Improper Use of Copper‐Based Fungicides May Promote Population Growth in Bactrocera dorsalis

Heavy metal pollution has emerged as an urgent environmental and public health concern. Excessive heavy metals can be transmitted and accumulated in animals and plants along the food chain, thereby affecting the growth, development, and stability of the biological community. Copper (Cu)‐based fungicides are a class of plant protectants that usually persist in large quantities on plant surfaces, and there are even cases of abuse and overuse in some regions. Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is a quarantine pest with wide distribution and host range. This study evaluated the effects of varying concentrations of Cu 2+ derived from Cu‐based fungicides on the reproduction and insecticide tolerance of B. dorsalis . The results showed that ingestion of low‐concentration Cu 2+ (2 μg/g) prolonged the lifespan of adults and improved egg hatchability, enhancing the Vg/VgR expression, ovary development, and egg production. Conversely, when exposed to medium concentration (10 μg/g), these parameters declined significantly. Interestingly, under high concentrations of Cu 2+ (50 μg/g), the parameters rebounded to varying degrees. In addition, after excessive Cu 2+ intake, the tolerance of B. dorsalis to imidacloprid, clothianidin, and deltamethrin increased significantly. Collectively, our results proved that the improper use of Cu‐based fungicides may promote the population expansion of B. dorsalis and improve its tolerance to adverse environments such as insecticides.