As the Bee Biosecurity Officer for Queensland, I keep my eyes peeled for bee pests and diseases when I am undertaking demonstrations or hive checks. More importantly though, I educate beekeepers throughout Queensland on the pests and diseases that they should be looking for in their own hives and how to identify them. Asian hornets are one of the many important pests that beekeepers should be aware of.
The Asian hornet (Vespa velutina) is an exotic pest of bees that we don’t yet have in Australia. Adult hornets prey on adult and larval bees, reducing bee numbers and hive productivity. In some cases, wasp attacks can result in total collapse of the hive with reports of losses between 5 and 80% of hives.
It is important that beekeepers are aware of what the hornet looks like and report any potential sightings to their state department of agriculture or primary industry, or the Exotic Plant Pest Hotline (1800 084 881).
Originally found throughout Asia, Asian hornets have also been introduced to Europe where they have caused a decline in bee productivity and the loss of hives. If they are introduced into Australia, Asian hornets could have large impacts on our honey bee industry and environment.
Like bees, Asian hornets are a social species, with queens, drones and workers. The hornets often fly around the entrances of hives preying on adult bees or may enter hives to prey on adult and larval bees. In late summer, adults may also be found feeding on fruit and flowers, either alone or in groups.
Distinctive characteristics of Asian hornets include the bright yellow tips on their legs and a brown or black thorax. The fourth segment on the abdomen is yellow or orange, while the other segments are bordered with yellow or orange. In dark variants, the yellow segment can be harder to see. The different castes are different sizes, with queens 30-35 mm long and workers 25 mm long.
Asian hornets build distinctive nests. Early on, the nests may be quite small and look like cones filled with smaller cells. Unlike European hornets, the entrance to an Asian hornet nest is on the side, not the bottom of the nest. Large Asian hornet nests can be 60-90 cm tall and 40-70 cm wide. The nests are constructed with several layers of paper mache like material, and most Asian hornet nests are made up of 5-6 layers each 45 mm thick.
There are several species of wasps and hornets (both native and introduced to Australia) that look similar to Asian hornets. Potter wasps, European paper wasps and mason wasps all have similar colouring, however, they have yellow or orange patches on their thorax, while spider wasps lack the yellow or orange borders on their abdominal segments. The nests of European paper wasp can look similar, although they are smaller than Asian hornet nests and are fully enclosed in a paper envelope when complete, while the brood cells are visible in European paper wasp nests.
Remember, if you think you see an Asian hornet call your state department of agriculture or primary industry, or the Exotic Plant Pest Hotline (1800 084 881). If you can do so safely, capture or take a photograph of the wasp to assist biosecurity staff in identifying the pest.
Acknowledgement: This article was provided by Queensland Bee Biosecurity Officer Rebecca Laws.