Air-flow experiments were conducted in polypropylene open- flow tunnels (40 cm wide, 80 cm long, 40 cm high) (Figure S1). Each tunnel was open at both ends and a fan was located at one of these openings to cause a continuous air flow (30 cm s21) that flowed across from ‘emitter’ to ‘receiver’ plants through the tunnel. Four tobacco plants (WT or NtOS2 plants [emitter plants]) and four lima bean or maize (receiver plants) were placed 30 cm apart for 3 days. Hereafter, the receiver plants are referred to as VOCos- receivers and VOCwt-receivers, according to the emitter plants’ characteristics (NtOS7 or WT). During treatments, the tempera- ture was maintained at 25uC with a photoperiod of 16 h. The light period was from 7 AM to 11 PM. After 3 days, the plants were used for herbivore treatments.