We have three huge compost bins about 8 feet diameter and 2 1/2 feet deep made from fiberglass rings cut from old underground storage tanks. Have used them for years to make great compost from oak leaves, llama manure, coffee grounds, kitchen scraps, etc. This year we have these enormous grubs that we've never had before. Attached photo shows one of the big ones next to the regular size grub, June bugs, I think, like we've had forever. Now there are very few of the small ones but 3 to 5 of the huge ones in every fork full of compost when I'm turning it.
Anyone know what they are and if I should kill them or let them work the compost?