full size White Oak (Quercus alba) is the Illinois state tree.

Several species of insects parasitize oaks, producing galls on the leaves.

The Acorn Weevil is a beetle that lays eggs in acorns; after the larvae finish their development in the nut, they exit through the shell and burrow into soil to pupate.

The half-eaten acorn is often then parasitized by the Acorn Moth caterpillar.