Several of the most common praying mantis species encountered in North America, Europe, and Australia are, in fact, non-native introductions, and growing evidence suggests some meet the ecological criteria for invasive species. The Chinese mantis (Tenodera sinensis) and the European mantis (Mantis religiosa) were brought to North America over a century ago, largely for pest control, and have since established permanent populations across much of the continent. Whether they qualify as “invasive” rather than simply “introduced” depends on the ecological harm they cause, and recent dietary studies paint a more troubling picture than many gardeners expect.
Native Versus Introduced Mantis Species
North America has roughly 20 native praying mantis species. The Carolina mantis (Stagmomantis carolina) and the bordered mantis (Stagmomantis limbata) are among the best known. These species evolved alongside local ecosystems and fill established predatory roles. But the mantises most people in the eastern United States actually encounter in their backyards are not native at all. The Chinese mantis, which can reach over four inches long, was introduced around 1896. The European mantis arrived around the same time, likely as a stowaway on nursery stock. Both species are now widespread, and both are commercially sold as egg cases for garden pest control.
Researchers studying behavioral differences between the European mantis and the native bordered mantis in areas where they overlap found that the two species are sympatric across much of their range, meaning they share the same habitat and compete for the same resources.1PubMed Central. Behavioral variation post-invasion: Resemblance in some, but not all, behavioral patterns among invasive and native praying mantids That overlap matters because introduced mantises tend to be physically larger than their native counterparts, giving them a size advantage in direct competition and even enabling them to eat native mantis species outright.
What Non-Native Mantises Actually Eat
The popular image of a praying mantis as a helpful garden predator that eats pest insects is only partly true. A detailed dietary analysis of Chinese mantises and European mantises in old-field habitats in Massachusetts found that these species form extensive links within native food webs, consuming arthropods from 22 different taxonomic orders. The majority of their diet, over 75%, consisted of herbivores, predators, and pollinators.2Food Webs. Diets of two non-native praying mantids (Tenodera sinensis and Mantis religiosa) show consumption of arthropods across all ecological roles In other words, these mantises do not discriminate between pests and beneficial insects. They eat whatever they can catch, including the bees, butterflies, and parasitoid wasps that gardens depend on.
The same study found that the most commonly detected prey group in the mantises’ diet was other mantises. Cannibalism and intraguild predation, where a predator eats other predators in the same community, are standard mantis behavior. When the non-native species doing the eating is larger than any native mantis sharing the habitat, the ecological consequences tilt heavily in one direction. Native mantis populations may decline not because they are outcompeted for food, but because they literally become food.
Modeling work has projected that at higher mantis densities, invertebrate communities suffer broad declines, with the greatest impacts falling on invertebrate predators, herbivores, and pollinators.3Biological Invasions. Standing on an invasion front: predicting potential impacts of praying mantids using fuzzy interaction webs This is not a surgical removal of pest species. It is a generalist predator reshaping the insect community from the top down.
Hummingbird Predation and Other Vertebrate Prey
One of the more startling findings in mantis research involves their predation on small birds. A global review documented 147 incidents of mantises capturing birds, spanning 13 countries and every continent except Antarctica. Twelve mantis species were recorded killing birds from 24 identified species. More than 70% of documented incidents occurred in the United States, where mantises were observed capturing hummingbirds attracted to feeders and nectar-producing plants in gardens. The ruby-throated hummingbird was the most frequently caught species.4The Wilson Journal of Ornithology. Bird Predation By Praying Mantises: A Global Perspective
Both native and non-native mantises were implicated in bird predation in North America, but the researchers specifically cautioned against using large non-native mantises in gardens for insect pest control. A Chinese mantis stationed near a hummingbird feeder is not just catching aphids. It is an ambush predator large enough to seize a bird by the skull and feed on it over the course of hours. This finding alone complicates the common advice to buy mantis egg cases for “natural” garden pest management.
The Garden Biocontrol Myth
Mantis egg cases, usually from the Chinese mantis, have been sold in garden supply catalogs and online for decades. The pitch is simple: release mantises in your garden, and they will eat the pests. The reality is more complicated. Mantises are generalist ambush predators. They do not preferentially target aphids or caterpillars over bees and butterflies. Their hunting strategy is to sit and wait for anything of appropriate size to wander within striking distance. That means a released mantis is just as likely to eat a beneficial pollinator, a parasitoid wasp that would have controlled pests for you, or another predatory insect as it is to eat an actual pest.
