Awww! Mantises are more vertical climbers than horizontal climbers, so they love sticks, just like you have in your enclosure! Also, did you bake your stick? That will dry it and prevent it from growing mold and fungus and making your mantis sick!
Isopods are also wonderful cleaning crew for any left over bug bits from meals. I can't wait until I have my mantis numbers down to a reasonable enough number that I can make up living enclousers for them all with isopods, live plants/moss and springtails. It just makes life so much easier to not have to clean anything pretty much ever.
I believe there are places online that US residents can order isopods and springtails from but I personally just go out into my yard and flip over everything to collect woodbugs (isopods) and gather up leaf litter which pretty much always has springtails in it already.
So either wait til spring for a free supply or search around for somewhere to order from.