I'm trying to make some sawdust/wood-shaving based formicaria for Camponotus, and walnut has a nice coloration that will let me see the brood.
I am a bit wary, however, as black walnut can be dangerous/deadly to some animals. I do know that in nature, carpenter ants *do* infest walnut trees, but I'm wondering if there are any risks to using walnut dust/shavings for queens and colonies?