Joint effects of cadmium and copper on Apis mellifera forgers and larvae

• Published in: Comparative biochemistry and physiology. Toxicology & pharmacology Vol. 237; p. 108839
• Main Authors: Di, Ning, Zhang, Kai, Hladun, Kristen R., Rust, Michael, Chen, Ya-Feng, Zhu, Zheng-Yang, Liu, Tong-Xian, Trumble, John T.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-11-2020
• Subjects: Animals; Bees - drug effects; Bees - physiology; Body burden; Cadmium - toxicity; Copper - toxicity; Drug Combinations; Drug Synergism; Feeding Behavior - drug effects; Heavy Metal Poisoning - etiology; Heavy Metal Poisoning - pathology; Heavy metals; Larva - drug effects; Pollinators; Sucrose - metabolism; Sucrose response threshold; Synergism; Toxicity Tests, Acute; Body burden; Synergism; Sucrose response threshold; Heavy metals; Pollinators
• ISSN: 1532-0456; 1878-1659
• DOI: 10.1016/j.cbpc.2020.108839

Honey bees (Apis mellifera L.) are important ecological and agricultural resources. They are among the most widely available pollinators and provide products as well as services. Unfortunately, honey bee populations are susceptible to several environmental threats, including heavy metal exposure. Honey bees can be exposed to heavy metals when foraging on contaminated honey and pollen resources, and in some cases by airborne exposure. We studied the joint acute and chronic effects of cadmium (Cd) and copper (Cu) on A. mellifera. A 1:1 solution of the two heavy metals increased larval developmental duration and the mortality of both larvae and foragers in a dose-dependent way, decreased forager feeding, increased body metal burdens, and disrupted the sucrose response behavior of foragers. In combination, Cd and Cu demonstrated a weakly synergistic effect on foragers, but for larvae an initially antagonistic effect at low doses changed to strongly synergistic response at higher concentrations. The sucrose response threshold of foragers decreased significantly when they were dosed with increasing concentrations of the metal mixtures. Overall, the fitness of honey bee larvae and foragers is detrimentally affected when these metals co-occur.
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•Honey bees are exposed to heavy metals, but metals are rarely tested in combination.•Copper and cadmium have a dose dependent effect on forager mortality and behavior.•Toxicity based on adult exposure greatly underestimates effects on larvae.•For larvae, the joint effects became synergistic with increasing concentrations.•Honey bee fitness is strongly and negatively affected when these metals co-occur.