背景:植物通常使用花卉展示来吸引相互主义者并防止拮抗剂攻击。从远处可检测到的化学展示物包括有吸引力的或有排斥性的花香挥发性有机化合物(FVOC)。本地,游客认为接触化学物质,包括营养素,但也有威慑或有毒成分的花粉和花蜜。FVOC和花粉化学组成可以在种内和种间变化。对于某些传粉者和花卉物种,在特定的植物系统中研究了对这些化合物的反应;但是我们缺乏比较这两组的一般模式的综合方法,也缺乏对FVOC与花粉化学多样性之间潜在相关性的见解。
方法:我们回顾了FVOCs和非挥发性花卉化学显示,即,花粉营养和毒素,成分不同,影响昆虫访客的检测和行为。此外,我们使用荟萃分析来评估传粉者对FVOCs的检测和反应同一植物属内的花卉。我们还测试了FVOCs的化学多样性,花粉营养素和毒素是相关的,因此是互为信息的。
结果:根据现有数据,花虫比传粉者能检测到更多的FVOCs。经常测试的FVOC通常被报道为吸引传粉者和驱虫植物。在两个访客群体测试的FVOC中,有更多的有吸引力的化合物比驱虫化合物。FVOC与花粉毒素丰富度呈负相关,表明权衡,同时观察到花粉蛋白量与毒素丰富度之间的边际正相关。
结论:植物面临关键的权衡,因为花卉化学物质向互助者和拮抗剂传递类似的信息,特别是通过吸引人,更少的驱虫剂,FVOCs。此外,花卉可能会检测到更多的FVOCs,其丰富度与奖励化学丰富度相关。FVOC化学多样性是奖励性状的潜在信息。为了更好地了解塑造花卉化学展示的生态过程,需要对不同植物物种的花卉拮抗剂进行更多的研究,以及花卉化学多样性对游客反应的作用。
Plants often use floral displays to attract mutualists and prevent antagonist attacks. Chemical displays detectable from a distance include attractive or repellent floral volatile organic compounds (FVOCs). Locally, visitors perceive contact chemicals including nutrients but also deterrent or toxic constituents of pollen and nectar. The FVOC and pollen chemical composition can vary intra- and interspecifically. For certain pollinator and florivore species, responses to these compounds are studied in specific plant systems, yet we lack a synthesis of general patterns comparing these two groups and insights into potential correlations between FVOC and pollen chemodiversity.
We reviewed how FVOCs and non-volatile floral chemical displays, i.e. pollen nutrients and toxins, vary in composition and affect the detection by and behaviour of insect visitors. Moreover, we used meta-analyses to evaluate the detection of and responses to FVOCs by pollinators vs. florivores within the same plant genera. We also tested whether the chemodiversity of FVOCs, pollen nutrients and toxins is correlated, hence mutually informative.
According to available data, florivores could detect more FVOCs than pollinators. Frequently tested FVOCs were often reported as pollinator-attractive and florivore-repellent. Among FVOCs tested on both visitor groups, there was a higher number of attractive than repellent compounds. FVOC and pollen toxin richness were negatively correlated, indicating trade-offs, whereas a marginal positive correlation between the amount of pollen protein and toxin richness was observed.
Plants face critical trade-offs, because floral chemicals mediate similar information to both mutualists and antagonists, particularly through attractive FVOCs, with fewer repellent FVOCs. Furthermore, florivores might detect more FVOCs, whose richness is correlated with the chemical richness of rewards. Chemodiversity of FVOCs is potentially informative of reward traits. To gain a better understanding of the ecological processes shaping floral chemical displays, more research is needed on floral antagonists of diverse plant species and on the role of floral chemodiversity in visitor responses.