Asiatische Hornisse

The Asian Hornet: A Growing Threat

The Asian hornet (Vespa velutina), also known as the yellow-legged hornet, is an invasive insect originating from Southeast Asia. Introduced to Europe in the early 2000s, it has rapidly spread across the continent and is now a significant concern for beekeepers, ecologists, and the general public.

Identification

Asian hornets are easily distinguished from European hornets by their distinctive appearance. Key features include:

  • Dark brown or black thorax and abdomen: Except for the fourth abdominal segment, which is a bright yellow band.
  • Yellow tips on legs: Hence the name “yellow-legged hornet.”
  • Smaller size than European hornets: Workers typically measure around 25mm in length, while queens can reach 30mm.
  • Dark head with an orange face.

It’s crucial to differentiate Asian hornets from native insects like the European hornet and various species of wasps and bees. Misidentification can lead to unnecessary alarm and potentially harm beneficial insects.

Impact on Honeybees

The Asian hornet poses a serious threat to honeybee populations. They are highly effective predators, often hovering near beehives and ambushing returning bees. They capture bees in flight, dismember them, and feed the protein-rich thorax to their larvae. This predation has several detrimental effects:

  • Reduced bee foraging: Bees become afraid to leave the hive, limiting their ability to collect nectar and pollen.
  • Colony weakening: The constant predation stress weakens the colony, making it more susceptible to disease and starvation.
  • Colony collapse: In severe cases, persistent hornet attacks can lead to the complete collapse of honeybee colonies.

Beyond honeybees, Asian hornets also prey on other insects, including butterflies, hoverflies, and other pollinators, impacting biodiversity and ecosystem stability.

Nest Building and Lifecycle

Asian hornets build large nests, typically in tall trees, but also sometimes in bushes, sheds, or even underground. These nests can house thousands of individuals. The lifecycle begins in the spring when a queen emerges from hibernation and starts a new colony. The queen lays eggs that hatch into worker hornets, which then take over nest building and foraging. In late summer and autumn, the colony produces new queens and males, which mate before the original queen and workers die off. The new queens then hibernate to start the cycle again the following spring.

Control and Management

Controlling the spread of Asian hornets is a challenging task. Current strategies include:

  • Nest destruction: Locating and destroying nests is the most effective way to reduce hornet populations. This requires specialized equipment and expertise, and should only be carried out by trained professionals.
  • Trapping: Trapping can help reduce hornet numbers, particularly in areas with high infestations. However, it’s important to use traps that are selective to avoid catching beneficial insects.
  • Research and development: Ongoing research is focused on developing more effective and environmentally friendly control methods.

Early detection and rapid response are crucial for preventing further spread. Reporting suspected sightings of Asian hornets to local authorities or national bee health organizations is essential for effective monitoring and management.