的遗传和发育机制奠定基础，口拟态是这些宿主特异性育雏寄生虫的关键遗传适应。