I also think that enclosure size does factor into the growth potential of a mantis. I watched a documentary on TV about dinosaurs and there were a group of dinosaurs that lived on an island. These dinosaurs, which were the same species as their counterparts on land, didn't reach nearly the size as the ones did on the mainland. Fossil evidence supports this, however another observation I've made, which could be wrong, is that humans on smaller pieces of land grow shorter. For example, the average Japanese person doesn't get very tall, where as Chinese in their larger land-mass, can get tall. I really don't know for certain, but it seems logical to assume they do grow smaller in small enclosures. Perhaps there is someway to devise an experiment to prove this one way or another. This has peaked my interest and I'd really like to know what the truth on the matter is.