The dietary evidence described above confirms this. When researchers examined what non-native mantises in field settings actually consumed, the answer was everything: herbivores, predators, pollinators, parasitoids, and each other. A garden mantis may give you the satisfying feeling of biological pest control, but the net ecological effect may be neutral or even negative for your garden’s health. Encouraging native predator communities, planting for beneficial insects, and tolerating some pest damage often produce better long-term results than releasing a generalist predator that eats indiscriminately.
There is one context where mantis predation could play a useful role. Research on spotted lanternfly, an invasive pest spreading across the eastern United States, found that praying mantises are significant natural enemies of adult lanternflies in the pest’s native range in China. Researchers noted the potential for incorporating mantis predation into integrated pest management programs against this specific invasive pest.5PubMed. Predation efficiency of praying mantises as important natural enemies of spotted lanternfly, Lycorma delicatula Whether that translates to effective biocontrol in North American settings remains an open question, but it highlights the difference between targeted pest management research and the blanket “buy mantis eggs for your garden” advice found in retail catalogs.
Invasions Beyond North America
The question of mantis invasiveness is not limited to the Chinese and European mantises in North America. Non-native mantis species are turning up on multiple continents, and some are expanding rapidly. In France, citizen scientists documented the establishment of the Indochina mantis (Hierodula patellifera), a large Asian species not previously recorded there. Researchers noted that this species is more massive than any native French mantis and raised concerns about competition and ecological pressure on native mantid communities, drawing a parallel to the disruption caused by the Asian hornet in Europe. At the same time, they acknowledged that competitive effects like resource depletion and intraguild predation from such newcomers are considered “probably negligible” at current population levels, partly because Europe has relatively few mantis species to begin with due to historical Ice Age losses, which may leave empty ecological niches for newcomers to fill.6PubMed Central. When Citizen Science highlights alien invasive species in France: the case of Indochina mantis, Hierodula patellifera
In Australia, the South African mantis (Miomantis caffra) has been spreading across the mainland. Researchers used records from four different citizen science and social media platforms, combined with museum records, to track the species’ expansion through the country.7Journal of Orthoptera Research. Citizen scientists track a charismatic carnivore: Mapping the spread and impact of the South African Mantis (Miomantidae, Miomantis caffra) in Australia That study provided the first records of the species on the Australian mainland and illustrates how rapidly a non-native mantis can colonize new territory when conditions are favorable. The South African mantis had previously established populations in New Zealand, where it has been linked to declines in native mantis species through sexual cannibalism: female South African mantises lure males of native species, mate with them, and eat them, producing no viable offspring. The native males are essentially removed from the breeding population.
Climate Change Is Expanding Mantis Ranges
Warming temperatures are accelerating the spread of both native and non-native mantis species into regions where they previously could not survive. A study of the Asian mantis Hierodula patellifera in South Korea found that the species’ distribution range had expanded toward higher latitudes and inland regions over the preceding 40 years. Species distribution models identified temperature-related variables in summer and winter as the most critical factors driving that expansion.8Journal of Asia-Pacific Entomology. Climate warming induces the activity period prolongation and distribution range expansion of the Asian mantis Hierodula patellifera in South Korea As winters become milder, egg cases that would previously have been killed by cold can survive, allowing populations to persist at latitudes that were once too far north.
Similar dynamics have been documented in Europe, where the European mantis Mantis religiosa has been expanding its range northward in Germany in response to climate and landscape changes.9Johannes Gutenberg-Universität Mainz. Ausbreitung und Etablierung der Europäischen Gottesanbeterin “Mantis religiosa” in Deutschland unter dem Einfluss des Klima- und Landschaftswandels Mantis religiosa is a heat-loving species, and warming temperatures have allowed it to establish in areas of northern Germany where it was previously absent. This is a case where a species that is native to southern Europe becomes a novel arrival in ecosystems further north, raising some of the same questions about ecological disruption that apply to fully non-native introductions elsewhere.
For non-native mantises already established in North America, climate change is likely to expand the zones where they can overwinter successfully. The Chinese mantis, for example, is currently limited in its northern range by winter temperatures that kill its egg cases. As those thermal boundaries shift, the species could push further into Canada and into higher-elevation habitats where it has not previously persisted.
