 If the colors are linked to the amount of chemical defenses against insects, then the insects will avoid red leaves and increase their fitness; at the same time, trees with red leaves have an advantage because they reduce their parasite load.This has been shown in the case of apple trees where some domesticated apple varieties, unlike wild ones, lack red leaves in autumn.A greater proportion of aphids that avoid apple trees with red leaves manage to grow and develop compared to those that do not.