This can happen if the food insects being offered are too big for the mantis. Young mantids can be particularly timid, so we recommend food insects about 1/3 the body size of the mantid to be safe. Not wanting to eat (and running away from live food) can also be an indicator that your mantid is preparing to moult (ecdycis). Mantids typically stop feeding a day or two prior to moulting and resume a day or so afterwards. Live insects can interrupt the moulting process which can result in the death of your mantid pet, so remove any live insects from the enclosure promptly if the mantis isn’t interested in feeding.