Department of Biology, University of Washington, Seattle, WA 98195, USA.
Integr Comp Biol. 2011 Nov;51(5):781-93. doi: 10.1093/icb/icr094. Epub 2011 Jul 29.
Plants and their pollinators are excellent examples of mutualistic associations that range in specialization, from obligate to generalized mutualisms, with many pollinators interacting with diverse species of flowers while still maintaining specialized associations. Although floral odors have been implicated in mediating these interactions, identification of the odors-and how the odors are represented in the olfactory system-has been elusive, and the manner in which olfactory learning mediates the generalized plant-insect interactions in the field remains unclear. This review details the composition of floral bouquets that elicit strong attraction in pollinators, demonstrating that for some species of plants the composition of the bouquet plays an important role in exploiting the insect's olfactory system, thereby driving innate attraction, whereas other bouquets can be learned as an associative cue for the nectar reward. By associative learning of nonattractive floral odors with a nectar reward-through octopamine-associated modulation of neurons in the antennal lobe-insects have the ability to exploit alternate floral resources when their preferred flowers are no longer present. Such neural mechanisms, present in specialist and generalist pollinators, provides the means by which pollination associations can range from specialized to generalized while permitting insects to exist within a dynamic floral environment.
植物及其传粉者是互利共生关系的绝佳范例，这种关系的专化程度从专性到广义互利共生不等，许多传粉者与不同种类的花相互作用，同时仍然保持着专门的联系。虽然花香被认为介导了这些相互作用，但气味的识别以及气味在嗅觉系统中的表现方式一直难以捉摸，嗅觉学习在多大程度上介导了田间广义的植物-昆虫相互作用也不清楚。这篇综述详细介绍了那些能引起传粉者强烈吸引力的花束的组成，表明对于某些植物物种来说，花束的组成在利用昆虫的嗅觉系统方面起着重要作用，从而驱动先天吸引力，而其他花束则可以作为与花蜜奖励相关的联想线索来学习。通过与花蜜奖励相关的非吸引性花香的联想学习——通过触角叶中神经元的章鱼胺相关调制——昆虫能够在它们喜欢的花不再存在时利用替代的花资源。这种存在于专门和一般传粉者中的神经机制为传粉者的联系提供了从专门到广义的途径，同时允许昆虫在动态的花环境中生存。
