Terrariums and Cages
Cage Size
The rule of thumb in size is: The cage must be 3 times the mantis length in height, and 2 times the length in width. Meaning that it should be taller than it is wide. This allows the mantis to have adequate space to molt.
Mantids usually hang from a high place to shed their exoskeleton. They hang downward from the old exoskeleton while pumping fluid into their new soft skin, growing to their new size. If the container is too small, they wont have space and will often have a mismolt. Some of the largest species can reach over 6 inches in length so their cage should be at least 18 inches tall by 12.
Its often good to start the mantis in smaller containers and increase the size as they grow. If your mantis is small and is in a large terrarium, it may not be able to find its food. Young nymphs should be kept in a container with very fine mesh ventilation to prevent fruit flies from escaping.
Ventilation
Its important to have some way for air to flow in and out of the habitat. Often this is achieved with a mesh or fabric lid. Popup butterfly cages are good for species that cant climb well or need extra ventilation.
Specific insect acrylic terrariums with laser cut ventilation holes can be found on many custom craft sites or insect hobbies sites. Zilla micro terrariums are a personal favorite. On a budget holes can be cut out of Tupper-ware containers and fabric or window screen hot glued in place.
16oz and 32oz insect cups with fabric waffle lids are perfect size for nymphs and even smaller adult species as they provide enough ventilation and keeps even small fruit flies from escaping. Larger Insects can be kept in glass aquariums with mesh lids.
Fruit flies can squeeze out of small holes so be sure to find appropriate sized mesh or screen for your feeders along with your mantis.
Heating
Mantids require different levels of heat and humidity depending on where they originate. Its best to try to replicate their natural environment to have the best results raising your mantis. Species from tropical regions often have higher heat and humidity requirements and will not do well if levels drop down lower than ideal. Species from deserts can require higher heat but less humidity. Temperate species can have a large range and can do well with fluctuations.
Maintaining these levels can be a challenge.
Heat lamps can be positioned above terrariums or heating pads can be place on the sides or under the habitat to increase ambient temperatures. If you have a species that requires specific temperatures, have a trial run with your set up before the mantis arrives. Monitor the temperatures for a few days and adjust as needed. Make sure to measure the temperature at the top and bottom of the enclosure. If you just measure in one location you could have a hot spot that can overheat your mantis.
Humidity
Humidity levels can be maintained by your substrate and misting. Using a substrate such as coco fibers and sphagnum moss is a good way to maintain humidity levels. It will hold on to moisture longer than just paper towels. It is also more resistant to mold.
Misting is vital for keeping humidity levels elevated and providing mantids with a source of drinking water. Some mantis require up to twice a day misting to maintain adequate humidity levels while others can go up to a week. Its important to research the requirements for your species.
A mesh terrarium will loose moisture faster than one with glass or acrylic walls. Tropical species do better with in enclosures that retain humidity, while arid species can do better with a mesh that allows the moisture to dry quicker.
Lighting
Mantids are very visual and need some form of lighting to hunt. Unlike reptiles they do not require a UV light. A simple lamp near the cage is fine on a budget. You can even keep them near a window as long as they are out of direct light.
They thrive best with a typical day night cycle.
Many aquarium lights are available on the market that can be used. LEDs lights are preferred to prevent heat spikes. A mantis eyes will turn a dark color when they are in dark conditions. If you have a glass or acrylic cage do not place into direct sunlight as this can cause heat to build up inside the cage.
Cleaning
Terrariums will need periodical cleanings to remove waste and prevent mold. Remove your mantis and all decorations. Use bioactive cleaning soap/sanitizers and hot water for cleaning when possible. Diluted vinegar is also a good cleaning solution. Be sure to rinse cleaning products off all surfaces before putting your mantis back inside.
Cleaning frequency depends on the size of the mantis, the size of the habitat, and substrate. Weekly to biweekly cleaning is recommended.