Sex-Specific Bioamplification of Halogenated Organic Pollutants during Silkworm (Bombyx mori) Metamorphosis and Their Adverse Effects on Silkworm Development

Abstract

A partial life cycle test was performed with silkworms (Bombyx mori) exposed to different levels of halogenated organic pollutants (HOPs). The aims were to investigate the fate of HOPs during metamorphosis and the adverse effects of HOP exposures on silkworm development. Contaminant exposures resulted in decreased body weights, increased development times, and reductions of fecundity in silkworms. Assimilation efficiencies of HOPs decreased with an increasing octanol-water partition coefficient (log K-OW). From the larvae to the pupae stage, bioamplification factors (BAmFs) exhibited concentration-dependent results, in which there was a positive correlation with the log K-OW at the high concentrations but no correlation at the low concentrations. From the pupae to the moth stage, BAmFs were linearly negatively correlated with the log K-OW for males, but a parabolic correlation with the log K-OW was more suitable for females. Regarding reproductive activities, female moths selectively transferred low log K-OW HOPs to eggs by the oviposition except for highly halogenated lipophilic pollutants. However, BAmFs of male moths during mating showed no correlation with the log K-OW, although highly halogenated lipophilic pollutants had the highest BAmF values. The sex-specific bioamplification processes and special behaviors of highly halogenated lipophilic pollutants deserve further research.