[3] Their common name praying mantis is derived from the distinctive posture of the first pair of legs that can be observed in animals in repose.

This “tympanal auditory organ” is an unpaired structure found on the ventral side of the animal on the metathorax between the third pair of legs.

[11] The great variation in the coloration of M. religiosa from different shades of yellow, brown, green, and sometimes black has been the cause of numerous hypotheses and studies for over 100 years.

[8] This finding contradicts with Di Cesnola, who claims to have observed the animals within the same time and location (and therefore the same temperature).

In the last years, more reports have been made of the distribution of the animals in Northern Europe (Latvia, Estonia), as well.

[20] The sexual behavior of praying mantids in general is curious, so has received interest from scientists over the last century.

Since the foveae in his eyes face directly forwards, he has the most accurate and detailed view of her and can watch every one of her moves.

Depending on the environment, males sometimes show a light ‘rocking’-behavior which is believed to imitate the leaves of surrounding plants to blend in with the background.

His tibiae fit into a pair of grooves on either side of the female's mesothorax in front of her wing bases.

The genitals, which are found on the end of the abdomen in both sexes, look quite different; the males possess a pair of asymmetrical claspers, while the females have an ovipositor.

The abdomen of the male curves and twists in a 90° angle around the female's to insert the claspers between the ovipositor and the sternum.

The animals can stay in this position for four to five hours before a spermatophore is deposited inside the female and the claspers are withdrawn.

[7] Copulation usually takes place in September or October, but the eggs overwinter and the larva do not hatch until the following spring.

Very few animals (about 10%) survive this first instar stage due to lack of appropriately sized food, low temperatures, or insufficient humidity.

The fact that females need a longer time to develop and more moults might be due to the difference in size.

Lawrence compared the percentage of cannibalism in natural and manipulated (males and females were put close together in the field) pairings and found rates of 31% and 24%.

[24] The fact that sexual cannibalisation happens so often is surely also supported because a male without a head can continue and even initiate copulation.

[4] M. religiosa is a carnivorous ambush predator that actively scans its environment and feeds on most insects that are not too large to be captured by rapid extension of its raptorial legs.

[4] Grasshoppers seem to be rather popular, probably because of their type of movement (flying or leaping),[26] but crickets and cockroaches are also frequently preyed upon.

Some years ago, the general opinion was that they killed their prey with a bite in the neck before consuming it, but current observations do not support this; the animals just start eating the body parts closest to their mouths.

[8][22] The large compound eyes that account for a great portion of the head make clear that vision seems to be important for M. religiosa.

Their hunting behaviour and their sexual interactions rely almost exclusively on sight and the detection of movement.

[27] One compound eye of an adult mantid consists of 8,000 to 10,000 optically isolated ommatidia with an interommatidial angle of 2° in the periphery and 0.7° in the fovea.

[3][21] Interommatidial angles in insects vary from tens of degrees to 0.24° in dragonflies, which puts the mantids on the upper end of spatial resolution.

[29] The peering behaviour observed in M. religiosa is believed to be essential for the measurement of distances and depth perception; a side-to-side pendulum-like movement of the head or the whole body in a horizontal plane is used to scan the environment.

[21] The development of the visual system was reviewed by Karl Kral in 2014:[3] while high-contrast cues could be perceived by adults and nymphs (two hours to three days) alike, the differentiation between lower-contrast cues was much less successful in the two-hour-old animals, but a great improvement occurred after only three days of life.

While they already have all the necessary structures, very young animals have a restricted visual field and lower resolution and sensitivity to light.

The great improvement of vision after only three days happens due to the sclerotisation of the cuticle that includes the corneal lenses of the ommatidia.