Comparison of simulation and quantitative experimental data. Orange bars indicate stimulation with attractant orange light, blue bars stimulation with repellent blue light, and green stimulation with attractant chemo-stimuli. The final model was fitted (see Methods) to quantitative experimental data from References  in (A), and  in (B). The output of the model is shown in red, experimental data in black. The same parameter values were used for all fittings, but only the parameter describing the experimental side conditions (see Methods and Additional file 1) were varied to account for different experimental conditions and strains. In the simulations, 3500 methyl-groups were radio-labeled in (B) at the start of the experiment, which correlates well with the minimum number (2800) of tactically active methyl-groups determined by  and suggests that parameters were chosen reasonably.