Fig. 2.

Spatial mosaic formation by Müllerian mimics. Here, populations of the two species 1 and 2 were distributed in a regular grid (50 × 50 cells). Individuals of each species could occur in any one of ten different morphs (dominant colour morph in each cell shown for species 1 and 2). In any given time step, individuals can disperse (at low rates) to neighbouring cells, the local predator community continues to forage on a given phenotype in a given cell until a fixed number consumed, and the prey reproduced. Starting with a random distribution of morphs to cells (an extreme assumption generating high heterogeneity), the system soon reduces to one in which the two species in the same cell share the same appearance, with narrow ‘hybrid zones’ between races of the different phenotypes