|Acorn Weevil grub next to a dime for size comparison. The dark particles are frass and a you can see a couple of holes in the acorn itself.|
Acorn Weevils (Genus Curculio) are a type of beetle that feeds inside nuts such as oak acorns. Like all weevils, they have extremely long snouts as adults which they use to pierce and feed. The female adult Acorn Weevil drills a hole in a forming acorn and lays her eggs inside. The little grub is plump and light colored, feeding inside the nut until the Fall. The acorn is eaten away from the inside and often you can find the tell-tale hole. They will feed on almost any oak species.
In the Fall, the acorn falls and the grub somehow manages to squeeze out the small hole. Squirrels do not eat the damaged acorns and they will not germinate. When collecting nuts for planting, a good test to see if you have viable acorns is to give them a "float test." You drop the acorns in the water and observe them. Those that sink are okay and weevil free. The ones that float or sink very slowly releasing air bubbles are occupied. They float due their light nature and air in the eaten nut.
The larvae (grub) buries itself in the ground to pupate after emerging. It may take up to 5 years for it to emerge as an adult weevil and start the process all over. I had heard the weevil grubs were edible and so decided to find out first hand if that was so.
I have eaten beetle grubs before, notably the large Suri beetles grubs in the jungles of Peru, but these were small and a first for me. They were actually a bit rubbery and not as creamy as the Suri grubs. You would need a lot to fill you up, but I guess would be a good source of protein. I've been told they taste better if quick fried in butter, maybe so. They were not particularly appetizing to me.
Here's a video from the Capital Naturalist YouTube Channel detailing my experiment:
Here's me eating a Suri grub in the Peruvian jungle for comparison: