The "peppered" pattern is for camouflage amongst lichens on tree trunks, walls etc. There are darker and lighter forms and this moth is a famous example of natural selection. In the 19th and 20th centuries the darker forms became much more common in towns, where tree trunks and other surfaces were darkened by sooty pollution and so they were better camouflaged and survived better than the paler moths. Meanwhile the paler forms remained more common in the countryside where the air was cleaner and their camouflage was more effective. More recently, as sooty air pollution has been reduced, the dark forms have become less frequent even in towns, as well as the countryside. Which form is surviving in your garden? The Peppered Moth is night-flying and comes to lights. In its resting position it measures up to 5cm across. (Photo: C Manley)