Beneficial Insect — Praying Mantis
Praying Mantises belong to the family Mantidae and the order Mantodea. Most are mantids tropical or subtropical
however many species are found in North America. The three most common species the European Mantis (Mantis
religiosa), the Chinese Mantis (Tenodera sinensis), and the Carolina Mantis (Stagmomantis carolina). Of these, only
the Carolina Mantis is native to the continent, The European and Chinese species were introduced in the 20th
century as predators in an attempt to control pest populations in gardens.
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The Carolina Mantis, Stagmomantis carolina, is a medium-sized mantid native to North and Central America. This
species has a long thorax, and the head and thorax combined are almost as long as the abdomen. The wings are
relatively short, especially in females, and don't reach the tip of the abdomen. The color ranges from mottled
grayish-brown to greenish-yellow with bright green wing covers and legs.
Like other mantids, this species is a generalist predator of arthropods, but it has also been reported to attack small
frogs and lizards. It grabs its prey with its enlarged, raptorial forelegs. Both the femur and tibia are adorned with
strong spines to provide a secure hold on the prey.
Adult females are 47 to 60 millimeters in length while adult males are usually about 54 millimeters in length. 1st instar
nymphs are 7-12 millimeters in length. When the nymphs eat more their abdomens get much longer. The Carolina
mantis has a dusty brown, gray, or green color useful as camouflage in certain environments. The Carolina mantis'
color varies because the nymphs are able to adjust their color to match the environment they are in at the time of
molting. They can adjust their color over each molt, if necessary, until they reach their final molt to adulthood. An
unusual trait is that its wings only extend three quarters of the way down the abdomen in mature females; this trait is
also seen in Iris oratoria, which can be distinguished by the large eyespots on the hind wings (inner-wings) of both
adult male and female Iris oratoria. Both adult male and female Stagmomantis carolina have a dark coloured dot on
each of their forewings (outer-wings) which may be partially hidden in a brown or dark colour morph individual
The Chinese mantis (is a species of praying mantis native to China and other parts of Asia and islands of islands off
of mainland Asia. At around 18
Tenodera sinensis feeds primarily on other insects, though adult females in particular sometimes catches small
vertebrates. For example, they have been documented as feeding on small reptiles, amphibians and even small
species of hummingbirds. Also like most mantids they do not generally avoid toxic or venomous prey, however they
have been observed eating the larvae of monarch butterflies, but discarding the entrails.
The Chinese mantis is a long, slender, brown and green praying mantis. It is typically longer than most other praying
mantises reaching just over 11 centimeters, and is the largest mantis species in North America (spread throughout
much of southern New England, and the Northeast United States). Its color can vary from overall green to brown with
a green lateral stripe on the borders of each side of the front wings in the brown color form. In low light the eyes of
the mantis appear black, but in daylight appear to be clear, matching the color of the head.
Mantis religiosa is a mantis species native to temperate areas of Europe, Asia and northern Africa, but has spread
around the world and is now well established across the United States and into Canada. Outside of Europe it is
known as the European mantis; in Europe, it is known simply as the preying mantis. It was introduced to the eastern
US in 1899. In 1977 it officially became the state insect of Connecticut. The European mantis is 5-7.5 cm longusually
a shade of green with brown, usually well camouflaged in its surroundings, and also difficult to see because of its
usually motionless stance.
Although a carnivore and an impressive predator, this mantis is completely harmless to humans and a beneficial
species in that it eats many harmful insects, including the gypsy moth caterpillar, many aphids, flies, mites,
grasshoppers and, when an individual comes upon another mantis, will show cannibalistic behavior. Thus,
European mantises are solitary insects, coming together to mate only once a year. Females are known to eat the
males after mating.
Praying mantids undergo simple or incomplete metamorphosis, with three life cycle stages: egg,
nymph, and adult. Females lay 200 or more eggs in a frothy mass called an ootheca, which
hardens and protects the eggs as they develop. The nymph emerges from the egg mass as a
tiny version of the adult mantid. As it grows, the nymph molts until it develops functioning
wings and reaches adult size. In temperate climates, adults live from spring to fall, when
they mate and lay eggs, which over winter.
Soon after mating, a female praying mantis deposits a mass of eggs on a twig or other suitable structure. She may
lay just a few dozen eggs or as many as four hundred at one time. Using special accessory glands on her abdomen,
the mother mantid then covers her eggs with a frothy substance, which hardens quickly to a consistency similar to
Styrofoam. This egg case is called an ootheca. A single female mantid may produce several oothecae (the plural of
ootheca) after mating just once.
