NOVEMBER
2010

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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11-25-10

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Prayerful Mantids Not as Pious as They Look


Praying mantids are some of the most easily identified of the insects. Mantids are fairly large and slow-moving. Therefore, relative to most insects, mantids are easy to spot. The structure of a mantid is also quite distinctive. They have a long, slender prothorax. That's the part of an insect to which the head is attached. A human with a comparable build is sometimes called long-waisted.

Most mantids have relatively large heads but, unlike most insects, they have a neck and can turn their head from side to side. This ability means that mantid behavior is sometimes suggestive of the memorable -- and oft-repeated -- line from the movie "Casablanca": "Here's looking at you, kid!"

More than 2,000 species of mantids have been identified, and most are found in tropical regions of the world. More than 20 species are found in the United States. Like other groups of insects, some species of mantids have managed to expand their distribution by hitching rides in stuff shipped by humans. Such is the case with some of the mantids that live in the United States.

Chinese Mantid
Chinese Mantid

In his 1901 book "The Insect Book," early-American entomologist L. O. Howard reports on two such introductions. The European mantid was first reported in New York state. This insect most likely arrived in the country as an egg case attached to nursery stock. Another species of mantid arrived about the same time from Japan; it also probably traveled in the egg stage. One of the largest species of mantids found in the United States is the Chinese mantid. As its name suggests, it, too, is an introduced species.

Chines mantid egg case
Chinese mantid egg case

All species of mantids produce Styrofoam-like egg cases, called ootheca, which are glued to some surface. Most mantid ootheca are found attached to stems of plants, although the structures can occasionally show up on a flat surface, such as the leg of a picnic table or even a window pane. Mantid eggs spend the winter enclosed in the ootheca. A single ootheca may contain as many as 300 eggs.

Mantid egg cases are fairly common in nature but go unnoticed by most people. Author Annie Dillard once wrote, "I have just learned to see praying mantis egg cases. Suddenly I see them everywhere." Dillard's statement supports my contention that most people are blissfully unaware of praying mantid egg cases in their lawns and gardens. But Dillard, and coincidentally my computer spell-checker, bring up another point: Are these creatures properly called mantids or mantises?

Not everyone agrees, but one argument would be that all of these insects should be called mantids. Why? Because the order name to which they belong is Mantodea. Within the Mantodea is a genus name Mantis, so members of that genus could correctly be called mantises; however, the insects in all other genera should be called mantids. So while all of the insects in the order Mantodea are mantids, some -- but not all -- are mantises. So unless you know what species you are talking about, go with mantid to be correct.

Popular or so-called common names have always been a source of confusion when identifying insects, and mantids are no exception. They were called praying insects in England because when at rest they appear to assume a position of holding a prayer book. They have also been called sooth-sayers. In Southern states these insects are sometimes called rearhorses because they rear up when attempting to catch prey. They have also been called mule killers because of the assumption that the brown liquid that sometimes oozes from their mouths could be fatal to mules. The name devil's coachman apparently arose because the insects sometimes appear to be holding the reins of a horse-drawn coach.

Regardless of the name almost everyone recognizes that praying mantids are predatory insects. They capture prey with their grasping front legs and are vicious predators. Their prey includes all types of insects, and in the case of the female, sometimes even her own mate becomes a meal. Because they are predators many people want praying mantids in their gardens as biocontrol agents.

Exactly how beneficial praying mantids are for control of pest insects is questionable. But this "pseudo-saintly bug," as called by Ogden Nash, does eat insects. So most gardeners like to spy it praying for its next meal!

 

Writer: Tom Turpin
Editor: Olivia Maddox