Department of Animal Ecology & Tropical Biology, University of Würzburg Biozentrum, Am Hubland, 97074 Würzburg, Germany.
Ann Bot. 2010 May;105(5):777-82. doi: 10.1093/aob/mcq045. Epub 2010 Mar 12.
Biological mutualisms rely on communication between partners, but also require protective measures against exploitation. Animal-pollinated flowers need to attract pollinators but also to avoid conflicts with antagonistic consumers. The view of flower visitors as mutualistic and antagonistic agents considers primarily the plants' interest. A classification emphasizing the consumer's point of view, however, may be more useful when considering animal's adaptations to flower visits which may include a tolerance against defensive floral scent compounds.
In a meta-analysis covering 18 studies on the responses of animals to floral scents, the animals were assigned to the categories of obligate and facultative flower visitors which considers their dependency on floral resources. Their responses on floral scents were compared.
On average, obligate flower visitors, often corresponding to pollinators, were attracted to floral scent compounds. In contrast, facultative and mainly antagonistic visitors were strongly repelled by floral scents. The findings confirm that floral scents have a dual function both as attractive and defensive cues.
Whether an animal depends on floral resources determines its response to these signals, suggesting that obligate flower visitors evolved a tolerance against primarily defensive compounds. Therefore, floral scent bouquets in conjunction with nutritious rewards may solve the conflicting tasks of attracting mutualists while repelling antagonists.
生物互惠关系依赖于合作伙伴之间的交流，但也需要采取保护措施来防止被剥削。传粉动物授粉的花朵既需要吸引传粉者，又需要避免与敌对的消费者发生冲突。将花访客视为互利和敌对的因素，主要考虑的是植物的利益。然而，从消费者的角度出发强调分类可能更有助于考虑动物对花访问的适应，这可能包括对防御性花香化合物的容忍度。
在一项涵盖 18 项关于动物对花香反应的研究的荟萃分析中，根据它们对花卉资源的依赖程度，将动物分为专性和兼性花访客两类。比较了它们对花香的反应。
平均而言，专性花访客，通常对应于传粉者，被花香化合物所吸引。相比之下，兼性和主要是敌对的访客则强烈排斥花香。研究结果证实，花香具有双重功能，既是有吸引力的，也是防御性的线索。
动物是否依赖花卉资源决定了它对这些信号的反应，这表明专性花访客进化出了对主要防御性化合物的耐受性。因此，花香与营养奖励相结合可能会解决吸引互利共生者同时排斥敌对者的矛盾任务。
