Two species of large Asian praying mantises, Hierodula membranacea and Tenodera sinensis, are expanding their populations across Europe, raising concerns among scientists about their potential impact on local ecosystems. The spread of these non-native predators is reportedly aided by rising temperatures linked to climate change and increased urbanization, creating suitable habitats and facilitating their dispersal.

The presence of these invasive mantis species poses a documented threat to Europe's native wildlife, including crucial pollinator insects such as bees and butterflies, as well as small vertebrates like frogs, lizards, and even small birds. Their larger size and aggressive predatory behavior give them a competitive advantage over the smaller, native European praying mantis (Mantis religiosa) and other indigenous insectivores.

Hierodula membranacea, commonly known as the giant Asian mantis, has been observed in various European countries since the early 2000s, with its range steadily expanding northward. This species, native to parts of Asia, is characterized by its significant size, with females reaching up to 10 centimeters in length. Its adaptability to diverse environments, including urban green spaces and agricultural areas, contributes to its successful establishment in new regions.

Tenodera sinensis, or the Chinese mantis, represents a more recent arrival in some European territories but demonstrates similar invasive traits. While less widespread than Hierodula membranacea currently, its documented spread is a cause for vigilance. Both species are known to reproduce prolifically, laying oothecae (egg cases) that can contain hundreds of eggs, further accelerating their population growth and expansion.

Key details regarding their spread and impact include:

  • Geographic Expansion: Observations confirm their presence in several European countries, including Italy, France, Spain, Portugal, and Switzerland, with new sightings reported in other regions.
  • Ecological Competition: These large predators compete directly with native insectivorous species for food resources, potentially disrupting local food webs.
  • Prey Spectrum: Their diet is broad, encompassing a wide range of insects and small animals, including beneficial pollinators vital for agriculture and ecosystem health.
  • Facilitating Factors: Warmer temperatures extend their breeding season and survival rates, while human activities like transportation and trade inadvertently aid their dispersal, with egg cases sometimes hitchhiking on plants or goods.

Scientists emphasize the need for continued monitoring and research to fully understand the long-term ecological consequences of these invasive mantises. Accurate data on their distribution, population densities, and specific dietary impacts are crucial for developing informed strategies to manage their spread and mitigate potential harm to European biodiversity. The ongoing expansion highlights the complex challenges presented by invasive species in a changing global climate.