Praying Mantis: Are They Harmful, What They Eat, Egg Cases
A praying mantis is a large ambush predator that is harmless to people: Ohio State and University of Kentucky entomologists say mantids do not bite humans, and none of the US species stings. Three species account for most mantids seen in US yards: the native Carolina mantis and the introduced Chinese and European mantises. All three eat whatever they can catch, bees and butterflies included, which is why extension services rarely recommend buying their egg cases for pest control.
Most people searching for a mantis have just found one on a porch screen in late summer, or a brown foam lump on a shrub in winter. Below: how to tell the species apart, what the egg case means, what they eat, and the one case where removal makes sense.
Which mantis is it? The three common US species compared
Colour is no help: Ohio State notes that green and brown forms occur in all three species. Size, wing length and two small markings do the job.
| Chinese mantis | European mantis | Carolina mantis | |
|---|---|---|---|
| Scientific name | Tenodera sinensis | Mantis religiosa | Stagmomantis carolina |
| Status | Introduced, about 1896, near Philadelphia | Introduced, first reported 1899 in New York State | Native |
| Adult length | 65 to 127 mm (about 2.5 to 5 in); the largest | 50 to 76 mm (2 to 3 in) | 48 to 65 mm (about 2 to 2.5 in); the smallest |
| Key marking | Green stripe along the edge of the front wings | Bull’s eye spot on the inside of each front leg | Dark spot on the forewing; mottled grey, brown and white |
| Wings (female) | Reach the tip of the abdomen | Reach the tip of the abdomen | Cover only about two thirds to three quarters of the abdomen |
| Egg case | Beige, roughly cube-shaped with rounded edges, 1/2 to 1 in across | Foam case; less distinctive, ask for an ID | Long, slender, grey-brown with a pale midrib |
| Where our data finds it most | Iowa, New Jersey, Pennsylvania, Illinois | Idaho, Utah, Montana, Colorado, Washington | Georgia, Kansas, Nebraska, Missouri |
Sizes compiled by The Pest Control Brief from Utah State University Extension, University of Kentucky ENTFACT-418 and Kentucky Critter Files, and Ohio State Ohioline ENT-67. Egg cases from NC State Extension and University of Illinois. State leads from our iNaturalist analysis below.
The wing test is the quickest field check in the East. NC State Extension describes the Chinese mantis as “up to 5 inches long” with wings that run the full length of the abdomen, against 2 to 3 inches for the Carolina mantis, whose wings reach about two thirds of the way. Ohio State puts the Carolina female’s wing cover at three quarters. Either way, a stubby-winged, mottled, smaller mantis in the East or South is almost certainly the native one.
Two other insects get mistaken for mantids. Walking sticks are long and thin but lack the grasping front legs. Mantidflies, relatives of lacewings, look like miniature mantids but are much smaller and have thin, clear front wings, according to the University of Kentucky.
What is a praying mantis?
Mantids are the insect order Mantodea, whose closest relatives are cockroaches and termites. Strictly, “mantis” is the genus Mantis, and “mantid” covers the whole group, a point Kentucky, Utah State and Wisconsin extension all make; in everyday use the names mean the same thing. Counts of world species vary by source: University of Wisconsin gives 1,500, Utah State about 2,000 and UC IPM over 2,000. Wisconsin and Utah State both put the US total at about 20 species.
The “praying” pose is the folded front legs, which are lined with spines that lock prey in place. The head swivels about 180 degrees on a flexible neck, according to UC IPM and Kentucky. Mantids hunt by sitting still on flowers and stems and striking at anything of the right size that moves. They are clumsy fliers; males fly more than females, and Wisconsin notes they are sometimes drawn to lights at night in late summer.
How the two introduced species arrived
A 1932 paper in the Bulletin of the Brooklyn Entomological Society records the first Chinese mantids at Meehan’s Nursery in Germantown, Pennsylvania, in about 1896, from egg masses that came in on nursery stock from Japan. The same paper notes the European mantis was first reported around Rochester and Ithaca, New York, in December 1899. NC State adds that European egg cases were later imported on purpose in the 1930s and sold for garden pest control. The Carolina mantis is native from New York south to Florida and west to Utah, Arizona and Texas, according to Ohio State.
Where each species is seen: our iNaturalist analysis
The three species split the country more cleanly than most field guides suggest. We counted research-grade iNaturalist records for each species per 10,000 observations of anything in each state, which corrects for states where more people record wildlife.
| State | Chinese mantis | European mantis | Carolina mantis |
|---|---|---|---|
| Idaho | 0.53 | 40.86 | 0 |
| Utah | 5.38 | 28.21 | 0.3 |
| California | 0.5 | 6.25 | 0 |
| Iowa | 25.72 | 0.29 | 22.99 |
| Pennsylvania | 14.42 | 3.46 | 10.23 |
| New Jersey | 14.6 | 4.48 | 12.77 |
| New York | 8.69 | 5.1 | 1.66 |
| North Carolina | 9.73 | 0.02 | 20.35 |
| Georgia | 6.57 | 0.01 | 27.6 |
| Texas | 0.05 | 0.03 | 3.61 |
Records per 10,000 iNaturalist research-grade observations, all years. Source: The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026.
