I had always thought that insects that only live part of the year (yellow jackets, praying mantids, etc) die off mainly as a result of low temperatures.
What if you were to keep them in an environment where the temperature was warm year-round? Would they live significantly longer?
It’s going depens on the exact species of Mantis you are concerned about. Under ideal conditions, a female mantis can live up to a year.
Wildeyedreptiles seems to have a lot of detailed information.
A friend of mine kept a madagasgar roach for a pet in one of those small aquariums with peat moss in the bottom - he fed it bananas and oranges, and occasionally meat I think.
It lived for about 5 years (it was pretty huge), but eventually it died of old age - I would assume that a mantis would be the same.
IIRC, You’d have to feed it live food, as they are not scavengers.
You can stab a piece of meat with a toothpick and wave it in front of the mantis. It’s not easy to convince it that it’s alive, but I’ve done it before. It will eat the meat off the toothpick and then drop it.
Also, you can hold a spoon with water and it will drink from it. Praying mantises are unusually smart and tamable for insects if you ask me.
One of the best routes is to feed it live crickets. That’s what I use for my lizards. They’re cheap (About 1.50 CDN for a dozen), easy to maintain, and readily available at many pet stores, albeit a little noisy unless you clip their wings. You can give the crickets viatmin-fortified cricket food, or dust them with a vitamin powder immediately before offering them to the mantis.