Praying mantids typically lay their eggs in late summer or fall, and the young develop within the ootheca over the
winter months. The foamy case insulates the offspring from the cold and provides them with some protection from
predators. Tiny mantid nymphs hatch from their eggs while still inside the egg case.
Depending on environmental variables and the species, the nymphs may take 3-6 months to emerge from the
ootheca. In spring or early summer, the young mantids make their way out of the protective foam case, hungry and
ready to hunt other small invertebrates. They immediately begin to disperse in search of food.
Mantids will eat butterflies, moths, flies, small wasps and bees, true bugs and caterpillars. Although they are considered
beneficial insects because of their voracious appetites, mantids will eat almost anything they can catch and therefore
do not differentiate whether their meal is beneficial to man or not.
The female praying mantis is often painted as an evil seductress, a cannibalistic lover that lures males closer, only
to eat them after mating. Is her reputation deserved? Does praying mantis sex always end in cannibalism of the
Rumors of the praying mantis' cannibalistic tendencies began when scientists observed their mating behavior in a
laboratory environment. Entomologists would offer a captive female a potential mate and would quite often be
horrified to watch the female bite the head or legs off the smaller male—sometimes even before mating. After the
male had served his copulatory purpose, he was nothing more than a good meal for the female and her upcoming
After scientists started observing praying mantis sex in a natural setting, the story had a different ending, which is
good for the males. When unconfined by laboratory terrariums (and not starving), the majority of praying mantis
mating ends with the male flying off unharmed. By most estimates, sexual cannibalism by praying mantis females
occurs less than 30 percent of the time outside the lab. Those are better odds for the fellows than what had been
seen in the lab. Praying mantis sex, it turns out, is really a rather romantic series of courtship rituals and dances
that typically ends satisfactorily and safely for both parties involved.
Given a choice between females, male praying mantises will move toward females seen as less aggressive (i.e.,
ones they hadn't just seen eating another male) more often than the more aggressive females.
The males also tend to prefer to mate with females that appear fatter and more well fed than others, as the skinnier
and hungrier mantises are more likely to eat their mates during or after sex. This could also point to the males
being more attracted to females that are healthier, for the betterment of their offspring.
There is a decided advantage for the female if she does decide to behead her lover. The praying mantis; brain,
located in his head, controls inhibition, while a ganglion (group of nerve cells) in the abdomen controls the
motions of copulation. Absent his head, a male praying mantis will lose all his inhibitions and consummate his
relationship with wild abandon.
And what if she's hungry? For certain, a slow-moving and deliberate predator like the praying mantis is not going
to pass up an easy meal. If a male makes the unfortunate choice of a hungry female for a mate, he's probably going
to be toast after they've mated.
A twist: Being eaten by the female paradoxically may mean that that particular male has more of his genetics
making it to the next generation if more of his sperm fertilize his mate's eggs while she is eating parts of him. More
eggs are laid by females who eat their mates as well (88 vs. 37.5 in one study). However, if a male can mate more
than once, that also increases his odds of having his genetics passed on.
A praying mantis has two large, compound eyes that work together to help it decipher visual cues. But strangely,
the praying mantis has just a single ear, located on the underside of its belly, just forward of its hind legs. This
means the mantid cannot discriminate the direction of a sound, nor its frequency. What it can do is detect
ultrasound, or sound produced by echolocating bats. Studies have shown that praying mantids are quite good at
evading bats. A mantis in flight will essentially stop, drop, and roll in midair, dive bombing away from the hungry
predator. Not all mantids have an ear, and those that don't are typically flightless, so they don't have to flee flying
predators like bats.
The praying mantis is so named because when waiting for prey, it holds its front legs in an upright position as if
they are folded in prayer. Don't be fooled by its angelic pose, however, because the mantid is a deadly predator. If
a bee or fly happens to land within its reach, the praying mantis will extend its arms with lightning quick speed, and
grab the hapless insect. Sharp spines line the mantid's raptorial forelegs, enabling it to grasp the prey tightly as it
eats. Some larger mantids catch and eat lizards, frogs, and even birds. Who says bugs are at the bottom of the
food chain?! The praying mantis would better be called the preying mantis.
Try to sneak up on a praying mantis, and you may be startled when it looks over its shoulder at you. No other
insect can do so. Praying mantids have a flexible joint between the head and prothorax that enables them to
swivel their heads. This ability, along with their rather humanoid faces and long, grasping forelegs, endears them
to even the most entomophobic people among us.