Fig. shows the empirical distribution of optimal hyperparameters during the K = 3-folds crossvalidation routine. The mode of the distribution of the optimal C parameter for the MACCS-FP-SVM is 0.1. The mode of the joint distribution for the optimal walk length L and SVM C parameter for the L-RWGK-SVM is L = 4 and C = 0.001. In conclusion, the pesticide molecules were best described by random walks of length L = 4 for bee toxicity prediction. The optimal C parameter tended to decrease with the walk length, consistent with the view of the inverse of C as a regularization parameter expected to increase when the representation of the examples is more complex.