hi. they are not canabalistic as long as they have lots of fruit flies to eat, they generally run away when they bump into each other. or display, and then run away! i never saw them stalk each other, although i wouldnt totally trust hungry adult females. you can feed them on ff till they are nearly full grown as they are a v small mantis. adults can take green bottles or medium bluebottles as they are quite strong for there size. even my adult females would eat ff. newly hatched its worrying as can barely even take a ff, but they do eventually get stuck in.this is important. i lost alot of mine to shedding problems, (their rear legs kept getting stuck) so keep the humidity fairly high. spraying every couple of days should be enough esp when they are going to shed. you might want to use a lamp to get temps of 25c + too as they like high temps!