Consistent shifts in pollinator-relevant floral coloration along Rocky Mountain elevation gradients
Consistent shifts in pollinator-relevant floral coloration along Rocky Mountain elevation gradients
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DOI：
10.1111/1365-2745.12948
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发表时间：
2018-09-01
影响因子：
5.5
通讯作者：
Whitney, Kenneth D.
中科院分区：
文献类型：
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作者：
Gray, Michelle;Stansberry, Marcus J.;Whitney, Kenneth D.
1. 花色是塑造植物与传粉者相互作用的基本信号。尽管有理论上的原因说明花的颜色可能会沿着生物和非生物梯度发生变化，但很少有研究检查群落水平的颜色变化，甚至检测到的显着模式也更少。2。我们检查了美国科罗拉多州落基山脉 6 个复制横断面（横跨 1,300 米）的花朵颜色。沿着这些横断面，随着海拔的增加，假设授粉从蜜蜂主导转向苍蝇主导。使用分光光度计测量了 110 种草本植物和灌木物种的花朵的反射率，并用于估计相关授粉媒介视觉空间中颜色的三个组成部分（色调、饱和度和亮度）。从 67 个地点收集了覆盖百分比数据，并用于获得花色的群落加权平均值 (cwm) 估计值。3．我们发现花色随海拔变化有明显的规律。较短波长（UVB 到人类蓝色，300-500 nm）的反射率 cwm 通常随海拔高度线性下降，而较长波长（人类绿色到红色，500-700 nm）的反射率 cwm 显示出驼峰形图案，在中间海拔处反射率最高。对于传粉媒介来说，蜜蜂和果蝇视觉空间的饱和度 cwm 都随着海拔的升高而显着增加，而蜜蜂空间的亮度对比度 cwm 则呈现驼峰状模式，而果蝇视觉空间的亮度对比度则随着海拔的升高而下降。就色调而言，蜂蓝色物种的覆盖范围随着海拔的升高而下降，而蜂紫外绿色物种的覆盖范围则呈现驼峰状模式。相比之下，我们没有检测到果蝇感知到的花卉色调的海拔变化。4。合成。色调模式与蜜蜂传粉媒介塑造了花色地理的假设是一致的。尽管高海拔地区花朵亮度的下降与低温和更强烈的紫外线辐射有利于色素浓度增加的预测相一致，但蝇类传粉媒介和非生物驱动因素的作用更难以推断。我们的研究结果表明，花色在整个景观中是动态且可预测的，这种模式为梳理这一重要植物性状的生态和进化驱动因素提供了机会。
1. Floral colour is a fundamental signal that shapes plant-pollinator interactions. Despite theoretical reasons why floral colours might shift in representation along biotic and abiotic gradients, few studies have examined community-level shifts in colour, and even fewer significant patterns have been detected.2. We examined floral colour on six replicated transects spanning 1,300 m in the Rocky Mountains of Colorado, USA. Along these transects, there is a hypothesized shift from bee-dominated to fly-dominated pollination with increasing elevation. The reflectance of flowers of 110 forb and shrub species was measured using a spectrophotometer, and was used to estimate three components of colour (hue, saturation and brightness) in relevant pollinator visual spaces. Percent cover data were collected from 67 sites and used to obtain community-weighted mean (cwm) estimates of floral colour.3. We found strong patterns of elevational change in floral colour. Reflectance cwm of shorter wavelengths (UVB through human blue, 300-500 nm) generally decreased linearly with elevation, while reflectance cwm of longer wavelengths (human green through red, 500-700 nm) showed hump-shaped patterns with highest reflectance at intermediate elevations. With respect to pollinators, saturation cwm increased significantly with elevation in both bee and fly visual spaces, while brightness contrast cwm showed a hump-shaped pattern in bee space and a decline with elevation in fly visual space. For hue, cover of species perceived as bee-blue declined with elevation, while cover of bee-UV-green species showed a hump-shaped pattern. In comparison, we detected no elevational shifts in floral hues as perceived by flies.4. Synthesis. Hue patterns are consistent with the hypothesis that bee pollinators have shaped the geography of floral colour. The roles of fly pollinators and of abiotic drivers are more difficult to infer, although the drop in floral brightness at high elevations is consistent with predictions that low temperatures and more intense ultraviolet radiation should favour increased pigment concentrations there. Our results indicate that floral colour can be dynamic yet predictable across the landscape, a pattern that provides opportunities to tease apart the ecological and evolutionary drivers of this important plant trait.