Mantid fast facts
Mantids are also called praying mantis, and can be easily distinguished from the cockroaches by their strongly-spined raptorial front legs modified for seizing prey, and their long, narrow prothorax which forms a moveable neck.
They can be up to 150 mm long. And are usually well camouflaged to blend in with the plant stems and leaves. All mantids are carnivorous and use their front legs to catch their food. They will eat whatever they can hold on to, and even the very hardest parts of some beetles and wasps pose no problem to their very strong jaws which just keep munching through hard and soft parts. Their main prey is insects.
They are very picky and wasteful eaters, and often discard food after taking a few delicate bites.
They often display a swaying movement. It is thought they are trying to camouflage themselves by looking like a leaf stirring in the breeze.
Male mantids are usually smaller than the female, and may end up as a post-coital meal for the female, but this occurs more often in captivity than in the wild.
The eggs are laid in oothecae (egg cases). The egg case and eggs are pumped out of the abdomen as a frothy substance. This hardens on contact with the air to a tough material. Above you can see a female next to the egg case she has just attached to some twigs.
During her lifetime a healthy, well-fed female can produce a dozen or more oothecae. When the young hatch they resemble small worms, but soon moult into small versions of the adult form. When kept in captivity mantids should be separated as soon as they hatch or else each cage will soon contain just one well-fed mantid!
They make popular pets. In captivity they can be fed on flies (pet shops sell curly winged flies that can barely fly, so are easily handled) or crickets or anything that moves. I have even had one attempt to dine off my finger in preference to the small, juicy fly I was tempting it with.
The European mantid, above, when fully grown can reach 75 mm in length including the wings which, when folded stretch just beyond the tip of the abdomen. Males are thinner and shorter than females, but have longer antennae. Its colour varies from green to brown to blend in with the background. It can be found more-or-less worldwide as it is popular as a pet. It was introduced to North America from Europe in 1899 and again in the 1930s to control pest insects such as grasshoppers. It is the state insect of Connecticut.
They mate one a year and the male is sometimes eaten after mating. The female lays around 100 eggs in her ootheca (see the top photograph), which she cements to a branch or leaf. The eggs hatch the following spring.
When a mantid spots prey it often moves its head from side to side. This helps it judge how far away the prey is, and this is the same way we judge distances - it is known as binocular triangulation.