how many crickets are you giving your leo at one time? you should only give him as many as he can eat in 10-15 minutes and not leave any in the enclosure for over 24 hours. if there are a bunch hopping around after he has eaten what he wants they will become an annoyance and he will mostly just want to get away from them. heat and no water will kill crickets really fast. you need to keep a source of fresh food and water in with them at all times, not only to keep them alive, but to keep them gutloaded for your leo.