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Invasive Asian Hornets Threaten European Insect Populations and Agriculture
Recent research has raised alarms about the invasive Asian hornets, which are consuming a vast array of insect species across Europe. These hornets are known to target crucial pollinators, intensifying concerns among scientists regarding the already struggling native insect populations affected by agriculture, land-use changes, and environmental pollutants.
The study, which analyzed the gut contents of over 1,500 hornet larvae, provides fresh insights into the “extra threat” posed by this invasive species to local ecosystems. Researchers highlighted that a significant portion of the hornet’s diet consists of pollinators, with 43 out of the 50 most frequently observed species recognized as flower visitors, including essential pollinators for European crops.
The Asian hornet, scientifically known as the yellow-legged hornet, is originally from Southeast Asia. It was introduced to France around two decades ago, following its arrival in a shipment of pottery from China. Since then, it has rapidly expanded its territory across Europe.
This invasive species primarily preys on honeybees, capable of decimating bee populations by killing up to 50 individuals daily, which has resulted in severe impacts on bee colonies in France and Italy. The first sighting of the hornet in the UK occurred in 2016, and sightings have continued, with 44 confirmed instances in 2024, primarily concentrated in Kent and East Sussex.
Researchers from the University of Exeter employed advanced genetic techniques referred to as “deep sequencing” to investigate the species consumed by hornets in more than 1,500 larvae from 103 nests located in Jersey, France, Spain, and the UK.
The study revealed that a total of 1,449 distinct prey items were fed to hornet larvae, with over half (55%) identifiable as specific species. The prey included a diverse mix of flies, wasps, bees, butterflies, moths, and spiders, with honeybees, common wasps, and blowflies being the most prevalent.
While honeybees were a common target — detected in nearly every sample — the hornets displayed an opportunistic feeding behavior, consuming a variety of insects that are abundant in their surrounding environment. Notably, the honeybee, buff-tailed bumblebee, and red-tailed bumblebee, which are among Europe’s key crop pollinators, were also found within the frequently consumed prey.
Siffreya Pedersen, the lead author of the study, stated, “While it is known that Asian hornets prey on honeybees, the breadth of their diet had not been comprehensively investigated until now. Our findings indicate significant variation in their diet seasonally and geographically, demonstrating their adaptability as predators.”
Pedersen emphasized the importance of insects in ecosystem functioning, underscoring their roles in pollination, decomposition, and pest control. Given the ongoing decline of many insect species due to habitat loss and pollution, the widening presence of Asian hornets presents an additional challenge to their survival.
The findings are detailed in a publication in the journal Science Of The Total Environment.
Source
www.theguardian.com