Fig. 1.

Equipment used for prey-choice testing. (A) Testing arena for motionless-lure tests. The apparatus consisted of a glass arena (square box, 100×100 mm, walls 35 mm high), with a removable glass lid. Holes in the box connected with four ‘choice’ vials flanked by lures. Lures in position ‘a’ are different from lures in position ‘b’. (B) Testing apparatus for moving-lure tests. A 35 mm deep rectangular glass box (pale grey) with a glass lid sat on top of a wooden stand (grey). Moving lures were controlled through a camera release-cord. The ‘choice area’ is the dark grey semicircular area within wire circles. (C) Apparatus for virtual-prey testing. Images pass from a data projector lens through a second lens (for reducing image size) onto a stimulus screen positioned in front of the higher end of the ramp.