Video tracking platform. A stationary camera is mounted above a microtitre plate which is placed on top of a backlight unit with ventilation at the left. Wells in the microtitre plate contained a leaf disc and an aphid (a). Cling film was wrapped around the plate to prevent aphids from escaping. The camera was connected to a computer with EthoVision® XT video tracking software (b). Movements of the aphid’s centre point were automatically tracked (red track shows movements across 30 seconds). With this information the software calculated aphid velocity (line graph) and estimated probing (purple bar) and non-probing events (green bar).