In our opinion, oak leaves are a must for keeping many species of roaches. About 90% of our colonies have crushed oak mixed in with the substrate and/or with a layer of whole oak leaves on the surface. They provide natural cover for nymphs and shy species (especially Ectobiids) and they are also a food source for many others. In fact, a significant amount of a wild roaches' diet is decaying leaves. These are Gambel oak leaves collected from various montane regions of Arizona (they are free of pesticides). They have been hand filtered from pine needles and other debris and are ready for use, though we suggest boiling them to sterilize. These are the ideal food source for leaf loving species such as Arenivaga, Macropanesthia, Therea, Oxyhaloa, etc. They range from about 1"-4" in size. These are also great for the bioactive, naturalistic vivarium.