Acorn Weevil (Curculio sp.) Hole in Acorn Cup

The hole in this acorn's cup was likely made by an acorn weevil larva (Curculio sp.). The larvae develop inside the nut and chew exit holes (~3 mm across) when they are mature and ready to hibernate in the soil.

Fun fact -- Acorns inhabited by weevil larvae may later be colonized by ants (Temnothorax sp.), which specialize in living inside damaged acorns. The ants clean the acorn out and make it their home.

Habitat: Found in a mixed forest; Note the white fungus on the acorn.