Gegear Robert J, Manson Jessamyn S, Thomson James D
Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada.
Ecol Lett. 2007 May;10(5):375-82. doi: 10.1111/j.1461-0248.2007.01027.x.
Secondary compounds may benefit plants by deterring herbivores, but the presence of these defensive chemicals in floral nectar may also deter beneficial pollinators. This trade-off between sexual reproduction and defense has received minimal study. We determined whether the pollinator-deterring effects of a nectar alkaloid found in the perennial vine Gelsemium sempervirens depend on ecological context (i.e. the availability of alternative nectar sources) by monitoring the behavioural response of captive bumblebees (Bombus impatiens, an important pollinator of G. sempervirens in nature) to nectar alkaloids in several ecologically relevant scenarios. Although alkaloids in floral nectar tended to deter visitation by bumblebees, the magnitude of that effect depended greatly on the availability and nectar properties of alternative flowers. Ecological context should thus be considered when assessing ecological costs of plant defense in terms of pollination services. We consider adaptive strategies that would enable plants to minimize pollinator deterrence because of defensive compounds in flowers.
次生化合物或许可通过驱赶食草动物而使植物受益，但花蜜中这些防御性化学物质的存在也可能会驱赶有益的传粉者。这种在有性繁殖与防御之间的权衡很少得到研究。我们通过监测圈养的熊蜂（熊蜂属，自然界中常绿钩吻的重要传粉者）在几种与生态相关的情景下对花蜜生物碱的行为反应，来确定在多年生藤本植物常绿钩吻中发现的一种花蜜生物碱对传粉者的驱赶作用是否取决于生态背景（即替代花蜜来源的可获得性）。尽管花蜜中的生物碱往往会阻止熊蜂来访，但这种影响的程度在很大程度上取决于替代花朵的可获得性和花蜜特性。因此，在根据传粉服务评估植物防御的生态成本时，应考虑生态背景。我们考虑了一些适应性策略，这些策略能使植物将花朵中防御性化合物对传粉者的驱赶作用降至最低。
