Invasive Giant Resin Bee Spreads in Europe via Ornamental Trees 2026

The invasive giant resin bee (Megachile sculpturalis) is spreading in Europe, and new research shows that ornamental trees in urban gardens are inadvertently fueling its expansion. This is the first documented invasive bee in Europe, and its success is tied to the pollen of a non-native tree.

What Is the Giant Resin Bee?

The giant resin bee is native to Asia and was first detected in Europe in 2008. It is a large, robust bee that collects resin to build its nests, often in existing cavities. Unlike many bees, it is not a pollinator of native plants but rather a specialist on certain exotic species.

Its introduction to Europe is likely accidental, arriving via shipping containers or ornamental plant trade. Since then, it has spread rapidly across the continent, aided by the abundance of its preferred food source.

The Role of Ornamental Trees in Its Spread

A study by researchers at the Universitat Autònoma de Barcelona has found that the giant resin bee feeds almost exclusively on the pollen of the Japanese pagoda tree (Sophora japonica), also known as the Chinese scholar tree. This ornamental tree, native to China, was introduced to Europe in the 18th century and is now common in urban gardens and streets.

The tree's abundant pollen provides a reliable food source for the bee, allowing it to establish and thrive in new areas. Urban landscaping with such exotic trees creates ideal conditions for the bee's proliferation.

Why Urban Gardens Matter

Cities often host a high diversity of ornamental plants, many of which are non-native. These plants can support invasive species by providing resources that are scarce in natural habitats. The giant resin bee's reliance on the Japanese pagoda tree exemplifies how human choices in landscaping can have unintended ecological consequences.

Impacts on Native Ecosystems

The spread of the giant resin bee raises concerns for native bee populations. Although it is not aggressive toward humans, it may compete with native bees for nesting sites and floral resources. Its preference for exotic trees means it could disrupt local pollination networks.

Moreover, the bee's nesting habits—using resin to seal cavities—can damage wooden structures and potentially affect other cavity-nesting species.

• The giant resin bee is the first invasive bee documented in Europe.
• It feeds almost exclusively on the pollen of the Japanese pagoda tree, an ornamental species.
• Urban gardens with exotic trees facilitate its spread.
• Competition with native bees and potential structural damage are key concerns.
• Management strategies should consider landscaping choices to limit invasive species.

What the Research Shows

The study highlights the link between urban tree composition and invasive bee establishment. Researchers observed that areas with high densities of the Japanese pagoda tree had larger populations of the giant resin bee.

This finding underscores the importance of considering ecological impacts when designing urban green spaces. Simply planting exotic species for aesthetic reasons can have far-reaching effects. The background to this story is set out in Moscardón Bumblebee: Giant Patagonian Pollinator Faces Extinction. A related thread runs through Invasive Pheasants Now Dominate Argentina's Victoria Island Forests. Earlier coverage in Invasive Species in Spain: Why the Guadalquivir Is a Hotspot shows how the argument developed.

What to Watch Next

As the giant resin bee continues to spread, monitoring its distribution and impact will be crucial. Researchers recommend that urban planners and gardeners prioritize native tree species to reduce the risk of supporting invasive insects. A closer look at the same subject appears in Invasive Species Cost Australia Billions: How to Respond. Anyone following the wider picture can start with Invasive Species Cost Australia $24.5B: How to Respond. The same theme surfaces in Florida Python Challenge Winner Kills 96 Invasive Snakes, which takes a different angle.

Public awareness can also help: reporting sightings of the bee can aid in tracking its expansion. Understanding the role of ornamental plants in invasion ecology is essential for developing effective management strategies. Context on how this played out before sits in Giant Waterlily Discovery: New Species Found in Colombia. A companion piece, Non-Invasive Gel Cockroach Control: Odorless & Effective, approaches the same subject from another angle.

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