Metallothionein in <italic>Hermetia illucens</italic> (Linnaeus, 1758) larvae (Diptera: Stratiomyidae), a potential biomarker for organic waste system.

Black soldier fly, <italic>Hermetia illucens</italic> (Linnaeus, 1758), is an important economic fly as its larvae can be used for recycling organic waste, such as food waste and manure. <italic>H. illucens</italic> larvae (BSFL) could uptake Cd from substrates and accumulate it inside bodies, which need to be monitored during waste treatment. Metallothionein (MT) usually serve as biomarker because of its role in metal homeostasis, detoxification, and dose response of heavy metals. Therefore, a MT gene was cloned from <italic>H. illucens</italic> (<italic>HIMT</italic>) that encoded 40 amino acids with typical cysteine rich features, which had a high sequence identity with other insect MTs. The expression of <italic>HIMT</italic> and total MT protein was measured in BSFL fed by meals spiked with gradient dose of Cd (0, 5, 50, 500 mg/kg) for 24, 48, 72, and 96 h, respectively. Dose-associated response of <italic>HIMT</italic> and total MT were found and the possible correlative range of Cd was from 5 to 50 mg/kg. The expression of <italic>HIMT</italic> might be a potential biomarker for monitoring Cd contamination by <italic>H. illucens</italic> in terrestrial organic matters, which might further apply in waste transformation system. [ABSTRACT FROM AUTHOR]