How sensitive are lizards to caffeine? I want to use spent espresso grounds as substrate for my BSF larvae feeders and am concerned if they eat the grounds that they will build up caffeine within their bodies and possibly present toxic levels to my Bearded Dragons. I have looked high and low to find some sort of study data related in any way to reptiles and caffeine and have had no luck. Any factual data or experience good or bad is welcome. Thanks!