Rick Prouty was cleaning his backyard pool when he noticed something unusual on his fence: a praying mantis. The 4-inch long insect, not native to northwest Iowa, may have flown up on wind gusts from more southern locations, according to a professor of entomology at Iowa State University. [Click to enlarge]

Sitting on the fence in his Le Mars backyard was a 4-inch praying mantis.

"I didn't even know they lived up here," he said. "I've only ever seen them on National Geographic. I've never seen one up close."

A Chinese mantis, like this one found in Le Mars, likes to eat live prey, catching them with the sharp spikes on its speedy front legs. [Click to enlarge]

A praying mantis rarely ventures this far north, according to Professor of Etymology Donald Lewis of Iowa State University (ISU).

"It's a southern instinct, introduced to the Southeast in the late 1800s for pest control," he said via phone from Ames Thursday.

The one on Prouty's fence was a Chinese mantis.

Over the years, these insects, originally from China, migrated across the Southeast, even as far as Missouri, he said. Lately a few have been reported in the southeastern most tip of Iowa.

"Only in the last few years have we seen them in Ames," Lewis said. "Any farther north, and it's a blessing to see them."

Well that blessing was Prouty's Thursday. The leggy beast stayed for more than an hour on his fence.

Lewis offered the theory that the Chinese mantis flew to Le Mars on a wind gust.

"I don't think they're surviving from the egg stage here, otherwise we'd see them in the adolescent stages, but we've only seen them in the adult stage, and no one ever calls one in until September, when they're adults," he said.

The life cycle of a mantis is to grow in the summer, then mate and lay eggs in a stiff foamy case in the fall, according to an ISU article. In winter, adults die of old age or freeze. The eggs survive the winter -- if it's mild enough -- then hatch and repeat the cycle the following summer.

The Chinese mantis, which enjoys live prey, can be a helpful insect, Lewis said. They eat backyard pests like crickets.

"Their big front legs are for snapping live prey," Lewis said. "Within nanoseconds those front legs zip out and back, and by the time you can blink, they've started to eat their prey alive."

Mostly they stick to insects like crickets, grasshoppers, butterflies and bumblebees, Lewis said, but one mantis was observed eating a hummingbird.

The mantis isn't a threat to humans, Lewis said.

"I have handled one, and if you get your fingers into their front arms there are really sharp spines that could draw blood," he said. "Just keep your fingers out of their mouth."