Heck yeah. If not, then I don't think they would be able to survive in such dense populations (camo not being enough). Communication by physical means like "boxing", using the antennae, etc., appears to be some ways that mantids communicate without killing each other. Obviously, both mantids will probably not be hungry or see the other as a desirable meal for it to be "willing" to communicate. Great observation though.
Yes, that really is good observation and has been the subject of at least one scholarly article (see if you can talk the rents into forking out $30 for a copy!):
http://www3.interscience.wiley.com/journal...864680/abstract.
There's no doubt that your nymphs are being "territorial" in a very limited sense. Mantids do not patrol and guard an area like a tiger or a Thompson's gazelle, and starvation will cause them to move to a different area, but if a wandering conspecific of about the same size approaches, he will respond to what is essentially a "fright reflex" (and I think that Marshall Edmunds uses that phrase in another paper) by retreating. This behavior reduces cannibalism and increases the odds that each nymph wil recieve an adequate number of prey, so it is likely to be selected for.
Many scientists, I have discovered, have a very fuzzy idea about language and tend to use it in specialized and often idiosyncratic ways. My hero, O.E. Wilson's specialized use of the term "social altruism" is a case in point. Whether or not we say that mantids communicate may be merely a matter of semantics. Obviously communication among eusocial insects, like the directional dance of honey bees is very different from a gesture made by a solitary insect like a mantis, and not just in complexity. Say that there was a kid at school who, whenever you got within ten feet of him became terrified and started screaming. Presumably, you would move out of range if he started to scream, until he stopped, but I doubt if you could call the manifestation of his terror communication.
In any event, keep on observing, keep a cogent record of your observations, and research their meaning as best you can, including by asking questions here.
rchids
