Species spotlight: mantids
By Clara Wodny on September 10, 2024 in Blog
Once you’ve seen a praying mantis, they won’t be difficult to identify. Named for their apparent piety — the way they hold their front legs in front of them, as though praying — these slender, unique insects have many fascinating qualities.
Mantis or Mantid?
Many people will refer to all mantids as a praying mantis, but that identification is not always accurate. The moniker ‘mantis’ technically only refers to a specific genus of the insects, while ‘mantid’ encompasses the entire group. Put simply: all mantises are mantids, but not all mantids are mantises.
There are over 2,400 documented species of mantids in the world, with just 22 species found in North America. Iowa only sees two species regularly: the Chinese mantis (Tenodera sinesis) and the Carolina mantis (Stagmomantis carolina).
Unique Features
Across the many different species of mantids, there is plenty of variation in size, color and other features. But all of the long, spindly insects do share some defining traits.
A mantid’s front legs are called raptorial legs, because of the way they are modified — with long, sharp spines — to grasp prey. Mantids also have an elongated thorax (the middle section of their body) that functions similarly to a neck and enables them to swivel their heads. Mantids are the only insects in the world capable of turning their head a full 180 degrees.
Mantids have two large compound eyes on the sides of their head, but these aren’t their only eyes! They have five total. The two compound eyes are very sophisticated and are used for seeing movement and some depth of vision. The three smaller eyes, called ocelli, are used for detecting light sources. All the mantid’s eyes work together for one purpose — the optimal persecution of prey.
Carolina mantis
In terms of Iowa’s mantids, the Chinese mantis is larger at 3-4.25 inches, while the Carolina mantis is a mere 1.75-2.5 inches. The Chinese mantis is not native to Iowa and poses a threat to several native species. Due to their large size and aggressive nature, Chinese mantises will outcompete Carolina mantises for food, as well as occasionally consuming Carolina mantises, various pollinators and even small hummingbirds.
Chinese mantises tend to be mostly brown in color, with a green stripe along the outside of their wings. Carolina mantises, however, could be a variety of colors. The nymphs (young mantids) can adjust their color to best match the environment they are in at the time of molting. They can re-adjust their color during each molt until they reach adulthood.
Chinese mantis, photo by Larry Reis
Life Cycle
Mantids develop through three life stages: egg, nymph and adult. The entire life cycle typically lasts about one year.
In the fall, female mantids will lay a group of up to 400 eggs in one smooth, hard-shelled mass called an ootheca. Mantids will lay their oothecas in a variety of areas but tend to prefer smooth, somewhat hidden surfaces such as plants and branches. An ootheca keeps the eggs safe overwinter, until they finally hatch in spring.
Once the weather begins to warm and spring arrives, the mantid eggs will start hatching. The new mantids are called nymphs, and look very similar to full grown mantids, only much smaller and without any wings.
After a few weeks, the nymphs will be fully grown adult mantids. Mantids mainly spend the summer eating and growing, before it is time to mate, which typically occurs near the end of summer.
Mantids are carnivores, and they are not picky eaters. They will eat any insect — and sometimes other small animals — that they are able to catch. They are such voracious eaters, that they are not even above cannibalism. Newly hatched nymphs will frequently eat each other, especially when they are in an area that doesn’t have an immediate food source, or if there are too many of them and not enough food to go around.
Cannibalism is known to occur during mating as well. Typically, male mantids will cautiously approach a female, performing some kind of mating ritual to avoid being attacked or eaten by the female. It is estimated that about 30% of mating attempts will end with the female consuming the male’s head.
The lucky mantids who make it to the fall without being cannibalized will eventually die as the weather gets colder. In the spring, when the new oothecas begin hatching, the population completely regenerates.