The role plant diversity has played in regulating insect communities has been of interest for decades. Recent syntheses from agroecosystems suggest increasing plant diversity can positively affect beneficial insects like predators, reducing pest pressure and increasing yield. However, the agricultural landscape of the Midwestern United States is dominated by just two crops—corn and soybean—which cover approximately 180 million acres of arable land yearly. New ideas to conserve wildlife that additionally provide economic opportunities for farmers must be developed in order to promote sustainable and resilient ecosystems. Here we tested the capacity of an alternative cropping system to support more diverse insect populations than conventional cropping systems. We quantified differences in the diversity of an insect taxon, ants (Hymenoptera: Formicidae), over an annual cycle using pitfall traps in thirty-two 2-m² plots of either woody perennial polycultures that contained apples, chestnuts, currants, hazelnuts, and raspberries or conventional corn-soybean rotations. In doing so, we found that woody perennial polycultures supported 2.4-fold more ant species and maintained a unique fauna of specialist and predatory ants. The observed differences in diversity were linked to higher levels of predation as 18.2-fold more sentinel prey were consumed during each month of the growing season. Combined, our results suggest that agricultural landscapes in the Midwestern United States can be modified to support important beneficial insects like ants while still producing commodities that can be economically beneficial to farmers.

几十年来，植物多样性在调节昆虫群落中所起的作用一直引起人们的兴趣。最近对农业生态系统的综合表明，增加植物多样性可以对捕食者等有益昆虫产生积极影响，减少害虫压力并提高产量。然而，美国中西部的农业景观主要由两种作物——玉米和大豆——每年覆盖约 1.8 亿英亩的耕地。为了促进可持续和有复原力的生态系统，必须开发新的保护野生动物的想法，从而为农民提供额外的经济机会。在这里，我们测试了替代种植系统支持比传统种植系统更多样化的昆虫种群的能力。我们量化了昆虫分类群蚂蚁（膜翅目：²块含有苹果、栗子、黑醋栗、榛子和覆盆子的多年生木本混种植物或常规玉米-大豆轮作的地块。在这样做的过程中，我们发现多年生木质混养支持的蚂蚁种类增加了 2.4 倍，并保持了独特的专业和捕食性蚂蚁动物群。观察到的多样性差异与更高水平的捕食有关，因为在生长季节的每个月消耗的哨兵猎物增加了 18.2 倍。综合起来，我们的研究结果表明，美国中西部的农业景观可以进行改造，以支持蚂蚁等重要的有益昆虫，同时仍然生产对农民经济有利的商品。