Table 2 Dose–effect relationship parameters and mean combination index (CI) values of chlorpyrifos (C), imidacloprid (I), and thiamethoxam (T) singly and in binary and ternary combinations in bumblebee tests after 48 h of exposure. The computer software CompuSyn was used to calculating the D_m, m, r, and CI values. The parameters D_m, m, and r are the antilog of the x-intercept, the slope, and the linear correlation coefficient of the median-effect plot, which indicate the potency (LD₅₀), the shape of the dose–effect curve, and the conformity of the data to the mass-action law, respectively^38,39,40. The D_m and m values were used to calculate the CI values (Eq. (4)), and CI < 1, CI > 1, and CI = 1 represent synergism, antagonism, and an additive effect, respectively. LD₁₀, LD₅₀, and LD₉₀ are the doses producing a 10%, 50%, and 90% mortality rate in bumblebees, respectively. Doses are in micrograms of active ingredient per bee.

From: Assessing the toxicological interaction effects of imidacloprid, thiamethoxam, and chlorpyrifos on Bombus terrestris based on the combination index