This is general care information pertaining to most mantid species. Click on the links on the right for more detailed care for those specific species. If you have some information that is important that I seem to have missed, please email me and I will add it.
I would suggest a container that is at least 2 times the width and 2 and a half times the height of the mantid. You must give it enough space to molt. Keep in mind that if you have sticks and leaves in the enclosure, the height from the lid to the sticks is what needs to be 2 and a half times the length of the mantid. Unless you are sure that your mantids are a communal species, I would not recommend keeping them together in one enclosure. You also should not put the mantid in too big of an enclosure. A half-inch mantid nymph may have a really difficult time finding food in a 10 gallon tank filled with plants, unless of course you are adding a large amount of food.
You should feed your mantis on its natural foods (flies, butterflies, moths) as much as possible. I use fruit flies for hatchlings. These can be purchased online or even many pet shops. There are 2 different types of fruit flies that you can use: Drosophila melanogaster and Drosophila hydei. I usually keep mantids together at L1 until about L3. D. melanogaster multiply fast, so there is always a good supply if you are feeding many nymphs. Drosophila hydei are a larger species of fruit fly, longer life and slower reproduction. I myself prefer to use hydei as I have found that most nymphs are able to handle these just fine even at L1. They provide a larger meal, and so less feeding is needed. Do your research on the species of mantid that you have so you know its size. Some species such as S. pretiosa and Otomantis sp. (boxer mantid) need smaller prey and have a very hard time handling D. hydei. Around L4 and up, I try to feed a variety of insects, such as moths, houseflies, roaches, and the occasional cricket or mealworm. The best of these are the flies and moths as these are more of its natural foods.
Most of the time, you will notice when your mantid is near molting. It will stop eating, and seem to ignore prey. That is usually the easiest way to tell when your mantis is about to shed within the next day or 2. It may also strike at the prey, seemingly missing it, but it is only trying to scare off the prey. If this occurs, take any food out of the container, as you don’t want anything interrupting your mantids molt. When your mantid starts to shed, do not bother it, don’t pick up the container to get a better look, and definitely don’t try to assist it. The mantid will shed its skin and sit there hanging for a bit to dry off. Do not feed the mantid for about 24 hours after it molts, but its ok to spray the container as long as your not spraying directly on the mantid after it molts as you want it to be able to dry correctly. Molting happens approximately every two to three weeks depending on the age of the mantid. The final molt usually takes around 4 weeks or longer depending on species.
Two weeks after their final molt your mantids MAY be ready to mate. Some say to wait for 3 or even 4 weeks, but I usually wait two. Some say to introduce the female into the males container, as he knows his area already. I choose to let the male into the females container. I doubt it really matters. I put some food in for her and when she starts to eat I set the male into the container. It’s usually instant that the male notices the female and begins to make his move towards her, but it can take a few minutes to a few hours. I personally stay there and keep an eye on them until mating commences. If they don’t begin mating within 30 minutes I remove the male and try later. If the female tries to attack the male or is not receptive at all, I wait a few days to a week before reintroducing them. I also make sure to introduce them in a good sized enclosure. A 10 gallon tank or bigger with a few branches is nice. After mating, the male will need space to run away from the female, or she may eat him. Mating can take a few hours, and unless you plan to be there watching the whole time, give your male some sprinting room.
Depending on how long you waited to mate your female and how well fed she is, she may start laying ootheca 1 day to 2 weeks after mating. She may lay them on the lid of the enclosure or on sticks provided for her. Keep the ootheca at the same humidity and temps that you would the adult mantid, and around 4-6 weeks later, it will hatch and the cycle begins all over again.