- Professor Grubbly-Plank: "Yes, these are Bowtruckles, and as Miss Granger righty says, they generally live in trees whose wood is of wand quality. Anybody know what they eat?"
- Hermione: "Wood lice. But fairy eggs if they can get them."
- — Professor Grubbly-Plank teaches fifth years about bowtruckles.[src]
Wood lice are crustaceans that live in trees. In appearance, they somewhat resemble grains of brown rice. They are a favourite food of Bowtruckles, and are offered to them by wizards and witches who wish to obtain wood from the tree they live in to use in making wands. Wood lice can also be used as potion ingredients.