Fig. 1.

Four digital moths shown on a sample of each of the three treatment backgrounds, in which the same dark and light pixel distributions are intermixed at progressively finer spatial scales. The moths in this figure evolved on the disjunct background and were among the most cryptic of the individuals in their population. Note that in the disjunct treatment (a), the moths are somewhat harder to detect on the patch that they most closely resemble but that all four can readily be located in a superficial scan. In the mottled (b) and speckled (c) treatments, the backgrounds incorporate high levels of noise at spatial frequencies comparable to the size of moths, and the moths are far more difficult to detect.