Background Pollinating insects provide economically and ecologically valuable services, but are threatened by a variety of anthropogenic changes. The availability and quality of floral resources may be affected by anthropogenic land use. For example, flower-visiting insects in agroecosystems rely on weeds on field edges for foraging resources, but these weeds are often exposed to agrochemicals that may compromise the quality of their floral resources. Methods We conducted complementary field and greenhouse experiments to evaluate the: (1) effect of low concentrations of agrochemical exposure on nectar and pollen quality and (2) relationship between floral resource quality and insect visitation. We applied the same agrochemcial treatments (low concentrations of fertilizer, low concentrations of herbicide, a combination of both, and a control of just water) to seven plant species in the field and greenhouse. We collected data on floral visitation by insects in the field experiment for two field seasons and collected pollen and nectar from focal plants in the greenhouse to avoid interfering with insect visitation in the field. Results We found pollen amino acid concentrations were lower in plants exposed to low concentrations of herbicide, and pollen fatty acid concentrations were lower in plants exposed to low concentrations of fertilizer, while nectar amino acids were higher in plants exposed to low concentrations of either fertilizer or herbicide. Exposure to low fertilizer concentrations also increased the quantity of pollen and nectar produced per flower. The responses of plants exposed to the experimental treatments in the greenhouse helped explain insect visitation in the field study. The insect visitation rate correlated with nectar amino acids, pollen amino acids, and pollen fatty acids. An interaction between pollen protein and floral display suggested pollen amino acid concentrations drove insect preference among plant species when floral display sizes were large. We show that floral resource quality is sensitive to agrochemical exposure and that flower-visiting insects are sensitive to variation in floral resource quality.

中文翻译：

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肥料和除草剂改变花蜜和花粉质量，从而影响传粉昆虫的花卉选择

背景授粉昆虫提供具有经济和生态价值的服务，但受到各种人为变化的威胁。花卉资源的可用性和质量可能会受到人类土地利用的影响。例如，农业生态系统中的访花昆虫依赖田边的杂草来获取觅食资源，但这些杂草经常接触农用化学品，这可能会损害其花卉资源的质量。方法我们进行了互补的田间和温室实验，以评估：（1）低浓度农用化学品暴露对花蜜和花粉质量的影响；（2）花卉资源质量与昆虫访问之间的关系。我们应用了相同的农业化学处理（低浓度的肥料，低浓度的除草剂，两者的组合，以及仅控制水）到田间和温室中的七种植物物种。我们在两个田间季节的田间实验中收集了昆虫访问花卉的数据，并从温室中的重点植物收集了花粉和花蜜，以避免干扰昆虫在田间的访问。结果我们发现，暴露于低浓度除草剂的植物花粉氨基酸浓度较低，暴露于低浓度肥料的植物花粉脂肪酸浓度较低，而暴露于低浓度肥料或低浓度肥料的植物花蜜氨基酸浓度较高。除草剂。接触低浓度肥料也增加了每朵花产生的花粉和花蜜的数量。植物在温室中接受实验处理后的反应有助于解释实地研究中昆虫的造访。昆虫访视率与花蜜氨基酸、花粉氨基酸和花粉脂肪酸相关。花粉蛋白和花展示之间的相互作用表明，当花展示尺寸较大时，花粉氨基酸浓度会驱动昆虫对植物物种的偏好。我们表明，花卉资源质量对农用化学品暴露敏感，而访花昆虫对花卉资源质量的变化敏感。花粉蛋白和花展示之间的相互作用表明，当花展示尺寸较大时，花粉氨基酸浓度会驱动昆虫对植物物种的偏好。我们表明，花卉资源质量对农用化学品暴露敏感，而访花昆虫对花卉资源质量的变化敏感。花粉蛋白和花展示之间的相互作用表明，当花展示尺寸较大时，花粉氨基酸浓度会驱动昆虫对植物物种的偏好。我们表明，花卉资源质量对农用化学品暴露敏感，而访花昆虫对花卉资源质量的变化敏感。