Are deception-pollinated species more variable than those offering a reward?
Are deception-pollinated species more variable than those offering a reward?
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DOI：
10.1007/s00606-011-0430-6
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发表时间：
2011-05-01
影响因子：
1.9
通讯作者：
Hof, David
中科院分区：
文献类型：
--
作者：
Ackerman, James D.;Cuevas, Ana A.;Hof, David
在大多数授粉系统中，动物在特定物种的植物之间传递花粉。传粉者的造访不是没有代价的，所以植物通常会提供奖励。然而，一些植物物种的花，主要是兰花，缺乏奖励，欺骗动物参观它们的花。欺骗性物种被认为在与广告和传粉者吸引相关的特征上具有高度的变异，这被归因于遗传漂移或传粉者行为造成的破坏性选择。由于稳定的选择，假定有奖励的物种具有较小的变异。我们比较了欺骗性物种和奖励物种在花形态和香味成分上的差异。因为这两组性状通常与花卉广告和传粉者吸引联系在一起，我们预计具有欺骗性授粉系统的物种的差异会比提供奖励的物种的差异更大。我们获得了在波多黎各、委内瑞拉和厄瓜多尔原生或归化的20个欺骗性物种和41个奖励物种的花形态指标。从8个欺骗性树种和4个奖励树种中采集了花香。我们发现，花形态和香气成分的变化幅度显著不同。形态变异系数的比较表明，总体上，欺骗性物种表现出显著高于奖励物种的变异，这种模式也在仅有兰花或仅在非兰花中发现。在一个功能授粉群中，兰花和非兰花之间的形态变异没有统计学差异。用贾卡德距离衡量，欺骗性树种的香气变化往往大于奖励树种。尽管两组之间的差异测量存在重叠，但数据支持这样一种假设，即在与传粉者吸引相关的特征上，欺骗授粉物种的种群比奖励物种的种群更具多样性。
In most pollination systems, animals transfer pollen among plants of a given species. Pollinator visitations do not come without cost, so plants usually offer a reward. However, the flowers of some plant species, mostly orchids, lack rewards and deceive animals into visiting their flowers. Deceptive species are thought to have high levels of variation in traits associated with advertisement and pollinator attraction, which have been attributed to genetic drift, or disruptive selection due to pollinator behavior. Rewarding species are assumed to have less variation due to stabilizing selection. We compared variability in floral morphology and fragrance composition between deceptive and rewarding species. Because both suites of traits are often linked with floral advertisement and pollinator attraction, we expected variation to be greater in species with deceptive pollination systems than in those offering rewards. We obtained floral morphology metrics for 20 deceptive species and 41 rewarding species native or naturalized in Puerto Rico, Venezuela, and Ecuador. Floral fragrances were sampled from eight deceptive species and four rewarding species. We found that the amplitude of variation in floral morphology and fragrance composition covaries significantly. Comparison of coefficients of variation for morphology indicated that, overall, deceptive species show significantly higher variation than rewarding species, and this pattern was also found among just orchids or just nonorchids. There were no statistical differences in morphological variation between orchids and nonorchids within a functional pollination group. Fragrance variation, measured by Jaccard distance, tended to be greater for deceptive species than for rewarding species. Although overlap in measures of variation occurs between the two groups, the data support the hypothesis that populations of deception-pollinated species are more variable than rewarding species in traits associated with pollinator attraction.