Lethal and sublethal toxic effects of a test chemical (ivermectin) on the yellow dung fly (Scathophaga stercoraria) based on a standardized international ring test.
A standardized bioassay using the yellow dung fly, Scathophaga stercoraria L. (Diptera: Scathophagidae), was developed to test the lethal and sublethal toxicity of parasiticide residues in livestock dung. The repeatability of the bioassay was assessed for the parasiticide ivermectin in 13 tests performed by seven laboratories in Germany, the United Kingdom, Switzerland, and Canada. Test results had an acceptable range of heterogeneity. The calculated median effective concentration for 50% (EC50) egg-to-adult mortality was 20.9 +/- 19.1 microg ivermectin/kg dung fresh weight (FW) (mean +/- standard deviation; range, 6.33-67.5 microg/kg). Mortality was not observed below a calculated no-observable-effect concentration (NOEC) of 8.1 +/- 7.7 microg/kg FW. However, prolonged development time (and, in a subset of tests, reduced body size) was observed above a calculated NOEC of 0.8 +/- 0.8 microg/kg FW. An oviposition site choice test revealed that yellow dung fly females do not discriminate among dung of different ivermectin concentrations. Thus, the yellow dung fly is suitably sensitive, and the methods are sufficiently repeatable, to support use of this standardized bioassay by the international community in the registration of new veterinary pharmaceuticals.
ECT Oekotoxikologie, Böttgerstr. 2-14, D-65439 Flörsheim, Germany. j-roembke@ect.de
Jörg
J
Römbke
Kevin D
KD
Floate
Ralf
R
Jochmann
Martin A
MA
Schäfer
Nalini
N
Puniamoorthy
Silvio
S
Knäbe
Jörn
J
Lehmhus
Boris
B
Rosenkranz
Adam
A
Scheffczyk
Thomas
T
Schmidt
Amanda
A
Sharples
Wolf U
WU
Blanckenhorn
D000818:Animals; D001681:Biological Assay / Q000592:standards*; D004175:Diptera / Q000187:drug effects*; D004784:Environmental Monitoring; D007559:Ivermectin / Q000592:standards* / Q000633:toxicity*; D018675:Toxicity Tests / Q000592:standards*
D007559:Ivermectin