If you’ve taken a walk outside lately, you have probably noticed there is a new bug in town. The praying mantis, named for holding its front legs “prayer-like” in front of its body, is paying a visit to Iowa because of several consecutive mild winters.

“Because of the mild weather we are seeing, praying mantids survive a little farther north in the state than they used to,” said Donald Lewis, professor of entomology.

Lewis said praying mantids – the plural form of mantis – have never been numerous in Iowa and historically have been common only in the far southeastern corner of the state.

This summer, two different types have been spotted as far north as Ames and as far west as Cedar Rapids – the Chinese, up to 5 to 6 inches long, and the Carolina, up to 2 to 3 inches long.

Kenneth Holscher, associate professor of entomology, said although Iowa’s recent winters may have helped the population grow, it is probably only slightly.

Holscher said people may just be more observant.

“If there is an increase, then it could be because of weather patterns, but there aren’t really much more [than previous years],” he said.

The natural life cycle of praying mantids is to eat and grow during the summer and then mate and lay eggs in a stiff, foamy case in the fall. The adults die either from freezing or old age, and if the winter is mild, the cycle will repeat itself the following summer. There is one generation per year.

Some say praying mantids are great for keeping campus vegetation alive and green, because the mantids are said to eat “bad bugs” that damage plants and flowers, but Holscher disagrees.

“They are indiscriminate,” he said. “They don’t pick and choose [what they eat], but there probably aren’t enough to tell if they are damaging or aiding our campus vegetation.”

Although they may be interesting to watch, Holscher doesn’t recommend capturing and keeping the adults.

“Students should allow the females to lay their eggs first, so that we have a nice-sized population next year,” he said. “And by this time of year, it is almost pointless since they will all be dead in about a month.”

Daniel Eisenrich, junior in health and human performance, has been keeping a pet praying mantis for about three weeks now.

“It was the first one I had ever seen, so I caught it,” Eisenrich said. “It’s pretty big. I think it’s a female.”

A common myth about praying mantids is that they are “sexual cannibals” – meaning the females eat their partners after mating.

Lewis said this usually only happens in a controlled environment and is not a good representation of how praying mantids behave in the natural world.

Praying mantids do eat each other occasionally, however. Along with eating other large insects such as butterflies, bees and crickets, they will also eat their siblings if hungry enough.

How do they eat such a large meal with such a little head?

“They wait and ambush,” Holscher said. “They are very fast. They grab with their legs and keep the prey in their grasp with spines on their front legs. They don’t need a big head, just slowly eat away.”

Praying mantids also eat their prey alive.

“I catch crickets and grasshoppers for mine,” Eisenrich said. “It catches them around the neck and eats the head first while it’s still alive. It eats the guts and the shell just dangles.”

Although that may sound vicious, Lewis said the mantids are no threat to humans.

“Just keep your fingers away from their front legs and out of their mouths,” he said.