Data from: Attracting mutualists and antagonists: plant trait variation explains the distribution of specialist floral herbivores and pollinators on crops and wild gourds

PREMISE OF THE STUDY: Floral traits play important roles in pollinator attraction and defense against floral herbivory. However, plants may experience trade-offs between conspicuousness to pollinators and herbivore attraction. Comparative studies provide an excellent framework to examine the role of multiple traits shaping mutualist and antagonist interactions. METHODS: To assess whether putative defensive and attractive traits predict species interactions, we grew 20 different Cucurbitaceae species and varieties in the field to measure interactions with pollinators and herbivores and in the greenhouse to assess trait variation. Cucurbits are characterized by the production of cucurbitacins, bitter nonvolatile terpenoids that are effective against generalist herbivores but can attract specialist beetles. We determined whether plant traits such as cucurbitacins predict herbivore resistance and pollinator attraction using an information-theoretic approach. KEY RESULTS: Mutualists and floral antagonists were attracted to the same cucurbit varieties once they flowered. However, rather than cucurbitacin concentration, we found that the size of the flower and volatile emissions of floral sesquiterpenoids explained both pollinator and floral herbivore visitation preference across cucurbit taxa. This pattern held across cucurbit taxa and within the Cucurbita genus. CONCLUSIONS: Surprisingly, floral sesquiterpenoid volatiles, which are associated with direct defense, indirect defense, and attraction, rather than defense traits such as cucurbitacins, appeared to drive interactions with both pollinators and floral herbivores across cucurbit taxa. Identifying the relevant plant traits for attraction and deterrence is important in this economically valuable crop, particularly if pollinators and floral herbivores use the same plant traits as cues.研究前提（PREMISE OF THE STUDY）： 花部性状在吸引传粉者以及抵御花部植食性取食方面发挥着关键作用。然而，植物往往面临权衡取舍：既要提升自身对传粉者的可见性，又要避免过度吸引植食性昆虫。比较研究为解析多种性状如何调控互利共生与拮抗互作关系提供了极佳的研究框架。 研究方法（METHODS）： 为验证假定的防御性状与吸引性状能否预测物种间互作关系，本研究于田间种植了20个不同的葫芦科（Cucurbitaceae）物种与品种，以测定其与传粉者及植食性昆虫的互作情况；同时于温室中开展种植实验以评估性状变异。葫芦科植物以合成葫芦素（cucurbitacins）为典型特征：这类具有苦味的非挥发性萜类化合物可有效抵御广食性植食昆虫，但同时会吸引专食性甲虫。本研究采用信息论方法，旨在解析葫芦素等植物性状能否预测植株的植食抗性与传粉者吸引能力。 主要结果（KEY RESULTS）： 开花后，互利共生者（传粉者）与花部拮抗者（植食性昆虫）会被同一批葫芦科品种所吸引。但研究发现，在葫芦科类群中，解释传粉者与花部植食昆虫访花偏好的并非葫芦素浓度，而是花部大小与花部倍半萜类挥发物（floral sesquiterpenoids）的释放量。该规律在整个葫芦科类群以及南瓜属（Cucurbita）内均成立。 研究结论（CONCLUSIONS）： 令人意外的是，兼具直接防御、间接防御与吸引功能的花部倍半萜类挥发物，而非葫芦素这类防御性状，似乎主导了整个葫芦科类群中植物与传粉者及花部植食昆虫的互作关系。针对这类经济价值极高的作物，明确其用于吸引与驱避的关键植物性状具有重要意义，尤其当传粉者与花部植食昆虫以相同的植物性状作为定位线索时更是如此。