What to Do About a Praying Mantis on a Houseplant

Indoors

• Although a homeowner might not want a praying mantid flying around for long, pests can become a problem in homes since their natural enemies are not inside. Praying mantids like to hang out on plants and feed only on living prey, such as flies and mosquitoes. They also eat aphids, which damage and even kill houseplants. Consider leaving the mantid on the plant for a while, to take care of insects that might be about to infect your plants. According to Galveston County Master Gardeners, the mantid is also the only insect that eats moths and the only predator quick enough -- with its grasping forelegs -- to catch mosquitoes and flies. Note that, as The Ohio State University Extension reports, praying mantids do not bite humans, carry disease nor damage household furnishings.

Beneficial Insects

• Praying mantis are considered "beneficial insects," in that, like ladybugs, they eat living insects that damage plants. So don't kill it. Capture the one on the houseplant in a jar or box and release it onto a garden plant, particularly in an area with plant-damaging insects, although a praying mantis cannot provide a lot of insect control. Capture the mantid by cupping your hands around it or gently coaxing it into the container. Although praying mantids don't bite, you might feel a pinch from the "spines" on their forelegs. For a flying mantis, the University of Arizona Center for Insect Science Education Outreach recommends using an insect net. Carefully lay the net over the top or to the side of the mantid and use one hand to gently push the mantid into the net and cover it. Transfer it into a container with a lid and release it outside.

Killing a Praying Mantis

• If you're not interested in keeping the mantid alive, it can be drowned with a spray of water. (You might need to carry the plant outside to do this.) Although a rumor occasionally makes the rounds that it's illegal to kill praying mantises in parts of the United States, that rumor is not true, Snopes.com reports.

Egg Cases

• Females lay up to 400 eggs -- depending on species -- in the fall in a frothy liquid that hardens and can be sticky. If you find an egg case, remove it from the plant stem by cutting the stem a bit lower than the egg case and put it outside. Vacuum up any nymphs -- which look like small adult mantids -- that have escaped or catch them and release them outside.