Management practice for small hive beetle as a source of microplastic contamination in honey and honeybee colonies

Microplastics (MP) have emerged as a widespread environmental contaminant affecting bee health. In this study we report on the impact of one of the cultural practices used to control the small hive beetle (SBH, Aethina tumida). Management of the beetle often includes the use of in-hive traps of different kinds, such as non-woven microfiber wipes. When placed inside the hive, bees chew on these wipes, which then become fuzzy and fray to the point where beetles become entangled in their fibers. The current study aimed to examine the composition of these microfiber sheets and to evaluate whether their use resulted in unintended MP contamination of bees and honey. We treated hives with one blue microfiber sheet placed on top of the frames for at least three months. After that time, we collected adult bees and honey samples from treated hives, control hives in the same apiary (control near), and control hives in an apiary 7.5 km away (control far). Honey from treated hives had a significantly greater number of blue MF than honey from the control hives (mean ± SD, treatment 11.83 ± 3.76, control near 2.25 ± 0.92 and control far 0.25 ± 0.5 MF/20 gr honey). Also, hives treated with the microfiber sheets had a significantly greater number of blue microfibers in the gut and cuticle of bees, than the control hives located in a different apiary. However, the control and treated bees located in the same apiary had a similar number of blue microfibers (mean ± SD, treatment 4.7 ± 2.28, control near 3 ± 1.63 and control far 0.5 ± 0.58 MF in 20 bees). Thus, the current study raises concerns of the use of microfibers sheets to trap the SBH as it results in the incorporation of microfibers into the ecosystem and the food chain.