Figure 1.

(a) Detail of one of the streets sampled, showing the stretch of dark asphalt in the centre and pale sidewalks (tiles) and parking lots (cement) on both sides. (b) Comparison of the degree of crypsis of pale and dark grasshoppers on pale (tile) versus dark (asphalt) habitat. Grasshopper images are standardized digital photographs of a pale (18% blackness) and a dark (74% blackness) individual, each superimposed on both background types to facilitate comparison. Background images are digital photographs (corrected using a reflectance standard) of a representative sidewalk tile (left) and asphalt pavement (right) of the study area. (c) Digital photographs of grasshoppers under standardized conditions illustrating natural variation in body colour from the upper to the lower extremes of the colour distribution. From left to right, estimates of blackness for these individuals are 18, 27, 35, 45, 58, 69 and 74%. (Online version in colour.)