In which we wake up one morning to discover that we waited to long to roast the chestnuts we harvested. What are these white grubs? What kind of insects will they grow up to be?
It turns out they're the larvae of the chestnut weevil, probably either Curculio elephas or Curculio sayi. The female weevil lays eggs on the young chestnuts about 3 or 4 weeks before they ripen and fall from the tree. After they fall, the grubs emerge and dig down into the soil, where they will stay for a couple of years before reaching their adult form and starting the cycle all over again.
I had wanted to know if there's any way to tell whether grubs are in chestnuts before they emerge - that is, how do I know that nuts are safe (i.e., bug-free) to eat? The answer: you don't know. If you want to minimize the chances of a delicious grub snack, collect nuts quickly after they fall and boil them for 20 minutes in order to kill the bugs (which will hopefully be too small to notice). Then freeze for later or roast and eat.
If you can handle seeing some grubs, love some buggy science, and want to know what "curculio" means and how it connects these bugs to both ancient Roman theater and Jake and Maggie Gyllenhaal, check out the video!
(If there's anything I love in the world, it's learning something, documenting it, and then sharing it with other people. Hooray for the power of photography in the education process!)