Biology of praying mantises
Although not at first glance visible, mantises (Mantodea) are closely related to the cockroaches (Blattodea) and termites (Isoptera). The order Mantodea is divided into several families, with more than 2400 species. In Central Europe only one species (Mantis religiosa) occurs. The other species are found in the Mediterranean or in the (sub-) tropics. Common to all is the formation of the first pair of legs as fang arms. With these they catch their prey, which is mainly other insects or spiders. Many species have adapted to their environment in the course of evolution, blending into the background with their coulors and shapes. This camouflage is also called Mimese. However, if a predator comes too close, they can adopt a threatening attitude, in which they unfold the wings or fang arms and show their warning colours or imitate large eyes. Some species mimic the appearance of inedible ants in the newly hatched state (also called nymphs). The imitation of poisonous or inedible animals is called mimicry.
Like other insects, praying mantises have to skin (moult) themselves to grow. The larvae look already similar to the imagos (adult stages) and grow about one third of their body length with every moult. This form of development is called hemimetabol and is different from the holometabolic form, where the larva differs greatly from the imago and the development into a full-grown animal takes place in a single form, the pupa (example: butterflies). All in all, praying mantises need 6 to 10 moults, depending on the species, until they are adults. The first moult occurs immediately after hatching (and is then named L1 after this counting – it has a moult behind it, L2 has two moults behind it, etc.). Depending on the temperature and food supply, the subsequent moulting takes place every two to four weeks. Males often need one to two moults less than the females of the same species. Fully grown animals are winged and are called “adult”. One stage before it is called “subadult”, two stages before it is called “pre-subadult”. In exceptional cases, additional moulting occurs during development, for example in the case of prolonged cold, lack of food or if the animal has lost a leg which is gradually reproduced with the following moults. A praying mantis usually has a lifespan of less than a year in nature, but in captivity large species can live up to two years. Some species require hibernation, which is usually done at the egg stage.
Basically, all praying mantises in the adult stage are winged. However, the females are rather lazy and use their wings mainly for fall arrest or threat display. In some species (e.g., Parasphendale affinis), the wings of the females are even reduced. Males, however, are usually good flyers, as they travel at night, in the protection of darkness, following the pheromones (fragrances) of females, sometimes long distances.
A common (but not always easily recognizable) difference between males and females (sex dimorphism) is visible from the fourth or fifth moult (L4 / L5). In the females, the penultimate tergite (abdominal plate) at the end of the abdomen grows over the last, creating a large endplate. This is not the case for males. Thus, from L4 / L5 the males have two tergit plates more than the females (see gender determination). The difference between males and females, depending on the species, can also be expressed in terms of shape, colour and size. The latter is particularly strong in the Orchid mantis (Hymenopus coronatus), where the males reach only about one third of the body length of the females. Species-specific distinctions also in the Mantis lexicon.