Why the “Invasive” Label Is Complicated
Not every introduced species is considered invasive. The distinction matters because “invasive” implies measurable ecological or economic harm, not just the presence of a non-native organism in a new place. The Chinese mantis and the European mantis have been in North America for well over a century, and for most of that time they were viewed as benign or even beneficial. It is only in recent decades, as dietary analyses and ecological studies have become more sophisticated, that the picture has shifted.
The evidence for ecological harm is now substantial. Non-native mantises consume pollinators and parasitoid wasps at high rates, prey on hummingbirds, and may suppress native mantis populations through direct predation.2Food Webs. Diets of two non-native praying mantids (Tenodera sinensis and Mantis religiosa) show consumption of arthropods across all ecological roles Modeling suggests these effects intensify as mantis density increases.3Biological Invasions. Standing on an invasion front: predicting potential impacts of praying mantids using fuzzy interaction webs Whether regulators formally classify these species as “invasive” is partly a policy question, not just a scientific one. Some states still allow the sale of Chinese mantis egg cases, and no federal restrictions exist on their distribution. The gap between what entomologists are finding and what retail garden catalogs recommend is wide, and it has been slow to close.
In Europe, the situation is different. Some mantis species newly arriving in the region face ecosystems with fewer native mantises to compete with, and researchers have noted that Europe’s mantis communities are relatively depauperate compared to structurally similar habitats in Africa and Asia, a legacy of past glaciations. The introduction of a new large mantis may fill an empty niche rather than displace an existing species, at least initially. Whether that changes as populations grow and overlap with native species remains to be seen.
Citizen Science and Tracking the Spread
One practical development in understanding mantis invasions is the growing role of citizen science. Non-native mantises are large, conspicuous, and charismatic enough that members of the public notice and photograph them. Platforms like iNaturalist have turned casual observations into usable distribution data. The tracking of the South African mantis across Australia relied heavily on citizen science and social media records alongside traditional museum specimens.7Journal of Orthoptera Research. Citizen scientists track a charismatic carnivore: Mapping the spread and impact of the South African Mantis (Miomantidae, Miomantis caffra) in Australia Similarly, the first records of the Indochina mantis establishing in France came through citizen observations.6PubMed Central. When Citizen Science highlights alien invasive species in France: the case of Indochina mantis, Hierodula patellifera
If you find a mantis in your yard and want to know whether it is native or introduced, size is a reasonable first clue. In the eastern United States, the Carolina mantis tops out at about two and a half inches and is typically mottled green or brown. The Chinese mantis is often over three inches, sometimes four, and tends to be a more uniform tan or green with a distinctive stripe along the edge of its wing covers. The European mantis is slightly smaller than the Chinese mantis but larger than most native species, and it has a distinctive black-ringed spot on the inside of its front legs. Photographing the specimen and uploading it to a platform like iNaturalist helps researchers map distribution changes in real time, which is one of the few tools available for tracking how these populations shift year to year.
What Happens to the Egg Cases
Mantis egg cases, called oothecae, are a key part of the population dynamics of both native and introduced species. A female mantis deposits her eggs in a frothy mass that hardens into a protective shell, typically attached to a twig, fence post, or building wall. Each ootheca can contain dozens to hundreds of eggs depending on the species. The Chinese mantis produces some of the largest egg cases, sometimes containing over 200 eggs.
These egg cases are not invulnerable. Parasitoid wasps in the genus Podagrion specialize in attacking mantis oothecae, drilling through the hardened shell to lay their own eggs inside. Research on native bordered mantises in Arizona found that the likelihood of an egg case being parasitized was higher in areas with dense mantis populations. Experimentally reducing egg case density lowered parasitism rates, suggesting that parasitoid wasps are density-dependent in their search patterns.10Population Ecology. Contrasting scales of oviposition and parasitism in praying mantids For introduced mantis species, the question is whether native parasitoids can effectively regulate their populations. If the non-native mantis encounters fewer specialist enemies in its new range, its egg cases may survive at higher rates than those of native species, giving it yet another competitive edge. The degree to which native parasitoids have adapted to attack non-native mantis oothecae remains poorly studied, and it is one of the gaps that makes predicting the long-term trajectory of these introductions difficult.