Peppered Moth - melanic form / dark phase. (Biston betularia). Essex, UK. 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 &