An apparent lack of prezygotic reproductive isolation among 42 sympatric species of Bromeliaceae in southeastern Brazil
An apparent lack of prezygotic reproductive isolation among 42 sympatric species of Bromeliaceae in southeastern Brazil
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巴西东南部 42 个同域凤梨科物种明显缺乏合子前生殖隔离
DOI：
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发表时间：
2008
影响因子：
1.9
通讯作者：
F. Guilherme
中科院分区：
文献类型：
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作者：
T. Wendt;T. S. Coser;G. Matallana;F. Guilherme
巴西东南部的大西洋雨林是凤梨科植物多样化的主要中心之一。对最近分化物种之间基因流动的不同合子前和合子后障碍的相对重要性的经验估计对于理解物种形成过程非常重要。虽然许多凤梨科植物物种在栽培中很容易杂交，但密切相关的同域物种之间自然杂交的记录很少表明存在强大的合子前障碍。 2004年至2005年对以9个属（Aechmea、Billbergia、Edmundoa、Neoregelia、Nidularium、Quesnelia、Racinaea、Tillandsia和Vriesea）为代表的42个同域凤梨科植物群落进行了调查，以评估微生境隔离、物候隔离和行为学隔离作为潜在的合子前障碍的作用。这些凤梨科植物在林下植物中含量丰富，并且经常密集地聚集在多特异性斑块中，这可能会促进混杂授粉。即使在同属物种之间，花期也有很大的重叠。大多数物种都有相似的访花群体。蜂鸟 Rhamphodon naevius 是 35 个物种的主要访客。仅观察到一种假定的杂交种。考虑到所研究的合子前隔离机制可能不足以有效避免种间授粉，这种杂交的不常见现象令人费解。
The Atlantic rainforest in southeastern Brazil is one the main centers of diversification of Bromeliaceae. Empirical estimates of the relative importance of different pre- and postzygotic barriers to gene flow between recently diverged species are important for understanding speciation processes. While many bromeliad species easily hybridize in cultivation, few records of natural hybrids between closely related sympatric species suggest the existence of strong prezygotic barriers. A community of 42 sympatric bromeliad species, represented by nine genera (Aechmea, Billbergia, Edmundoa, Neoregelia, Nidularium, Quesnelia, Racinaea, Tillandsia, and Vriesea), were surveyed from 2004–2005 to assess the role of microhabitat isolation, phenological isolation and ethological isolation as potential prezygotic barriers. These bromeliads are abundant in the understory and frequently grow densely aggregated in multispecific patches that may facilitate promiscuous pollination. There was a large overlap of flowering periods even between congeneric species. Most species shared a similar assemblage of flower visitors; the hummingbird Rhamphodon naevius was the major visitor for 35 species. Only one putative hybrid was observed. This uncommonness of hybridization is puzzling, given that the prezygotic isolation mechanisms investigated are potentially weak to effectively avoid interspecific pollination.