You Could put a screen in the middle. That will slow them down some. You could get some with smaller spaces and relly slow it down. You may have to cut the screen away if it has made its way past the holes. You could prob. raise the light too but maybe just alittle. They will make it if they don't dry out or burn. You could water them and then use one of them blown glass waters from wal-mart two for ten bucks. Might at least keep them from drying out. I dont know if I helped but thats what I would try.