Figure 4.

Manipulating the phenotype of grasshoppers causes them to change habitat use in the expected direction. (a) Grasshoppers (n = 30) painted dark (dark dots, right) are found more often on the dark laboratory habitat than grasshoppers painted pale (pale dots, left). Dots are individual means based on 20 observations. (b) Grasshoppers (n = 52) injected with the hormone corazonin become darker (right half of image) and are found on the dark laboratory habitat more often (dark dots) than untreated, pale grasshoppers (left half of the image and pale dots). Dots are individual means based on 20 observations. (c) Grasshoppers darkened by corazonin (right individual, n = 17) are mostly recaptured on dark asphalt, whereas pale control individuals (left individual, n = 14) are mostly recaptured on pale parking spaces and sidewalks. Background image: the dark asphalt road bordered by pale parking spaces and sidewalks. (Online version in colour.)