Naturally Curious: Praying Mantis; Preying Is More Like It
Picture this: you take a cockroach and give it enlarged, muscular front legs equipped with spikes. You make its neck flexible and then stretch out its thorax. What you’ve created is its closest relative, a Praying Mantis. Somehow mantids (see note at end of this column) escaped the bad notoriety of roaches — perhaps because they don’t tend to invade human households. Whatever the reason, mantids have been a source of intrigue for humans for centuries. The Greeks considered them prophets. The French believed mantids could lead lost children home, and the Chinese used them to treat a number of illnesses.
There is no shortage of mantid species — there are 1,800 worldwide, located primarily in the tropics, with� 20 species in North America. Mantids were introduced into North America in 1869 to control insect pests. In the Northeast, there are three species of mantids, the most common of which is the European Mantis (Mantis religiosa), commonly known as the Praying Mantis. It is approximately two inches long and is the only mantid species in Vermont and New Hampshire. Northern New England is at the northern edge of its range, and thus, finding a Praying Mantis is fairly unusual.
One look at the physical attributes of a Praying Mantis tells you why it’s such a formidable predator: angled and enlarged front legs equipped with spikes for snaring and pinning prey, a short but very flexible neck which enables it to be the only insect that can look over its shoulder, five eyes which allow it to detect prey 50 feet away, and green or brown cryptic coloration.
Exactly how does a Praying Mantis utilize these adaptations to procure its prey? Usually it waits motionless (and well camouflaged) until a meal comes within striking range, but occasionally it slowly pursues prey until it gets within reach. The actual strike is phenomenally fast — 30 to 50 thousandths of a second. As for the prey it secures with these attributes, they are tremendously varied in types and sizes. Twenty-one species of prey have been documented, including insects, turtles, mice, frogs, birds and salamanders.
Perhaps most renowned of the Praying Mantis’s behaviors is its unusual form of copulation, referred to as “sexual cannibalism.” Typically, the male stalks the female prior to leaping onto her back. The female reaches over her shoulder and begins to chew off the male’s head. Once the head is removed, the male’s abdomen begins a series of movements, which eventually achieve fertilization. It has been recorded that a male whose head is eaten before it can mount the female is still capable (without its head) of walking around the female, climbing on her back and mating. According to Stephen Marshall, in Insects — Their Natural History and Diversity, the biting off of the male’s head severs a nerve that normally inhibits the male’s sexual movements. The head itself is also a rich source of protein for the egg-laying female.
Once copulation has taken place, the female lays anywhere between 50 and 300 eggs. They are laid in the middle of a foamy mass called an ootheca that she whips up and then shapes with appendages on her abdomen. This walnut-sized mass is usually attached to a twig, often in an overgrown field. It is soft and sticky at first, but soon becomes hard and water-repellent. The eggs overwinter and hatch in the spring. Tiny Praying Mantises emerge from the mass through a special section of pliable overlapping scales. They look much like the adults, but lack wings. The newborn’s first meal is often its own sibling.
Having forelegs in a position of prayer and being a voracious predator, Praying Mantises are often referred to as “Preying” Mantises. The physical traits and behavioral quirks of these close relatives of termites and cockroaches make mantids a unique and fascinating insect worthy of observation if you’re lucky enough to find one.
Note: Members of the Mantidae family of insects are referred to as “mantids.” The common name of some species, such as the European Mantis or Praying Mantis, uses “mantis” instead.
Mary Holland is the author of “Naturally Curious: A Photographic Field Guide and Month-by-Month Journey Through the Fields, Woods, and Marshes of New England” and “Milkweed Visitors.” She has a natural history blog which can be found at www.naturallycuriouswithmaryholland.wordpress.com .