The invention relates to N-substituted acyl-imino-pyridine compounds of formula (I), to the enantiomers, diastereomers and salts thereof and to compositions comprising such compounds. The invention also relates to methods and uses of these N-substituted acyl-imino-pyridine compounds, and of compositions comprising thereof, for combating and controlling animal pests. Furthermore the invention relates also to pesticidal methods of applying such N-substituted acyl-imino-pyridine compounds. The N-substituted acyl-imino-pyridine compounds of the present invention are defined by the following formula I: wherein p, X, Y, W1, W2, W3, W4, Het, R1, R2, R3a, R3b, R4a, R4b and R5 are defined as in the description.
