I feed mine crickets, depending on the size of the mantid depends on the size of cricket. I raise crickets also so I usually have a pretty good variety of crickets to feed. I sometimes put 1 or 2 mantids loose in my cricket bins and just let them eat what they want. I also spry them twice a day with water enough so there is drops of water on the sides for them to drink from. I’m not sure if this is the right way but it has seemed to work for me pretty good.