ARTHROPODS USED AS BIOINDICATORS OF MICROPLASTICS IN THE TERRESTRIAL EVIRONMENT: THE CASE OF CARABID BEETLES (COLEOPTRA, CARABIDAE)

Microplastics (MPs) are defined as plastic particles with a range size varying from 1µm to 5mm and with regular or irregular shapes. The widespread of MPs in various ecosystems including oceans, soils, and freshwater, makes organisms exposed to these emerging contaminants. MPs' bioavailability and toxicity impact the environment negatively. Therefore, it is essential to monitor the presence of MPs in different environments using a sustainable method as the employment of insects as biological control agents (bioindicators). Bioindicators refer to living organisms with specific characteristics that make them suitable to monitor the contaminants in different environments. In this research, carabidae beetles (Coleoptera: Carabidae), a predominantly terrestrial insect group, have been used for the first time as bioindicators: their biological and morphological characteristics and their widespread make them ideal for studying the impact of MPs on terrestrial environment. Samplings have been carried out by placing pitfall traps along the coastal of the Conero area, Ancona, Italy. The traps have been checked every two weeks from July to October 2022, and insects were sampled on seasonal bases. The caught specimens have been identified at the family level, counted, and dissected in order to obtain digestive tracts for the subsequent MPs extraction and characterization. The results indicated that carabidae beetles ingest MPs with a frequency ranging between 40 to 90% depending on the site and seasonal periods, mainly shaped on fragments, and sized between 0.1 1mm, while polyester and silicon are the main represented polymers. Considering the few information present in the literature and the need to identify good biological control agents, the results of this study could be useful for the future and applied in other environmental contexts. Besides Carabidae, identification and analysation of other arthropods present in traps will be considered a plus to have further information about the MPs presence.