Microplastics in terrestrial insects, long-horned beetles (Coleoptera: Cerambycidae), from China

Despite studies have proposed that microplastics (MPs) could exert adverse effects on terrestrial ecosystems and biota, the occurrence of MPs in wild terrestrial insects has been rarely investigated. This study examined MPs in 261 long-horned beetle (Coleoptera: Cerambycidae) samples collected from four different Chinese cities. Detection frequency of MPs in long-horned beetles from different cities was 68-88 %. Long-horned beetles from Hangzhou (4.0 items/individual) had the highest mean abundance of MPs, followed by that from Wuhan (2.9 items/individual), Kunming (2.5 items/individual), and Chengdu (2.3 items/individual). The mean size of MPs in long-horned beetles from four Chinese cities was 381-690 μm. Fiber consistently represented the major shape of MPs in long-horned beetles from different Chinese cities, contributing 60, 54, 50, and 49 % of total items of MPs in Kunming, Chengdu, Hangzhou, and Wuhan, respectively. Polypropylene was the major polymer composition of MPs in long-horned beetles from Chengdu (68 % of total items of MPs) and Kunming (40 %). However, polyethylene and polyester were the major types of polymer compositions of MPs in long-horned beetles from Wuhan (39 % of total MP items) and Hangzhou (56 %), respectively. To our knowledge, this is the first study investigating the occurrence of MPs in wild terrestrial insects. These data are important for evaluating the risks of exposure to MPs for long-horned beetles.