Oak trees provide essential food for many animals in the scrub. Leaves are eaten by a wide variety of insects, such as grasshoppers, katydids, caterpillars, leafminers, gall-making wasps, and beetles. Tree- and leafhoppers suck sap from twigs and leaves. Acorns, the fruit of the oak tree, are favored by weevils and other insect larvae, squirrels, deer, bear, and birds, including the Florida scrub-jay Oaks and acorns contain chemicals called tannins that help protect them from being eaten. Many kinds of moth caterpillars , and a few butterfly caterpillars, feed on scrub oak leaves.
Some caterpillars eat entire oak leaves.
Others make irregular holes or notches in the leaves. Others eat the green parts of the leaves and do not eat the leaf veins, leaving a brown network of veins. Some very flat moth caterpillars feed inside the leaf, between the upper and lower surfaces, and leave behind a brownish or whitish blotch or twisting line. Some kinds of caterpillars use silk to sew together overlapping scrub oak leaves and then feed within this shelter. However, so many birds and insects feed on caterpillars, their numbers are usually kept down to a reasonable level.