A study reveals that Asian hornets feed on more than 1,400 insect species, including many essential pollinators. This discovery highlights the ecological impact of this invasive species, already feared for its attacks on honeybees.
Originating from Southeast Asia, Asian hornets (
Vespa velutina) have spread to Europe and North America, where they are considered an invasive species. Their diet, long thought to be centered on bees, turns out to be much more varied. A team of researchers from the University of Exeter analyzed the gut contents of over 1,500 hornet larvae, revealing an unexpected diversity of prey.
A surprising diet
The researchers used a method called deep sequencing to analyze the gut contents of Asian hornet larvae. This technique allows for repeated sequencing of a genome region, providing precise identification of the consumed species. Thanks to this approach, more than 1,400 species were detected, including bees, wasps, flies, butterflies, and even spiders.
The European honeybee remains the most frequent prey, present in all sampled nests. However, Asian hornets are opportunistic, adapting their diet to available resources depending on the season and region. This dietary flexibility partly explains their success as an invasive species.
Among the 50 most frequently identified prey species, 43 are flower visitors, including the three main European pollinators: the honeybee, the buff-tailed bumblebee, and the red-tailed bumblebee. These results, published in
Science of The Total Environment, underscore the extent of the threat to local ecosystems and pollination services.
A concerning ecological impact
Insects play a key role in ecosystems, particularly through pollination, decomposition, and pest regulation. The decline of insect populations, already weakened by pollution and habitat destruction, could worsen with the expansion of Asian hornets.
The researchers warn of the need to monitor and control this invasive species. Residents are encouraged to report nests to limit their spread.
To go further: Why are pollinators essential?
Pollinators, such as bees, bumblebees, and butterflies, play a crucial role in the reproduction of flowering plants. By transporting pollen from one flower to another, they enable fertilization and the production of fruits, vegetables, and seeds. Without them, many crops could not develop.
More than 75% of global agricultural crops depend, in part or entirely, on pollinators. Staple foods like apples, strawberries, tomatoes, and almonds are directly dependent on them. Their decline could therefore threaten food security and agricultural economies.
Beyond agriculture, pollinators support natural ecosystems by promoting plant diversity. This diversity is important for maintaining habitats for many animal species and for ensuring ecosystem services like climate regulation and water purification.
Their disappearance, accelerated by invasive species like Asian hornets, chemical pollution, and habitat destruction, would have dramatic consequences.
Article author: Cédric DEPOND