West of the Rockies, nearly every mantis recorded is European: Idaho logged 1,838 European mantis records and 24 Chinese. In the South, the native Carolina mantis dominates; Georgia has 4,237 Carolina records and one European. In the Northeast and Midwest the Chinese mantis and the native overlap, and in Pennsylvania the Chinese mantis leads.
These are records of where people photographed mantids, not population counts. UC IPM lists at least nine mantid species in California, so a California mantis is not automatically European.
When mantids appear, and what the egg case means
All three US species have one generation a year. Females lay eggs in autumn in a frothy mass that hardens into an egg case, or ootheca, fixed to twigs, stems, fences or walls. The eggs overwinter inside, nymphs hatch in late spring (from late winter in parts of California, per UC IPM), and they grow through summer to reach adulthood in late summer. The adults die with the first frosts.
Our seasonality index shows all three peaking in September, when adults are full grown and most visible: 424 for the Carolina mantis, 367 for the European and 275 for the Chinese, against a yearly mean of 100. The Chinese mantis keeps a much higher share of records through winter (94 in February, against 19 for the European and 16 for the Carolina). The most plausible reason is its large, conspicuous egg case, which people photograph on bare winter stems; iNaturalist records do not separate life stages, so treat that as an inference.
How many babies come out of one egg case?
Dozens to a few hundred. Kentucky and Utah State give 12 to 400 eggs per case, and Ohio State up to 400. Illinois estimated about 100 hatchlings per Chinese mantis case, each about a quarter of an inch long. Many hatchlings are eaten by their siblings, and Kentucky notes that spiders, birds and larger mantids eat plenty more, so cannibalism and predation keep numbers in any one patch low.
One practical warning from Kentucky: an egg case brought indoors in autumn will hatch in the warm house during winter, whether or not you are ready for it. Leave cases outdoors on the stem.
What do praying mantis eat?
Anything they can grab. Extension lists include flies, beetles, crickets, moths, grasshoppers, caterpillars and spiders. Young nymphs take aphids and small flies; adults ignore small prey, so Penn State’s eOrganic guide notes that a late-season aphid problem is unlikely to be solved by adult mantids. Ohio State, Utah State, UC IPM and Washington State all list bees and butterflies among their prey, and NC State photographed Chinese mantids eating a swallowtail, a hummingbird moth and a carpenter bee in a pollinator garden.
The hummingbird records
Mantids also catch small birds. A 2017 review by Nyffeler, Maxwell and Remsen in The Wilson Journal of Ornithology compiled 147 cases of mantids catching birds, involving 12 mantid species and 24 bird species in 13 countries. More than 70 per cent of the cases were in the US, where mantids often wait at hummingbird feeders and flowers; the ruby-throated hummingbird was a frequent victim. Both introduced and native mantids were involved, and the authors advised “great caution” when releasing mantids for pest control.
Are they good for the garden? What extension services say
Mantids are counted as beneficial insects, but the extension view of buying them is cool to negative. Their appetite is the problem: a mantis eats the pollinators and other predators that a garden needs as readily as it eats pests, its cannibalism caps how many can live in one area, and Kentucky notes that released mantids tend to wander off.
| Source | Verdict on mantids as pest control |
|---|---|
| UC IPM (California) | “Of no benefit for biological pest control”; each one eats relatively few insects |
| University of Wisconsin | Not particularly useful for biological control; eat pollinators and beneficials |
| University of Kentucky ENTFACT-418 | Beneficial, but value relatively small compared with lady beetles and green lacewings |
| University of Illinois | “A mixed blessing”, eating beneficial as well as harmful insects |
| Utah State University | Not the most effective biological control agents |
| University of Georgia | Very unlikely to suppress key landscape pests |
| Washington State University | Contribution usually less than their reputation |
| Colorado State University | Can be efficient, but ambush hunting limits the benefit |
| Penn State (eOrganic) | Suitable but general control in dense crops; will not give complete control of any pest |
| Ohio State | May not improve pest suppression, though releasing them does no harm |
| NC State Extension | Not useful for pest management; removes Chinese mantid egg cases from a pollinator garden |
Compiled by The Pest Control Brief from the extension publications named in the Sources list.
Note the split on the last two rows: Ohio State says releasing them does no harm, while NC State treats the Chinese mantis as a garden menace. Most commercially sold egg cases are Chinese mantis, according to Penn State, so buying them adds more of the introduced species. If you want more natural predators, the steps with better support are cutting back broad-spectrum sprays and leaving some dense planting, which help mantids and every other beneficial at once. Our guides to biological pest control and the evidence behind natural pest control cover which predators and products have trial data behind them.
