Fig. 2. (A) Diagram of the apparatus used to demonstrate that a dorsal region of the field of view is used for polarization analysis by lycosids. (B) Raw responses of spiders (Pardosa tristis) to rotation of a polarizer (right) and a neutral density filter (left). The filled circles indicate the starting point of the spider. The arrowheads indicate the commencement of filter rotation. For further details, see text.