Effects of animal camouflage on the evolution of live backgrounds

Research on camouflage focusses on the ways animals make themselves inconspicuous against their background (Thayer 1909; Cott 1940; Ruxton et al. 2004). A common means of achieving inconspicuousness involves crypsis via background matching. In the visual domain we focus on here, this means possessing a phenotype that matches the colours, patterns and brightness of its surrounding background (Stevens & Merilaita 2009). The traditional focus on animals being the active players that match themselves against a passive background is well justified when the background is not a live entity. In many cases, however, animals’ immediate surroundings are either plants or larger animals. Examples include ambush predators on either flowers or foliage, herbivores on plants and small parasites on large hosts. In such cases, the background organisms may actually be active players that coevolve with the animals that use them as a backdrop. This important feature of animal camouflage requires detailed evaluation.