Chronotoxicity of female <i>Drosophila suzukii</i> for acute contact exposure to insecticides.

<p>Normalized percent mortality (Y-axis) of female <i>D. suzkii</i> exposed to malathion (A,C) and fenpropathrin (B,D) for 1 h (±5min) was assessed at 4 time points (ZT0, 6, 12, 20) for flies entrained to conditions approximating Watsonville, CA, U.S.A. summer (July/August) temperature and light/dark conditions (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068472#pone-0068472-g001" target="_blank">Figure 1</a> and Table S1 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068472#pone.0068472.s001" target="_blank">File S1</a>) for approximately 50 h prior to exposure. The insecticide dose [expressed in Log(µmol of insecticide active ingredient (AI)/cm²) (X-axis)] was prepared from formulated insecticide using acetone as a solvent 1 h prior to the contact experiment and 250 µL was applied to coat the interior of a 20 mL scintillation vial (56.9 cm²). Flies were held in pesticide-free diet at Watsonville, CA summer conditions for 72 h (±5min) after exposure when mortality was assessed as a count of dead and moribund flies combined. Points on the graph represent the mean normalized percent mortality exhibited at each Log(Dose) for the female flies assayed (across the three replicate vials) (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068472#pone-0068472-t001" target="_blank">Table 1</a>). The points were separated along the x-axis using the “nudging” function in PRISM v.5.0 (GraphPad Software, Inc.) to prevent overlap of the standard error bars (i.e. the standard error of the mean of the normalized percent mortality across the three replicates) (A, B). The variable slope sigmoidal dose response best-fit curves produced in PRISM v.5.0 for malathion are graphed and similarly separated along the x-axis with the points (A), and the single best-fit curved produced for all time points for fenpropathrin was shifted toward the middle of the graph, again using the “nudging” function in PRISM v.5.0 (B). The points and curves are presented without their error bars and without shifting along the x-axis for dose response comparison of malathion (C) and fenpropathrin (D).