Alterations Induced by Nano-Polystyrene Administration in Biological Parameters of Host-Endoparasitoids (Galleria mellonella and Pimpla turionellae) and Host Hemocyte Counts

Plastic pollution is one of the biggest threats to the environment and human health. Micro and nanoplastics are encountered in many areas of our daily lives and may accumulate in organisms, causing reduced life span, genotoxicity, and altered metabolism. Plastic pollution around the environment may lead to reductions in insect biodiversity and populations. It may also lead to the collapse of food webs and ecosystems of organisms that feed on them in the food chain. Therefore, the effects of nano-polystyrene (PSs) on the life cycle, biological characteristics, total hemocyte count (THCs) of the host, and hemocyte types of the model organism Galleria mellonella and its endoparasitoid Pimpla turionellae were investigated. Nano-PSs were produced according to the single emulsion solvent evaporation method and larval feeds were prepared with solutions of different concentrations. These diets were given to the larvae until they developed. The developmental time of the host-larvae fed with nano-PS-containing diets and the parasitoids that emerged using the pupae of these larvae as hosts were shortened. While the host adult weight and size increased, the weight of the parasitoid decreased. Dose-dependent decreases in THCs were observed. Prohemocyte, plasmatocyte, oenocytoid, and spherulocyte counts decreased, while granulocyte counts increased. Furthermore, the changes in the biology of the host exposed to nano-PSs indirectly affected the endoparasitoids. In addition, this study emphasizes that nanoplastic toxicity in honey-bees is generally ignored and that the consumption of bee products may pose potential hazards to human health. This reveals the crucial role of taking necessary precautions in beekeeping.