According to the International Union for Conservation of Nature (IUCN, the people who publish the red list of threatened species),

And they are one of the biggest drivers of biodiversity loss and species extinctions.

The yellow-legged hornet is not merely a pest for beekeepers. It is a significant predator that triggers a cascade of effects, threatening the stability of local ecosystems. Its impact is twofold: a direct assault on pollinators and an indirect disruption of ecological balance.

The hornet’s specialized hunting strategy places immense pressure on honey bee colonies (Apis mellifera). This behavior, known as hawking, involves hornets hovering at the hive entrance, capturing returning forager bees in mid-air (source 1).

This constant predation has severe consequences. Bees become stressed and hesitant to leave the hive, leading to reduced food collection. The loss of foragers can weaken the colony, making it more susceptible to disease and potentially leading to collapse (source 2). For beekeepers and farmers, this results in significant economic losses.

The hornet’s threat extends far beyond honey bees. It is a highly efficient generalist predator, but its success lies in its remarkable adaptability. It shifts its hunting strategy based on local prey availability, making it a threat in virtually any environment (source 3, source 6).

A detailed study found its overall prey composition consists of honeybees (38.1%), flies (29.9%), and social wasps (19.7%), along with a wide spectrum of at least 159 different insect species (source 3).

New research confirms vast dietary range. A groundbreaking 2025 study using DNA analysis from over 1 500 hornet larvae across 103 nests in Europe revealed an even more comprehensive picture. Researchers identified 1 449 different species that had been fed to hornet larvae, with more than half (55%) identifiable to specific species (source 7). The prey included honeybees, common wasps, blowflies, butterflies, moths, and even spiders, confirming the hornet as a “highly flexible predator” whose diet varies strongly by season and region.

The scale of consumption is staggering. A single hornet nest can consume an average of 11.32 kg of insect biomass during one season (source 4). This represents a massive and novel pressure on local insect populations.

Analysis of nests from different habitats shows distinct feeding trends (6). In urban areas, its diet focuses heavily on honey bees. In agricultural zones, it shifts to include more flies. In forests, it preys more extensively on social wasps and other insects. 

This adaptability means that whether in a city, farmland, or a forest, the hornet finds a way to thrive, applying maximum pressure to the most available local insects.

The hornet’s impact reaches far beyond managed beehives, directly threatening the intricate web of life in our local ecosystems. Its massive consumption of insects creates a triple threat to native biodiversity.

By preying heavily on flies and other native insects, the hornet targets the very pollinators that wild plants and many crops depend on for reproduction. This includes wild bees and hoverflies that are essential for maintaining healthy plant communities.

As pollinator populations decline, essential pollination services are disrupted. This can lead to reduced seed and fruit production in both wildflowers and agricultural crops, potentially altering the composition of plant communities over time.

The hornet also competes with native insect-eating animals like birds and spiders for food. The removal of over 11 kilograms of insects from a single local area by just one nest represents a significant shift in the food web, potentially unbalancing established ecological relationships.

This isn’t just an environmental concern—it’s an economic one. Many crops rely on insect pollination, and declines in pollinator abundance can lead to lower yields and higher food costs. The yellow-legged hornet’s invasion therefore threatens both our natural heritage and our food security.