I have seen old, worn out butterflies with torn wings – sometimes very asymmetrical – still able to fly. I have also seen brand-new butterflies which have to have absolutely perfect wings in order to fly at all – even a slight bend near the margin is a fatal defect. Why is this? If old butterflies do okay flying on ragged wings, why must a new butterfly have perfect wings?
You can adapt to the gradual deterioration or loss of something much easier than have to deal with it straight out of the box so to speak.
The aged butterfly that has nicks and chomps out of its wings already knew how to fly, it just has to work a little harder at it now.
Plus many butterflies winter as imago, so they’re expected to get out in spring as very worn, it may have an effect.