Food concentration affects the life history response of Ceriodaphnia cf. dubia to chemicals with different mechanisms of action.
The effect of three chemicals with different mechanisms of action (3,4-dichloroaniline, fenoxycarb, and chlorpyrifos) on the life history response of the cladoceran Ceriodaphnia cf. dubia was examined under both limited (3 x 10(4) cells/mL) and abundant (15 x 10(4) cells/mL) food conditions. Toxicity tests were conducted at both food concentrations simultaneously for each chemical, and cladocerans were examined daily from less than 24 h old until their death. A range of life history parameters were calculated, including mean brood sizes, survival, net reproductive rate, and population growth rate. The toxicity of 3,4-dichloroaniline was not significantly affected by food concentration. However, limited food significantly decreased the toxicity of fenoxycarb, and significantly increased the toxicity of chlorpyrifos. The effect of food concentration on toxicity appears to depend on the mechanism by which the chemical exerts its toxicity and on food--chemical interactions. Possible mechanisms for the different effects of food concentration on toxicity are discussed.
Rose
R M
RM
Department of Environmental Sciences, University of Technology, Sydney, Australia. Rebecca.Rose@uts.edu.au
Warne
M St J
MS
Lim
R P
RP
D000814:Aniline Compounds / Q000633:toxicity*; D000818:Animals; D002219:Carbamates / Q000633:toxicity*; D004390:Chlorpyrifos / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects*; D005508:Food Deprivation; D018565:Food-Drug Interactions; D007306:Insecticides / Q000633:toxicity*; D019055:No-Observed-Adverse-Effect Level; D048448:Phenylcarbamates; D012098:Reproduction / Q000187:drug effects
D000814:Aniline Compounds; D002219:Carbamates; D007306:Insecticides; D048448:Phenylcarbamates; C014464:3,4-dichloroaniline; D004390:Chlorpyrifos; C052034:fenoxycarb