Why are there praying mantis in my yard?
Because there is food and cover. Mantids settle where insects are plentiful, especially on flowering plants that draw pollinators, and in dense, unmown vegetation. Egg cases left on shrubs and perennials over winter hatch where they were laid, so a yard with mantids one year often has them the next. A mantis on a lit window or porch in late summer has often been drawn by the light, which Wisconsin extension notes attracts them at that time of year.
How to get rid of praying mantis?
In most homes there is nothing to get rid of. A mantis is not a household pest, does not breed indoors and does not damage plants or buildings. If one comes inside, coax it onto a sheet of card or into a cup and put it on a shrub outdoors. Spraying a mantis is never needed, and broad-spectrum sprays applied to kill one will also hit the pollinators covered in our guide to protecting pollinators from pesticides.
The one case for active control is the Chinese mantis in a pollinator or native-plant garden. NC State Extension’s approach is to cut off Chinese mantid egg cases between autumn and early spring, before they hatch, and destroy them; options it gives include cutting them in half and soaking them in water for a few days, or putting them out for woodpeckers and chickens. Identify each case first. The long, slender, grey-brown case with a pale midrib belongs to the native Carolina mantis and should be left alone. Our garden pest control guide covers what to do about the insects that are actually eating your plants.
Frequently asked questions
Are praying mantis dangerous?
Not to people or pets. Ohio State says mantids do not bite humans, and the University of Kentucky says they neither sting nor bite and are not normally considered pests. The risk runs the other way: mantids eat bees, butterflies and, occasionally, hummingbirds. A 2017 review found 147 recorded cases of mantids catching small birds, more than 70 per cent of them in the US.
Do praying mantis bite?
Extension entomologists at Ohio State and the University of Kentucky say mantids do not bite humans. They have chewing mouthparts and spined front legs built for holding insect prey, and no sting. Kentucky adds that they tend to stand still rather than fly off when approached. If you need to move one, let it walk onto a card or into a cup rather than grabbing it.
Is it illegal to kill a praying mantis?
No. The University of Kentucky calls this a widespread myth: praying mantids in the US are not endangered and are not protected by any specific law. Killing any animal can be illegal inside certain nature preserves and wildlife sanctuaries, which may be where the idea started. The native Carolina mantis is the state insect of South Carolina, according to Mississippi State University, but that title carries no protection.
How long do praying mantises live?
About one growing season for the active insect. Eggs laid in autumn overwinter in the egg case, nymphs hatch in late spring, and they moult several times before becoming winged adults in late summer. Wisconsin extension says adults die a few weeks after mating, and Washington State says the first frosts kill them off. Counting the months as an egg, the full cycle is about a year.
Are praying mantis good luck?
That is folklore, not biology. The name comes from the Greek “mantes”, meaning prophets, and the University of Kentucky notes a long history of religious and medicinal beliefs about mantids, including Chinese folk remedies made from egg cases, with no findings to support them. What a mantis in the yard does tell you is that there is plenty of insect prey and cover nearby.
Sources
- University of Kentucky Entomology, ENTFACT-418, Praying Mantids (Watkins and Bessin), revised 2026.
- University of Kentucky Entomology, Kentucky Critter Files: Praying Mantids (Newton), 2004.
- Ohio State University Extension, Ohioline ENT-67, Praying Mantids.
- Utah State University Extension, Beneficial Insects: Mantids (Hodgson and Patterson), 2007.
- University of Wisconsin-Madison Extension, Praying Mantids.
- UC Statewide IPM Program, Natural Enemies Gallery: Mantids, or Praying Mantises.
- NC State Extension, Growing Small Farms: Challenging the Conventional Wisdom About Praying Mantids (Roos), updated 2026.
- University of Illinois Extension, Home, Yard and Garden Pest Newsletter, Scouting Watch (Nixon), April 2003.
- University of Georgia Extension, Landscape Pest Management: Beneficial Insects, Mantids.
- Washington State University, HortSense fact sheet: Praying mantid.
- Colorado State University Extension, IPM Pests: Mantids.
- eOrganic, Praying Mantids (Lelito, Penn State University).
- Mississippi State University, Mississippi Entomological Museum fact sheet: Carolina Mantis, 2022.
- Bromley, S. W., Observations on the Chinese mantid, Bulletin of the Brooklyn Entomological Society 27: 196 onward, October 1932.
- Nyffeler, M., Maxwell, M. R. and Remsen, J. V., Bird predation by praying mantises: a global perspective, The Wilson Journal of Ornithology 129(2): 331 to 344, 2017; and University of Basel news release on the study, July 2017.
- The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026.
