Experiments were performed on compressed soil in the same way as described previously, but this time only one Collembola (10–12 days old) was introduced per Petri dish. Concentrations of dinoseb tested were 15, 20, 25 and View the MathML source dry soil. Each concentration and each control (with and without acetone) was replicated seven times. The test containers were maintained in the same conditions as the culture. Each week, the Petri dishes were aerated, one drop of bi-distilled water was added with a Pasteur pipette and one small stick of yeast View the MathML source was added. After each oviposition, Collembola were moved to a new Petri dish containing substrate contaminated on day 0 as the other dishes and kept under the same conditions. This enabled us to follow the same individual during the entire experiment.
Every 2–3 days, each Petri dish was put under a binocular microscope to determine the length of the organisms (head to abdomen), which was measured using an optical ocular with a built-in micrometer. The calculated precision was View the MathML source. However, as the Collembola can be flattened or some of their segments can be telescoped, the estimated measuring accuracy is undoubtedly closer to 0.05 mm.