Fig. 1. Experimental setup. A butterfly was placed on a 0.2 m high perch (referred to as start in analyses, 1) in the centre of the room, just on the border of the area viewed by the two CCD Trackit cameras (2 and 3) connected to a computer for storage of coordinates. A model predator (a black cardboard box 0.15 m x 0.15 m x 0.20 m; 4), situated 2 m from the perch, was released by hand to simulate attacks, stopping 0.15 m from the perch. Butterfly take off was also recorded by a digital camera perpendicular to the take off (5). To ensure flight into the area viewed by the cameras, a spotlight was placed in the ceiling (6), illuminating the perch where the butterfly started. Only the flight area of the room was illuminated by fluorescent lamps in the ceiling (the area marked by 2 m x 4.7 m), the rest of the room being unlit.