Research Product

The influence of methoprene, a juvenile hormone analogue used in mosquito control, on survival, growth, and reproduction of the estuarine mysid, Mysidopsis bahia, was examined during exposure through a complete life in the laboratory. Total lethality occurred among all juvenile mysids exposed to 125 m g methoprene/l for 4 days. Mysids reared at a sublethal concentration (62 m g/l) weighed significantly less than unexposed mysids as they matured after 15 days of exposure. Release of the first brood was significantly delayed by as much as 3 days in mysids exposed to low mg/l concentrations of methoprene. The total number of young produced by groups of mysids during their first brood was insignificantly reduced when mysids were reared in methoprene concentrations greater than or equal to 8 mg/l. The most sensitive response of mysids to methoprene exposure was a significant reduction in number of young produced per female in concentrations > or = 2 mg/l. Ecological concern exists because the responses of mysids in this study to very low concentrations of a synthetic pesticide resemble responses of insects to juvenile hormone and juvenile hormone analogues. Similarity in these responses suggest that methoprene may be interfering with an endogenous endocrine system in this crustacean which utilizes juvenile hormone-like compounds.