i think you'll find everything you need under the "biodegradeables" section on the biodude's website (although you could find this stuff anywhere)- stuff like sphagnum moss, bark pieces, and seed pods will all be broken down over time by isopods. i always find my isopods flocking under cork bark.
https://www.thebiodude.com/collectio...le-leaf-litter
https://www.thebiodude.com/collections/seed-nut-pods