1. The hazard pesticides pose to pollinators are well-understood from laboratory studies. However, the field-level response of pollinators to pesticide use in agroecosystems is not well-established, nor is it clear if synergisms between pesticides affect pollinator visitation to crops.
2. Here, we evaluated if fungicide and insecticide use posed a hazard to wild and honeybees at 87 cucurbit—pumpkin, cucumber, watermelon—farms in the Midwestern United States. We also evaluated if synergisms between local- (i.e. focal cucurbit field) and landscape-level (i.e. surrounding crops) pesticide use influence wild and honeybee visitation to crop flowers.
3. We found that bees were exposed to pesticides above regulatory levels of concern and that synergisms between a few local insecticides and landscape-level fungicides reduced wild bee visitation to cucurbit flowers. Honey and bumblebee visitation to crops was not strongly influenced by synergisms between pesticides used at the local and landscape level.
4. Synthesis and applications. We found pesticides posed hazards to honey and wild bee species. However, pesticides were less likely to affect short-term visitation rates of honeybees compared with wild bee species. Thus, there is a need for changes in pesticide use at large spatial scales to reduce reliance on honeybees and maximize wild bee visitation to pollinator-dependent crops. We suggest that a multifaceted approach, involving collaborations between farmers, consumers and policymakers, will be fruitful to promote changes in pesticide use and wild bee pollinators.

中文翻译：

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当地和景观级农药之间的协同作用减少了依赖传粉媒介的作物中野生蜜蜂花卉的访问

1. 实验室研究已充分了解农药对传粉媒介的危害。然而，授粉媒介对农业生态系统中农药使用的田间反应尚未确定，也不清楚农药之间的协同作用是否会影响授粉媒介对作物的访问。
2. 在这里，我们评估了杀菌剂和杀虫剂的使用是否对美国中西部 87 个葫芦（南瓜、黄瓜、西瓜）农场的野生蜜蜂和蜜蜂构成危害。我们还评估了当地（即重点葫芦田）和景观水平（即周围作物）农药使用之间的协同作用是否会影响野生和蜜蜂对作物花卉的访问。
3. 我们发现蜜蜂暴露于高于监管水平的杀虫剂，并且一些当地杀虫剂和景观级杀菌剂之间的协同作用减少了野生蜜蜂对葫芦科花卉的访问。蜂蜜和大黄蜂对作物的访问不受当地和景观水平使用的杀虫剂之间的协同作用的强烈影响。
4. 合成与应用。我们发现杀虫剂对蜂蜜和野生蜜蜂物种构成危害。然而，与野生蜜蜂物种相比，杀虫剂不太可能影响蜜蜂的短期访问率。因此，需要在大空间范围内改变农药的使用，以减少对蜜蜂的依赖，并最大限度地增加野生蜜蜂对依赖传粉媒介的作物的访问。我们建议采取多方面的方法，包括农民、消费者和政策制定者之间的合作，将有助于促进农药使用和野生蜜蜂授粉媒介的改变。