The effects of a juvenile hormone analog (Altosid ZR-515) on the reproduction and development of<i>Daphnia magna</i>(Crustacea: Cladocera)

Abstract

Abstract Eleven concentrations of a juvenile hormone analog (Altosid), ranging from 3.2× 10−5 M to 3.2×1010 M, were tested on Daphnia magna. At the highest concentrations (3.2×10−5 M) this compound was lethal and at slightly lower concentrations (3.2×10−6 M) it inhibited reproduction among the survivors. At lower concentrations (1.6×10−6 M) adult survival was somewhat affected, and the production of embryos and the early stages of embryonic development were most sensitive. Embryogenesis was never completed and treated embryos did not develop further than the early stages. When very early- and early-stage embryos were treated, they did not develop into viable juveniles; those treated at the middle and late stages were able to develop. At still lower concentrations of Altosid (3.2×107 M), only the juveniles and early development were affected. At the lowest concentrations (3.2×108 M to 3.2×1010 M), Altosid appeared to have no effect on D. magna. Thus Daphnia, at early stages of development and in reproduction, are sensitive to concentrations of the juvenile hormone analog (JHA) similar to those which affect insect development. Keywords: Daphnia magna (Crustacea: Cladocera)reproductionembryogenesisAltosid (ZR-515)MethopreneJHJH analog