Bioaccumulation, bioamplification, and elimination behavior of per- and polyfluoroalkyl substances during insect metamorphosis: Different strategies for silkworms and locusts
By Nannan Wan, Yu Liu, Qiyu Wang, Shuai Liu, Miao Zhang, Mingqi Li, Xinghui Zhang, Xiandong Wang, and Bixian Mai
J Hazard Mater
October 22, 2025
DOI: 10.1016/j.jhazmat.2025.140209
Metamorphosis alters the concentration and composition of contaminants in insects; however, its effects on per- and polyfluoroalkyl substances (PFASs) are poorly understood. In this study, the bioaccumulation, bioamplification, and elimination behaviors of PFASs were compared between silkworms and locusts during metamorphosis (holometamorphosis vs paurometamorphosis). Perfluoroalkyl carboxylic acids and perfluoroheptane sulfonic acid (PFHpS) were the predominant PFASs in silkworm larvae, while PFHpS, perfluorooctane sulfonic acid (PFOS), and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) were dominated in locust larvae. The concentration and uptake efficiency of ΣPFASs in silkworm larvae were higher than those in locust larvae (p < 0.05), indicating that silkworm has a stronger bioaccumulation potential than locust. This is mainly due to locust larvae excrete high levels of PFASs (41-51 %) through their feces and therefore absorb fewer PFASs. The bioamplification factors of most PFASs in male and female silkworm were lower than the predicted values, and exuviation (mainly E2 and E3) is an important pathway for the elimination of PFASs during holometamorphosis. The higher elimination efficiencies of PFOS, 6:2 Cl-PFESA, and sodium p-perfluorous nonenoxybenzenesulfonate were observed in silkworms, but some short-chain PFASs shown higher elimination efficiencies in locusts. Overall, the elimination efficiencies of ΣPFASs in silkworms (34-39 %) were significantly higher than those in locusts (7.6-11 %, p < 0.05) during metamorphosis. These results suggest that silkworms and locusts exhibit different coping strategies in response to PFAS pollution, due to their distinct metamorphic processes and physiological functions. Furthermore, the cocoon formation by silkworms and the emergence of locusts were both delayed by one or two days after PFAS exposure. The sex-specific, dose-dependent, and long-term toxic effects of PFASs on insects require attention.
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