Amazing stuff!
"Asian hornets are formidable hunters, infamous for hanging around honeybee hives and plucking bees as they emerge. In some parts of Europe, where the hornets are invasive, beekeepers say they’ve killed up to half of their hives. ...
Now, a study finds these ruthless hymenopterans may not be such picky eaters after all. When researchers sampled DNA from hornet nests in France, Spain, and the U.K., they found roughly 1400 species of prey. “The diet varied strongly over the seasons and between regions, showing that they are highly flexible predators ,” ... Of the 50 species most frequently consumed, 43 are known pollinators, including some of the most important ones for European crops. ..."
"... researchers tested Asian hornet samples from France, Spain, Jersey and the UK throughout the hornet’s active season.
Eaten prey included a wide range of bees, wasps, flies, beetles, butterflies, moths and spiders.
Although the European honey bee was the most common species found in the hornets – appearing in all sampled nests and almost all larvae within those nests – their diet is a lot broader.
An invasive species, Asian hornets are now found in much of western Europe. Nests are destroyed in the UK mainland each year as authorities try to keep the species out. ...
“The diet varied strongly over the seasons and between regions, showing that they are highly flexible predators. ..."
From the highlights and abstract:
"Highlights
• A highly diverse range of invertebrates are predated on by Vespa velutina
• Considerable spatiotemporal dietary variation implies a highly flexible predator
• Apis mellifera is the most frequently predated species
• The functional groups most likely at risk are wild pollinators and decomposers
Abstract
Most terrestrial invertebrates are in considerable decline, and the range expansion of the invasive hornet, Vespa velutina nigrithorax, poses an additional threat. Although now found in much of western Europe, the full extent of the hornet's predatory activity remains unexplored.
While impacts on honey bees are well-documented, evidence of a wider dietary spectrum is emerging, indicating potentially broad ecological ramifications.
Here, we conduct the first large-scale study of the diet of V. velutina, utilising deep sequencing to characterise the larval gut contents of over 1500 samples from Jersey, France, Spain, and the UK.
Our results indicate that V. velutina is a highly flexible predator, enabling its continued range expansion capacity. Analyses detected 1449 taxa, with greater prey richness in samples from southern latitudes, and considerable spatiotemporal variation in dietary composition.
Hymenoptera, Diptera, Hemiptera, Coleoptera, Lepidoptera, and Araneae were the most frequently occurring orders predated, each characterised by high taxonomic diversity. The honey bee Apis mellifera was the most abundant species, being found in all sampled nests and showing greater relative read numbers with increasing apiary density and proximity, supporting concerns for the impact of V. velutina on apiculture.
Notably, 43 of the 50 most commonly predated invertebrates were also flower visitors, including 4 common bumblebee species, indicating potentially substantial risks to wild pollinators. These data provide wide and deep evidence to support risk evaluation of this species and its potential environmental impact as it spreads across Europe."
1,400 species found in guts of Asian hornets (original news release)
Broad ecological threats of an invasive hornet revealed through a deep sequencing approach (open access)
An Asian hornet dismembering a honey bee
Fig. 2. Overall diversity of taxa detected in the larval guts of V. velutina. The 1449 taxa across 26 orders are shown to family level for readability. Both node size and colour relate to the number of OTUs that were assigned to the displayed taxon.
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