I have a 18x18x24 Exo Terra tank featuring a rainforest-like environment with lots of plants and an established fauna of various invertebrates (springtails, isopods, snails, etc.). When my orchid mantis reached L4, I decided to release her into the tank to observe her behavior in a large, more natural setting. Today marks the sixth day since she was introduced into the tank and so far it's been very interesting to watch her.
The first day, she was quite passive, mostly staying in one spot. She did, however, actively hunt fruit flies. After a few days, I've seen increasing levels of activity. It seems that she likes to move a bit, then stay in one position for a few hours. When she spots reoccuring movement, she will soon move in to investigate and set up a new "ambush". She is remarkably effective at hunting in this large enclosure. I've added two grasshoppers, several wild flies (about the size of house flies) and a number of other flying insects. At first, she stalked the grasshoppers and caught one of them. After that, she moved up in the enclosure, finding new spots among the branches and leaves close to the top. In two days, all the flying insects disappeared. She is now quite fat so I will probably introduce less flying insects from now on. I did not anticipate such a high success rate.
Another observation is that when the lights go out, she will quickly move to a nearby leaf and climb it to hang upside down for the rest of the night. In the morning, she climbs down and starts moving around again. Could this be an instinct to protect her from nocturnal predators that move along the ground? When she's getting thinner and presumably more hungry, this seems to trigger more movement and more active hunting. Now that she's fat, she tends to stick to one spot for longer periods of time. I've also seen her return to the exact same spots where she's caught prey before. She'll sit there for many hours but if nothing shows up, she moves on.
The vivarium has different thermal layers, caused by the lamp. Near the top, the daytime temperature is 27-28 degrees C (80-82F), at the bottom it's 24 C (75F). Right now she's spending more time in the higher levels but that may be caused by her recent feast on flying insects. Humidity is steady at 85-99%, except for when the ventilation fan is running (4 x 15 mins per day). This causes a bit of a dry breeze which removes stagnant air.
I thought I'd share my observations with you guys in case you're interested. Personally, I'm fascinated to see the differences compared to when she was living in her small nymph enclosure. Although my vivarium is not her natural habitat, it at least mimics several aspects of it, which could trigger more of her instincts.
The first day, she was quite passive, mostly staying in one spot. She did, however, actively hunt fruit flies. After a few days, I've seen increasing levels of activity. It seems that she likes to move a bit, then stay in one position for a few hours. When she spots reoccuring movement, she will soon move in to investigate and set up a new "ambush". She is remarkably effective at hunting in this large enclosure. I've added two grasshoppers, several wild flies (about the size of house flies) and a number of other flying insects. At first, she stalked the grasshoppers and caught one of them. After that, she moved up in the enclosure, finding new spots among the branches and leaves close to the top. In two days, all the flying insects disappeared. She is now quite fat so I will probably introduce less flying insects from now on. I did not anticipate such a high success rate.
Another observation is that when the lights go out, she will quickly move to a nearby leaf and climb it to hang upside down for the rest of the night. In the morning, she climbs down and starts moving around again. Could this be an instinct to protect her from nocturnal predators that move along the ground? When she's getting thinner and presumably more hungry, this seems to trigger more movement and more active hunting. Now that she's fat, she tends to stick to one spot for longer periods of time. I've also seen her return to the exact same spots where she's caught prey before. She'll sit there for many hours but if nothing shows up, she moves on.
The vivarium has different thermal layers, caused by the lamp. Near the top, the daytime temperature is 27-28 degrees C (80-82F), at the bottom it's 24 C (75F). Right now she's spending more time in the higher levels but that may be caused by her recent feast on flying insects. Humidity is steady at 85-99%, except for when the ventilation fan is running (4 x 15 mins per day). This causes a bit of a dry breeze which removes stagnant air.
I thought I'd share my observations with you guys in case you're interested. Personally, I'm fascinated to see the differences compared to when she was living in her small nymph enclosure. Although my vivarium is not her natural habitat, it at least mimics several aspects of it, which could trigger more of her instincts.
Beautiful plants you have there in your vivarium... not to mention the mantis, lol! It is interesting that she's been so sucessful at finding and catching the food in such a comparitively large enclosure. It sounds like she probably is finding and eating most of the food you've put in there. One thing to consider though, is disappearence of the prey items due to other causes (natural death, etc.)... and there might be some that die and get lost in the foliage or underneath on the substrate. Just something to maybe think about and watch to make sure she's getting all the food you think she is. 
