School of Biological Sciences, Monash University, Melbourne, Australia.
School of Media and Communication, RMIT University, Melbourne, Australia.
Ann Bot. 2019 Sep 24;124(2):221-232. doi: 10.1093/aob/mcz043.
Pollinator-mediated interactions between plant species may affect the composition of angiosperm communities. Floral colour signals should play a role in these interactions, but the role will arise from the visual perceptions and behavioural responses of multiple pollinators. Recent advances in the visual sciences can be used to inform our understanding of these perceptions and responses. We outline the application of appropriate visual principles to the analysis of the annual cycle of floral colour structure in two Australian herbaceous communities.
We used spectrographic measurements of petal reflectance to determine the location of flowers in a model of hymenopteran colour vision. These representations of colour perception were then translated to a behaviourally relevant metric of colour differences using empirically calibrated colour discrimination functions for four hymenopteran species. We then analysed the pattern of colour similarity in terms of this metric in samples of co-flowering plants over the course of a year. We used the same method to analyse the annual pattern of phylogenetic relatedness of co-flowering plants in order to compare colour structure and phylogenetic structure.
Co-flowering communities at any given date seldom had colour assemblages significantly different from random. Non-random structure, both dispersion and clustering, occurred occasionally, but depended on which bee observer is considered. The degree of colour similarity was unrelated to phylogenetic similarity within a co-flowering community.
Perceived floral colour structure varied with the sensory capabilities of the observer. The lack of colour structure at most sample dates, particularly the rarity of strong dispersion, suggests that plants do not use chromatic signals primarily to enable bees to discriminate between co-flowering species. It is more likely that colours make plants detectable in a complex landscape.
植物种间的传粉媒介相互作用可能会影响被子植物群落的组成。花的颜色信号应该在这些相互作用中发挥作用，但这种作用将来自于多种传粉媒介的视觉感知和行为反应。视觉科学的最新进展可以为我们理解这些感知和反应提供信息。我们概述了将适当的视觉原理应用于分析澳大利亚两个草本植物群落中花的颜色结构年周期的方法。
我们使用花瓣反射率的光谱测量来确定膜翅目昆虫颜色视觉模型中花的位置。然后，我们使用四个膜翅目物种经验校准的颜色辨别函数将这些颜色感知表示转换为行为相关的颜色差异度量。然后，我们根据该度量在一年中共同开花植物的样本中分析颜色相似性的模式。我们使用相同的方法分析共同开花植物的年系统发育相关性模式，以比较颜色结构和系统发育结构。
在任何给定日期，共同开花的群落很少有明显不同于随机的颜色组合。非随机结构，包括分散和聚类，偶尔会发生，但取决于所考虑的蜜蜂观察者。颜色相似程度与共同开花群落内的系统发育相似性无关。
感知到的花色结构随观察者的感官能力而变化。在大多数样本日期缺乏颜色结构，特别是强烈分散的情况很少见，这表明植物主要不使用色觉信号来使蜜蜂能够区分共同开花的物种。更有可能的是，颜色使植物在复杂的景观中变得可见。
