The discovery of yellow-legged hornet nests in Auckland has raised alarms across New Zealand. With five confirmed detections so far, including two small nests found over a kilometer apart, experts fear there may be more lurking in the region. This invasive species poses a significant threat to public health, biodiversity, and the nation’s vital honey bee populations.
The yellow-legged hornet, scientifically known as Vespa velutina, first made its accidental debut in France in 2004. It quickly spread at a rate of approximately 100 kilometers per year, establishing itself across France by 2017. Now prevalent in Spain, Portugal, Germany, and other European countries, the hornet was first detected in the UK in 2016. Its potential range extends as far north as Scotland, suggesting it could thrive in New Zealand’s climate.
Understanding the Threat
Yellow-legged hornets are aggressive predators known for their ability to become highly abundant. In Europe, densities of up to 13 nests per square kilometer have been recorded, with some mature nests housing up to 13,000 individuals. This poses a direct threat to human safety and pollinator populations alike.
Impact on Human Health
The hornets’ stings can be deadly, with reports from Europe indicating they are a leading cause of anaphylaxis in some regions. Multiple stings can result in multi-organ failure, and there have been cases of eye injuries from venom sprayed through beekeeping visors. These incidents underscore the danger posed by the hornets’ aggressive nest defense behaviors.
Devastating Effects on Pollinators
Yellow-legged hornets have a diet that includes a significant proportion of honey bees. A European study found that 40% of their prey were honey bees, with the remainder consisting of flies and other pollinators. In high-pressure areas, beekeepers have reported losing up to 80% of their hives once the hornets establish themselves. Typical hive losses hover around 30%, prompting desperate control measures such as beekeepers using badminton rackets to swat hornets away from hive entrances.
One nest can consume around 11 kilograms of insects in a single season, severely impacting local ecosystems.
New Zealand’s Unique Vulnerability
New Zealand’s biodiversity is particularly vulnerable to wasp and hornet invasions, as native insects have not evolved alongside such predators. The country’s warm, temperate climate further exacerbates the risk, with New Zealand already holding the world record for the largest individual wasp nest at 3.7 meters long. If yellow-legged hornets establish themselves here, they could become widespread and highly damaging.
Quick action is essential for eradication. The United States successfully eliminated the giant Asian hornet through a dedicated program, and closer to home, German wasps were eradicated from the Chatham Islands. Spain temporarily celebrated the eradication of the yellow-legged hornet from Mallorca, although populations have since reappeared.
The Role of Citizen Science
Early detection and eradication efforts for invasive species often rely on citizen science. Public trapping and reporting of sightings have proven invaluable overseas. In New Zealand, engaging the public in these efforts could be crucial to success. Traps specifically designed for yellow-legged hornets are used in Europe, but homemade traps made from plastic bottles can also be effective.
New Zealand’s tradition of public vigilance and commitment to protecting biodiversity could be a major asset in combating this threat.
The Ministry of Primary Industries is encouraged to implement these trapping strategies, as the hornets are attracted to a variety of foods, including protein sources like fish or meat, and even beer. If any country can catch this hornet early, it is New Zealand.
The stakes are high, and the time to act is now. By mobilizing public awareness and utilizing proven strategies, New Zealand has a fighting chance to prevent the yellow-legged hornet from becoming a permanent and destructive part of its ecosystem.
