Praying mantises have fascinated people for centuries. Across different cultures, they have been seen as everything from mystical guides who help lost travelers find their way home to creepy creatures associated with bad luck. Beyond legend, native praying mantises also play an important ecological role as indicators of healthy and biodiverse ecosystems.
But now scientists say two Asian praying mantis species pose a growing threat to Europe’s native wildlife.
Asian giant praying mantis officially classified as an invasive species
New research published in open access Orthoptera Research Journal Two species of praying mantises discovered in Europe have been officially designated. Hierodura tenuidentata and Hierodura pateriferaas an invasive alien species (IAS). The decision follows a study led by Roberto Battiston of the Museum of Archeology and Natural Sciences G. Zanato, which investigated how these Asian native species influence European ecosystems, an issue that has so far received little scientific attention.
Battiston said the insect has been present in Europe for about a decade, but its population has increased dramatically in recent years across the Mediterranean and continental regions.
“Thanks to climate change, they are moving further and further north,” Battiston explained, adding that established populations in parks and gardens are regularly reported by the public. Because these praying mantises are large and impressive in appearance, many people consider them a welcome sight rather than a potential ecological problem.
“This research was born to give people those answers and develop strategies to contain them.”
Why do praying mantises spread so quickly?
both Hierodura tenuidentata and Hierodura paterifera They are large, adaptable predators that spend much of their time in trees and shrubs. They also reproduce at an abnormal rate. Each egg case can produce an average of about 200 young, which is almost twice as many as the native European praying mantis (religious praying mantis). Young nymphs are also less likely to cannibalize, so their population can increase rapidly.
Their success poses serious challenges to native wildlife. Female non-native species attract native male praying mantises, who attempt to mate with them but end up being eaten, reducing the local population. They also feed on a wide range of native animals, including important pollinators such as honeybees and protected small vertebrates such as tree frogs and lizards.
The researchers say these impacts make it especially important to assess the risk on Mediterranean islands, which are home to many unique invertebrate and vertebrate species found nowhere else.
Cats, cities, and climate change
One surprising finding is that domestic cats are the main vertebrate predators of these invasive praying mantises, accounting for 45% of the positive predation events recorded.
Battiston points out that while cats can help reduce the number of invasive praying mantises, they can’t tell the difference between invasive and native species. Free-roaming cats also prey on the European praying mantis, which is already under pressure from competition from invasive newcomers and is declining in many peri-urban environments.
Human development is also driving the expansion of insects. Urban and suburban landscapes provide ideal conditions; Hierodura Praying mantises use structures such as insect hotels as productive hunting grounds. Urban heat islands help maintain activity late in the cold season, extending both survival and geographic range beyond normal possibilities.
Citizen science can help slow the spread of infection
To better understand these invasive praying mantises and limit their spread, researchers turned to the general public.
“My colleagues William Di Pietro and Antonio Fasano (GRIO) have launched a large-scale citizen science project and have successfully collected over 2,300 reports from enthusiasts and citizens. Citizen science is a fundamental tool not only for monitoring, but also for raising awareness and informing people about these issues in an active and participatory way.”
Scientists say people can do more than just report sightings. During the winter, when trees and shrubs lose their leaves, the insect’s ootheca, a brown, spongy egg case about 2-3 cm long, can easily be found on the branches. Egg cases can be removed without pain, but Battiston emphasizes that you should consult an expert first to avoid accidentally removing native praying mantis eggs.
Protecting Europe’s unique biodiversity
The spread of these Asian praying mantises highlights how human activity and climate change can alter the natural boundaries that once restricted invasive species. As these adaptable predators continue to spread across Europe, public awareness, citizen science and carefully targeted conservation efforts are essential to protect the continent’s unique biodiversity, researchers say.
