Praying mantis

How it works

A mantis waits motionless on a stem, camouflaged, and swivels its head to track prey. It strikes with front legs lined with sharp spines, which pin the prey while it is eaten. Nymphs start hunting as soon as they hatch, and their first meal is often a sibling. They grow through the summer and take larger prey as they go. Adults mate in late summer, and the female sometimes eats the male. She lays her eggs and dies when it freezes. There is one generation a year.

The egg case, or ootheca, starts as a frothy mass that hardens into a crusty, Styrofoam-like shell on a twig, stem or other surface. It holds anywhere from a dozen to 400 eggs, depending on the species. A Chinese mantis case is tan, about as long as it is wide, and the size of a ping-pong ball, like a toasted marshmallow on a twig. The eggs overwinter, and the nymphs come out in spring almost all at once. A case brought indoors will hatch in the house in winter. Iowa State advises keeping a collected case in a box or jar in an unheated garage or porch, and watching for the hatch from about mid-May. If the nymphs cannot scatter within a day or two, they eat each other.

The native Carolina mantis (Stagmomantis carolina) is the smallest; the adult female's wings reach only three-quarters of the way down her abdomen. The European mantis (Mantis religiosa) is tan to bright green and has a round black spot, sometimes white-centred, under the base of each foreleg. The Chinese mantis (Tenodera sinensis) is the largest, pale green to tan, with a green line along the edge of the forewings. The Missouri Department of Conservation suggests that the introduced species may be outcompeting native mantids. It suggests selectively destroying Chinese and European mantids and their egg cases, and leaving the native Carolina alone. It also notes that large Chinese mantis females have occasionally been recorded eating small reptiles, amphibians and even hummingbirds.

What it is confused with

Only one of the three common mantises is native. Their egg cases are also easy to confuse with the egg masses of two pests, which you should destroy.

1. Also goodCarolina mantis — The native species. It is smaller, about 2–2½ inches, pale green to tan or mottled grey. The adult female's wings stop three-quarters of the way down her abdomen. Leave it and its egg cases alone.
2. PestSpongy moth egg mass — Tan and fuzzy rather than hard and foamy, about 1½ by ¾ inches, laid flat on trunks, stones, walls and outdoor furniture. It holds up to 1,000 eggs. Scrape it into soapy water. See spongy moth.
3. PestSpotted lanternfly egg mass — Flat rows of eggs about an inch long, under a coating that turns from creamy white to pinkish grey, then tan and cracked. It is laid on bark, stone and vehicles. A mantis case is a raised, rounded foam. Scrape it off; see spotted lanternfly.