Data from: Direct and indirect effects of urbanization, pesticides, and wild insect pollinators on mango yield

Expanding cities increasingly encroach fertile farmlands, questioning the viability of maintaining agriculture within and around them. Yet, our knowledge on how urbanization influences pollinator communities and the provision of pollination services to crops is limited, especially for the urbanization hotspots of the Global South. Mango (Mangifera indica) is one of the most important fruit crops in tropical countries. To analyze the dependency of mango on its main insect pollinators, and the direct and indirect effects of urbanization and insecticides on pollinator abundance and mango yield, we conducted a pollinator exclusion experiment and sampled flower visitors on 16 mango farms spread across rural-urban landscapes in Bengaluru, a South Indian megacity. We found that allowing flowers access to ants and flying visitors (bees, hoverflies, non-syrphid flies), dramatically increased mango yield by 350%, highlighting the importance of wild insects for mango pollination. We detected a trend between wild bee abundance and the final fruit set, with an increase of 20% when the number of bees increased from 25 to 125. Urbanization did not directly affect pollinator abundance or mango yield. However, the amount of insecticide applications had strong negative effects on wild bee abundance at low and intermediate levels of urbanization, while it had no effect in highly urbanized areas, presumably because of higher availability of flowering resources. Moreover, the amount of insecticides decreased the weight of harvested mango fruits by almost 30%. This may indicate trade-offs between conventional pest control and enhanced crop yields through pollination by wild insects in rural areas. Synthesis and applications. Our results indicate that mango production can be maintained at a profitable level in urbanized landscapes with insect pollinators more than tripling final yield. However, increasing use of insecticides, besides raising farmers' expenses, can have negative effects on wild insect pollinators and mango yield, especially in rural areas. To safeguard crucial pollination services, it is therefore critical to conserve and promote wild insect pollinators by minimizing the negative effects of insecticide applications in these areas.

不断扩张的城市正日益侵占肥沃农田，使得在城市内部及周边维持农业生产的可行性受到质疑。然而，我们对于城市化如何影响传粉者群落，以及其如何为作物提供传粉服务的认知仍较为有限，在全球南方（Global South）的城市化热点区域这一问题尤为突出。
芒果（Mangifera indica）是热带国家最重要的果树作物之一。为分析芒果对其主要昆虫传粉者的依赖关系，以及城市化与杀虫剂对传粉者丰度和芒果产量的直接、间接影响，我们在印度南部大都市班加罗尔（Bengaluru）范围内横跨城乡景观的16个芒果农场开展了传粉者排除实验，并对访花昆虫进行了采样。
研究发现，允许蚂蚁和飞行访花者（包括蜜蜂、食蚜蝇、非食蚜蝇类蝇类）接触花部，可使芒果产量大幅提升350%，凸显了野生昆虫对芒果传粉的重要性。我们观测到野生蜂类丰度与最终坐果率之间存在正相关趋势：当蜂群数量从25只增至125只时，坐果率可提升20%。
城市化并未直接影响传粉者丰度或芒果产量。但在低、中等城市化水平区域，杀虫剂施用强度对野生蜂类丰度存在显著负向影响；而在高度城市化区域则无此效应，推测原因是该类区域开花资源的可获得性更高。
此外，杀虫剂施用强度会使采收芒果的单果重量降低近30%。这一结果或表明，在农村地区，传统害虫防治与通过野生昆虫传粉提升作物产量之间存在权衡关系。
综合与应用。我们的研究结果显示，在存在昆虫传粉者的城市化景观中，芒果生产可维持在盈利水平，且最终产量可增至原产量的3倍以上。然而，杀虫剂使用量的增加不仅会提升农户的种植成本，还会对野生昆虫传粉者及芒果产量产生负面影响，在农村地区这一问题尤为突出。因此，为保障关键的传粉服务，在这些区域通过降低杀虫剂施用的负面影响来保护并促进野生昆虫传粉者，显得尤为关键。