Extensive uses of various plant protection products may cause increasing concentrations of several nonsteroidal xenobiotics in surface water, among which RH5849 (1,2 -dibenzoyl-1-tert-butylhydrazine) is a well-known insect growth regulator that can induce a lethal premature moult in larval Lepidoptera. The purpose of this study was to assess the effects of 21% RH5849 wettable powder on life history traits of cladoceran zooplankton. The key species Daphnia magna, isolated from natural waters, was selected as the test organism. Results showed that survival time, first molting time, total molting times, clutches per female, offspring per clutch, and total offspring per female decreased significantly with increasing 21% RH5849 wettable powder concentration during the 21-day experiment, and the EC50 of the most sensitive parameter was 0.095 mg/L. The average time to first eggs and the time to first clutch were significantly delayed with increasing RH5849 wettable powder concentration, whereas the size of female at 21 d was significantly decreased with increasing 21% RH5849 wettable powder concentration. We conclude that 21% RH5849 wettable powder is toxic to D. magna as increased active ingredient resulted in decreased first molting time and total molting times, reduced growth, delayed average time to first eggs, lower reproduction, and, eventually, population decline. Keywords: Daphnia magna; Life history traits; insect growth regulator; RH5849; Reproduction

Effect of long-term exposure of a RH5849 formulation on the cladoceran <i>Daphnia magna</i>: Survival, moults, and reproduction

248th National Meeting (2014)

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Effect of long-term exposure of a RH5849 formulation on the cladoceran Daphnia magna: Survival, moults, and reproduction