This page gives a brief guide to rearing mantids. Further information may be found in some of the books that have been published on mantids.
Choosing your mantis
The availability of species is constantly changing, so it is not sensible to become fixated on a particular species. The best choices for beginners are some of the typical mantids. Species of Miomantis, Sphodromantis, Polyspilota, and Tenodera are frequently available, relatively cheap, and usually easy to rear. Beginners should generally avoid the more exotic looking species - they are often more difficult to rear, and more expensive.
Whether to buy an ootheca, nymphs, or adults is very much a personal choice and is likely to depend on price and availability. Nymphs are usually cheaper than an ootheca or adult but a single nymph is no use if you intend to breed mantids. If you buy two or three nymphs they may not all survive to adult and you may end up with only one sex. Buying an adult female is risky, she may be old and about to die, or she may not have been mated. Oothecae are relatively cheap and have the potential to give you many nymphs, assuming the ootheca came from a mated female, has not already hatched, and has not dried out; unfortunately few breeders are willing to sell oothecae.
There are many possibilities for mantis cages. The main requirements are that the cage is escape proof, has a suitable surface on which the mantis can climb, and is at least three times as high as the mantis is long. A reasonably tall cage is needed to allow room for the mantis to shed its skin. If you wish to see your mantis you will need either the top or one side of the container to be clear; mantids can however be reared in translucent containers.
It is possible to keep mantids free-range, on pot plants on a window sill. The free range method usually has a high mortality rate with small nymphs because of spiders in the house.
Commonly used cages include disposable plastic cups, jam jars, and sweet jars; I have also used 35mm film canisters, supermarket salad pots, yogurt pots, margarine tubs, and even curry-sauce containers from the fish and chip shop! If the sides are transparent, the lid of the container can be made from nylon mesh (e.g. net curtain material), and secured with an elastic band. If the container is opaque, cling-film or polythene can be used to give a clear top.
One thing which should be considered when selecting the cage is the size of the mantis. It is best not to keep a single small mantis in a very large cage. A small cage means the food is always relatively close to the mantis and therefore easier to catch; this is particularly relevant if the prey is fairly inactive.
If you buy a mantis nymph from a specialist dealer it will probably be in a small clear plastic cup and you can and move it to a larger container as it grows. To provide them with a suitable surface to walk on, either put one twig diagonally across the pot, or hang some strips of kitchen roll down the sides. Leaving the bottom of the cage bare makes it easier to clean out and easier for the mantis to spot its prey.
Mantids are carnivorous, they feed on a wide variety of insects but prefer soft-bodied insects such as flies, crickets and moths, rather than hard insects like beetles. Although they seem to cope well with spiders and wasps, there is a risk that the mantis will be unlucky. Fast moving insects are more easily seen by mantids, but they can learn to spot and eat slower moving prey. Mantids can tackle surprisingly large prey, but as a rough guide aim to feed them nothing which is more than a quarter of their own body mass. Traditionally mantids are fed on fruit flies (Drosophila spp.) when small, and on crickets when larger.
Many people keeping small numbers of mantids buy their crickets from pet shops as they are required. If you want to buy livefood, consider visiting the local fishing shop and buying maggots as an alternative to crickets. Maggots are the cheapest form of livefood available in Britain. Mantids will eat the maggots or adult flies. Three sizes are available: Standard (large), "Pinkies" (medium), and "Squats" (small); they are actually three different species of fly. Maggots which are not eaten will pupate and emerge as flies 1-3 weeks later, depending on the temperature. Excess maggots can be stored in a fridge until needed.
The alternative to buying in food insects is to rear your own. There are various possibilities each with their own advantages and disadvantages. I generally rear the food for my mantids, the two main advantages are that the food is available whenever needed and the cost is much less. If you keep other insects, you should consider using surplus and damaged insects as mantis food.
Fruit flies, Drosophila spp., are the standard food for anyone feeding small mantids, or young nymphs. They are quite easy to rear, either on fruit or on commercially available artificial foods. The main problem is that they tend to get out and are always flying around the house. Their small size means they are only suitable for very small mantids; if you breed a large species you could find yourself keeping Drosophila all the time but only using them for very short periods when you have newly hatched nymphs.
Aphids (greenfly and blackfly) can be useful food for young mantids, especially if you don't normally keep a culture of Drosophila. Outdoors in Britain they are available from about April until September but you will need to look on different plants at different times of the year.
If you intend to rear food for a lot of mantids you will probably need to rear insects which have fast reproductive and growth rates, e.g. crickets, locusts or cockroaches. To keep the growth rates high, these insects need to be kept warm. Two species of crickets are commonly reared, the smaller Acheta domesticus and the larger Gryllus bimaculatus. Cockroaches are generally less desirable in domestic situations as the faster breeding species tend to be those most likely to escape and become established in the home.
If you only keep a few mantids there are various options. Mealworm beetles (Tenebrio molitor) can be used, both as adults and as larvae. They are simple to rear and provide a steady supply of assorted sized larvae as well as the adults. The main disadvantage is that mantids seem to need to learn to eat the larvae, second or third instar mantids which are fed on mealworms will happily continue to feed on them, adults which have not been reared on mealworms seem to ignore them most of the time.
Stick insects tend to be slow to reproduce so they are not suitable as food for large numbers of mantids but the common laboratory stick insect, Carausius morosus, is useful for anyone rearing a few mantids. Carausius morosus is easy to rear and it requires little attention to keep a colony; I find they are most useful as a backup supply of food for small mantis nymphs. The drawback with stick insects is that they tend to be slow-moving so mantids do not spot them very easily.
Breeding mantids is not difficult although there can be problems with mating them. The eggs are laid in cases called oothecae. When they hatch the young mantids, called nymphs, go through several stages (instars) before becoming adult. The nymphs shed their skin between each instar. The nymphs look like wingless versions of the adults although, in the later instars, the developing wings can be seen as small flaps. Most mantids have wings when adult so there is usually no difficulty in distinguishing the adults and nymphs.
There are a few records of parthenogenesis (reproduction without mating) in mantids but it is unusual. One species from the USA, Brunneria borealis, always reproduces by parthenogenesis because this species does not have males. If you have an unmated female of any other species and it lays an ootheca, don't give up all hope: there is a small chance that it will hatch.
Once the mantids are adult it is a good idea to allow about two weeks for the sexual organs to finish maturing before attempting to mate them. Mating mantids is always potentially disastrous because of the possibility of the female eating the male. The probability of this happening is actually quite small if the female is well fed.
Various strategies can be used to reduce the risk to the males. There are three main points to consider: make sure the female is not hungry, give the male room to escape and hide, do not disturb them during mating. There may be some courtship display prior to mating but often this is limited to no more than a cautious approach by the male. The male climbs on to the back of the female and then twists his abdomen to couple with the end of the female's abdomen. As soon as mating has finished the male should be removed.
Eggs are laid in groups surrounded by a protective foam, this mass is called an ootheca (plural: oothecae). An ootheca is produced as a froth which hardens on contact with the air, building up the ootheca can take an hour or more. The oothecae can contain as few as ten or over 200 eggs depending on the species. A female will lay 5-20 oothecae depending on the species. If the female is not well-fed she will lay small oothecae which contain few eggs.