A praying mantis was spotted in the garden west of the greenhouse earlier this summer. Working over there last week, I saw a mantis (the same one?) in the same place. Its colors had changed from the bright green of early summer to a duller green and brown that perfectly matched the maturing plants I was now cutting back for the winter. I began to wonder about the praying mantises and their habits. Do they live in the same place all season? I know they are considered beneficial insects, but what do they eat? Here is what I found:
The praying mantis is named for its prominent front legs, which are bent and held together at an angle that suggests the position of prayer. The larger group of these insects is more properly called the praying mantids. Mantis refers to the genus Mantis, one of fifteen in the order Mantodea.
By any name, these fascinating insects are formidable predators. They have triangular heads poised on a long “neck,” or elongated thorax. Mantids can turn their heads 180 degrees to scan their surroundings with two large compound eyes and three other simple eyes located between them. They have excellent vision and can detect motion, light, and shadow up to 50 feet away.
Most mantids are 2-6 inches long. Typically green or brown and well camouflaged on the plants among which they live, mantids lie in ambush or patiently stalk their quarry. They use their front legs to snare their prey with reflexes so quick that they are difficult to see with the naked eye. Their legs are further equipped with spikes for snaring prey and pinning it in place.
Moths, crickets, grasshoppers, flies, and other insects are usually the unfortunate recipients of unwanted mantid attention.They eat what we consider pest insects and also what we consider beneficial insects. However, the praying mantis will also eat others of its own kind. The most famous example of this is the notorious mating behavior of the adult female, who sometimes eats her mate just after—or even during—mating. Yet this behavior seems not to deter males from reproduction. [ ! ] Females regularly lay hundreds of eggs in a small case, and nymphs hatch looking much like tiny versions of their parents. The nymphs are also known to cannibalize each other if slower moving brothers and sisters are encountered before other food sources.
There are about 2,000 species of mantids worldwide, with about 20 species native to North America. Contrary to popular belief, none of the North American mantids are endangered. Two species, the Chinese Mantis and European Mantis, were purposely introduced to control pests. Egg masses and live insects can both be purchased for release. Although nymphs and adults alike eat indiscriminately, their voracious appetites do help control some insect pests in the garden.