Abstract Feeding on sugar-rich resources dramatically prolongs lifespan and increases foraging performance in most parasitoids. The physiological and fitness effects of sugar feeding were studied in many parasitoid species under lab conditions, but far fewer studies examined them in the field. Even less is known about the environmental conditions that affect the prevalence of sugar feeding in natural parasitoid communities. Such information can guide planning of suitable habitats for these important biological control agents. We compared sugar feeding frequencies in parasitoid communities along four seasons, in wine-producing vineyards and in nearby natural plots, using qualitative anthrone tests. We also tested how the vineyards’ weed management practice (mechanical trimming or herbicide application) affected the parasitoids’ sugar feeding rates. Sugar feeding was significantly more common in the natural areas compared to the vineyards in all seasons. Sugar feeding rates were highest during spring and lowest in the winter. They were not consistently affected by weed management treatment, but increased with the number of flowering plant species, especially in spring. Our results suggest that parasitoids are limited by sugar sources in agricultural plots even when undisturbed by farming activities (during winter in our case), and that 'softer' weed management treatments do not necessarily improve their prospects for sugar feeding. A more targeted approach, of planting or preserving a higher richness of flowering plants throughout the seasons, may provide parasitoids with more sugar sources and thus support them in agricultural plots.

中文翻译：

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葡萄园内部和周围寄生蜂的糖食随季节和杂草管理实践而变化

摘要 以富含糖分的资源为食可显着延长大多数寄生蜂的寿命并提高觅食性能。在实验室条件下，在许多寄生蜂中研究了糖食对生理和健康的影响，但很少有研究在实地考察它们。对影响天然寄生物群落中食糖盛行的环境条件知之甚少。这些信息可以指导为这些重要的生物控制剂规划合适的栖息地。我们使用定性蒽酮测试比较了四个季节、产酒葡萄园和附近自然地块中寄生蜂群落的食糖频率。我们还测试了葡萄园的杂草管理实践（机械修剪或除草剂应用）如何影响寄生物的糖食率。与所有季节的葡萄园相比，在自然地区喂食糖分明显更为普遍。春季食糖率最高，冬季最低。它们并没有一直受到杂草管理处理的影响，但随着开花植物种类的增加而增加，尤其是在春季。我们的结果表明，即使在不受农业活动干扰的情况下（在我们的案例中是在冬季），寄生蜂也受到农业地块中糖源的限制，并且“较软”的杂草管理处理不一定会改善它们的糖食前景。一个更有针对性的方法，在整个季节种植或保存更丰富的开花植物，可以为寄生蜂提供更多的糖源，从而支持它们在农田中生长。