Nope, nothing between the pages except a little air space. I take the ad/circulars/inserts (grocery adds, coupons, etc.) that come in the mail or stuffed in the center of most newspapers and just thrown the whole thing in there. If it's a full sized paper, then it is folded in 1/2 lengthwise, then I fold it again width wise (so quartered size? Hope that makes sense). So depending on how many pages there are in the item, it could be 10 "pages" thick, or even more. Each individual layer creates another "condo space" for beetles (about to pupate as well as pupa already there until they hatch) primarily and worms secondarily.
When I check on them or need to add carrots/veggies/moisture sources, I just pick the paper up by the fold, and "shake it out" to get all the critters out from all the various levels, or as many as I can get to fall out, then add the moisture source and put the paper right over the top of everything. They very quickly crawl back between the layers again. Any excess moisture on the food source is wicked up into the paper rather than down into the substrate, thereby helping prevent mold issues too.