As winters become milder due to , insects normally found only in the tropics are starting to feel more at home across Europe. And the speed of travel and global trade is making it easier than ever for them to make the trip — in imported wood, potted plants or simply as stowaways.
But these exotic newcomers aren’t exactly welcome. Experts with the European Environment Agency told DW that , including insects, are a “major threat to native plants and animals in Europe and are one of the five major causes of loss.”
Though tiny, these pests compete with native species for resources and destabilize fragile ecosystems already dealing with pollution, overexploitation and the effects of a warming planet. They’re also a serious problem for humans, spreading disease, destroying crops and costing the EU an estimated €12 billion ($13.8 billion) per year in .
Here are just a few of the greatest invasive insects threatening Europe.
Asian tiger mosquito (Aedes albopictus)
The , named for its distinctive white stripes, is native to the tropical and subtropical forests of Southeast Asia and was first spotted in Albania in 1979.
It made its way over to Italy and France in the 1990s, and is now well-established across the Balkans, southern Ukraine, southwestern Russia and much of the Mediterranean region. But with its tough eggs and a new tolerance for cooler weather, it has also been spotted in Belgium, Germany and as far north as Sweden in recent years.
The tiger mosquito thrives in urban environments, reproducing in standing water in places like flowerpots or gutters. This adaptability — along with a tendency to be active during the day — has made humans an easy target for the insect, which can feed on blood several times a day.
Aside from being an itchy nuisance, those bites can transmit like , , West Nile and .
Asian hornet (Vespa velutina nigrithorax)
This stinging menace, originally from eastern Asia, first arrived in France in 2004. Also known as a yellow-legged hornet, it’s slightly smaller than the native European variety, has an overall darker coloring and is active during the day. It has since spread to more than a dozen European countries, including Spain, Portugal, Belgium, Italy, Germany and the UK.
It’s not to be confused with the , also known as the “murder hornet” for its dangerous sting.
Though being stung by the Asian hornet can be quite painful for humans, the greater risk is to and biodiversity, according to agricultural nonprofit CABI. The species preys on hundreds of crucial pollinators such as bumblebees, butterflies and flies. But its main target is the , which pollinates more than 80% of Europe’s crops and wild plants. A study published in the journal Science Of The Total Environment in March 2025 found that the hornet can kill up to 50 bees a day.
The Asian hornet is one of 88 species on the EU’s list of Invasive Alien Species of Union concern, which requires member states to prevent the spread of the insect and eradicate it wherever possible.
American ants (Solenopsis geminata, Solenopsis invicta, Solenopsis richteri, Wasmannia auropunctata)
Also on the EU’s most wanted list are four species of : the tropical fire ant, the red imported fire ant, the black imported fire ant and the little fire ant.
These tiny invaders were accidentally introduced from Central and South America, with the tropical fire ant first showing up in Europe as far back as the 1860s.
With its painful sting which can cause an allergic reaction, these species rapidly displace other native ant populations and disrupt ecosystems and with aggressive feeding habits.
A 2023 study at the Institute of Evolutionary Biology in Barcelona found that 7% of the European continent was a suitable habitat for the ant, and that’s likely to grow as climate change increases their habitable range. Half of Europe’s cities were already vulnerable to invasion — bad news, as these ants can also damage electrical equipment by chewing through wiring and causing short circuits.
Brown marmorated stink bug (Halyomorpha halys)
This extremely invasive pest from Asia is now widespread in France, Italy and Switzerland, but present across most of the continent. They are especially attracted to fruit, nuts and grapevines, but are just as happy munching on vegetables and other crops, like soy. In Italy, the stink bug caused an estimated €588 million in damage to fruit crops in 2019 alone.
Farmers have traditionally fought back with insecticides, but researchers are also considering a more environmentally friendly method — pitting the stink bug against its natural enemy.
The Samurai wasp (Trissolcus japonicus), another accidental introduction from Asia, is a parasite that lays its eggs inside the eggs of the brown marmorated stink bug. The wasp larvae feed on the stink bug egg, eventually killing it.
Some researchers have cautioned that relying on another foreign insect to handle the problem might end up causing more ecological disruption. But a 2023 study led by CABI found that the wasp appeared to have little impact on most native insect populations.
Asian longhorned beetle (Anoplophora glabripennis)
Listed among the 100 world’s worst invasive alien species by the International Union for Conservation of Nature, this beetle is a major threat to deciduous trees and shrubs.
Adults feed on leaves, stems and twigs while larvae burrow into the trunk, slowly killing a tree within a few years. , are especially vulnerable due to their proximity to ports; in the eastern US, where the beetle arrived in the 1990s, up to 35% of the trees in cities are at risk.
The insects are often introduced in wood packaging, and have been found in France, Germany, Italy, Switzerland and Poland. But their populations are not yet widely established, and some eradication campaigns have been successful.
Europe will have to learn to live with invasive species
“Invasive alien insects often appear more difficult to manage than invasive plants or larger animals: they are small, mobile, reproduce rapidly, have short life cycle and often go unnoticed until the damage is done,” said the EEA.
While it’s nearly impossible to completely eradicate an invasive insect species, the damage can be mitigated. Asian hornets have been kept at bay in some areas with special traps and by removing their nests, while researchers in Italy have recently used drones and to detect and monitor stink bugs. Other methods involve stopping the insect at the source, for example by treating wooden packing with heat before shipping to kill the longhorned beetle. In some cases, it’s as simple as clearing any standing water from your balcony or backyard, to stop the spread of mosquitoes.
But the experts stressed that insects weren’t necessarily any worse than other invasive plants and animals, noting that “each group — and each invasion case — comes with its own biological and ecological complexities.”
Edited by: Tamsin Walker
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