Why do some butterflies have holes in their wings?

A question we often get asked is about why some butterflies have holes in their wings or look old and ratty. Butterflies wings actually wear out when they fly. When a butterfly emerges out of the chrysalis the wings are small, crumpled and wet but the abdomen is swollen with fluid. The butterfly pumps this fluid into double tube veins in the wings which expands them until they are flat, then they hang until the wings are dry. Once the wings are dry they are dead tissue and cannot be repaired. The wings are covered with tiny modified hairs or scales and as the butterfly flaps and flies the scales fall off so their wings wear out over time. Depending on how active the butterfly is dictates how long the wings last. A nervous flighty butterfly will only live a few weeks were as a butterfly which is more relaxed about life can last quite a lot longer.