Praying mantids are in the order Mantodea, derived from the Greek word "mantis," meaning prophet, seer, or diviner. This is in reference to the common stance taken by these insects when the grasping front legs are held in front of the body giving the resemblance of being in prayer. Because they are predators, they are sometimes incorrectly referred to a "preying mantids" although the term certainly fits.
Seventeen species are found in the US, ranging in size from about 2 to about 4 inches. The two most commonly observed species in Nebraska are nonnative, the European mantid and the Chinese mantid. Chinese mantids are the largest and the ones commonly sold as garden protectors.
Mantids are fierce predators and are well designed for it. The rear legs are long and thin, allowing the insect to lunge at prey. Of course, the front pair of legs are held in the praying position and are armed with spines to securely hold the unfortunate victims. The triangular head with large eyes allows the mantid good depth perception and a wide field of vision. The head can rotate nearly all the way around, so the mantid can see completely around itself without moving its body. Some species can fly using their hind pair of wings, most often males searching for mates.
It is fascinating to watch mantids capture prey. They are mostly ambush predators that usually camouflage very well within their surroundings. They rarely move except for slowly tracking unsuspecting prey with their heads. When the prey is near they may use their legs to slowly lean forward if necessary to close the gap. Then comes the almost unseen lightning-like lunge with the front legs and the meal is securely in the grasp of the spiny vice-grips. In somewhat grisly fashion, mantids do not waste time killing their victims and calmly begin eating as the captive struggles unsuccessfully to free itself. Interestingly, some Chinese martial art styles mimic the slow moving motion with quick strikes and are named after the praying mantid.
Females are generally bigger than males, especially late in the summer as the abdomen swells with eggs. In an ultimate sacrifice, males are sometimes eaten by the females after/during mating, as the females are unable to resist a convenient source of nutrition for the developing eggs if sufficiently hungry. Not being completely blind to love, males of some species can gauge relative hunger of the females and use greater caution when approaching before mating. If the female is not too hungry, the lucky fella may escape to reproduce again.
Shortly after, the female lays a mass which may contain dozens or even hundreds of eggs, and covers it with a creamy material from her accessory glands. This solidifies into something that has the appearance and consistency of a packing peanut. This is the overwintering stage that is often found on plant stems and branches after the leaves fall. As the weather warms in the next spring, the eggs begin to hatch and it is each mantid for itself as the young hatchlings may devour each other.
Since mantids are fairly large, they are themselves are susceptible to predation by mice, birds, bats, and other animals. Like some other dusk/night flying insects like moths, they are able to detect the echolocation signals of bats with a special structure and go into evasive maneuvers when flying.
Like many insects that are released in gardens for biological control (i.e. lady beetles), they soon disperse and are probably not that effective for large scale removal of pests. Also, they are non-discriminatory in what they eat, including other beneficial insects. But they are sure cool to watch.
SOURCE: Bugs Rule! by Whitney Cranshaw and Richard Redak