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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.
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