Fate of mercury accumulated by blowflies feeding on fish carcasses.

Because fish represent the principal methylmercury (MeHg) pool in the water column of freshwater systems, MeHg released from their carcasses could represent an important flux to the environment. Necrophagous invertebrates such as fly larvae can play an important role in this Hg recycling. We studied Hg accumulation by blowflies (Diptera, Calliphoridae) feeding on beached fish carcasses in the field. We found that the MeHg these flies accumulated as larvae is retained in their pupal stage but is eliminated by the adult following emergence. We conclude that calliphorids possess an efficient mechanism for excreting the MeHg that they accumulate from carcasses.