PEPPERED MOTH - Melanic and Typical Form (Biston betularia). The peppered moth has 2 colour forms, a normal light colour & a darker melanistic form. The dark form is an interesting example of industrial melanism. Over a period of time in the industrial areas, where vegetation is affected, the darker individuals have been more successful in avoiding predators. So the melanistic gene has had a survival advantage and now predominates in many industrial regions in the UK, Europe & US. In less polluted areas the light form survives well & the melanisitc gene does not have the advantage so the light form predominates.