Weak correlation of flower color and nectar-tube depth in temperate grasslands
Weak correlation of flower color and nectar-tube depth in temperate grasslands
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DOI：
10.1093/jpe/rtw029
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发表时间：
2017-04-01
影响因子：
2.7
通讯作者：
Martin Schaefer, H.
中科院分区：
文献类型：
--
作者：
Binkenstein, Julia;Stang, Martina;Martin Schaefer, H.
花蜜是植物提供给传粉者的最常见的花卉奖励之一。根据植物的种类，花蜜是公开提供的，或者是在不同长度的管子中提供的，这限制了短口器的访花者对这种资源的可及性。如果吸引与花形态相匹配的传粉者可以提高传粉效率，花可以从向传粉者发出蜜腺管深度信号中获益。由于花的颜色是重要的信号，在植物传粉通信，我们调查是否和不同的彩色或非彩色方面的花的颜色可能表明花蜜管深度或是否花的颜色促进花与长花蜜管之间的分化，通过高色度unifies.MethodsTo为此，我们收集了花的反射光谱的135个草原植物物种。我们分析了花的颜色作为原始的反射光谱的主成分分析（PCA）和颜色空间的蜜蜂。重要的发现花的颜色和管深度之间的相关性是弱的。从蜜蜂的角度来看，蓝色的花平均比绿色，蓝-绿色和紫外线-绿色花更深的管可能允许昆虫预测管深度的基础上蓝色。光谱纯度与蜜腺管的深度，也没有在蜜蜂的颜色空间的花颜色的色彩独特性。主波长显示出显着的，但很弱的相关性与管深度。无色绿色对比度随着管深度的增加而降低，亮度也是如此;因此深管比浅管不那么明显。PCA产生的色彩分量与管深度没有或仅略有相关。我们的研究结果表明，花的颜色可能有一定的潜力，以表明管的深度，即花蜜的可及性，从蜜蜂的角度来看。
AimsNectar is one of the most common floral rewards offered to pollinators by plants. Depending on the plant species, nectar is offered openly or in tubes of various lengths restricting accessibility of this resource for flower visitors with short mouthparts. If attracting pollinators that match floral morphology increases pollination efficiency, flowers could profit from signaling nectar-tube depth to pollinators. Since flower colors are important signals in plant-pollinator communication, we investigated whether and which different chromatic or achromatic aspects of flower color might indicate nectar-tube depth or whether flower colors facilitate the differentiation between flowers with long nectar tubes by means of high chromatic uniqueness.MethodsTo this end, we collected flower reflectance spectra of 135 grassland plant species. We analyzed flower colors as raw reflectance spectra in principal component analysis (PCA) and in the color space of honeybees.Important FindingsThe correlation between flower colors and tube depths was weak. From the bee's point of view, blue flowers had on average deeper tubes than green, blue-green and UV-green flowers potentially allowing insects to predict tube depths based on blue color. Spectral purity did not correlate with nectar-tube depth, nor did the chromatic uniqueness of flower colors in the honeybee color space. Dominant wavelength showed a significant but very weak correlation with tube depth. The achromatic green contrast decreased with increasing tube depth as did brightness; thus deep tubes were less conspicuous than shallow tubes. Chromatic components resulting from PCA did not or only slightly correlate with tube depth. Our results illustrate that flower colors may have a certain potential to indicate tube depth, i.e. nectar accessibility, from a bee's perspective.