At the end of last month (on 28th August) I sat on a hillside in Galicia, Spain, next to a beautiful bush of flowering bell heather, photographing the wasps which were gorging themselves on the pollen and nectar. They were covered in pollen (below).
They were very calm and non-aggressive and I sat right next to them for some time. I did not realise at they time that I was photographing the Asian hornet or yellow-legged hornet (Vespa velutina), and not a native species.
The site was near a beautiful lookout point called Mirador do Miranda en Cariño above the town of Cariño (below).
It was only when I saw the impressive nest of this invasive species in the local museum in Ortigueira, did I realise that I had been watching the Asian hornet.
There are many different subspecies of Vespa velutina in Asia but the one that invaded Europe in 2004 and is spreading through France and Spain, is Vespa velutina nigrithorax. (1, 2). This wasp is actually smaller than the European hornet Vespa crabro, but it is a major threat to European honey bees (Apis mellifera), which unlike Asian honey bees (Apis cerana) – which evolved in the presence of this predator – do not have any defense against the Asian hornet. Our poor bees do not know how to cope with an attack by the Asian hornet. Unlike the Asian honeybees, which make a ‘very fast bee-line for the hive entrance to avoid the jinking wasps’, poor old A. mellifera ‘slows down and sashays in the face of wasps.’ (3) And although our honey bees can kill native predatory hornets by ‘heat-balling’ – surrounding them in a mass of bees – they fail to kill the Asian hornets. The Asian honey bees have ‘learnt’ how (evolved a way) to do so using a temperature higher than A. mellifera and with more balling bees. (4)
This insect was first detected in Galicia in 2013 and appears to have significantly spread and colonized new areas in the past few years. It is reassuring to see that much is being done to try to minimize the impact of this pest and there is some excellent information available online (in Spanish) including a pest management programme. (5) The widespread presence of the Asian hornet in this area is however, very worrying.
It seems that the pest is now very well established in northern Spain and is surely impossible to eradicate. In South Korea, where V. velutina also invaded and is now well established, it has rapidly displaced native hornets and become the dominant species in urban areas. (6). That is a very worrying prospect for European countries and a lot of work needs to be done, especially on the ecological effects on native species, as this Asian hornet feeds very wide range of insects, including flies, dragonflies and grasshoppers. It is really quite concerning, not just for honey bees, whose hives can be protected – by reducing the hive entrance to a narrow slit – to keep out the invasive hornet, but for native insect species.
There are some fantastic pictures of Asian hornets attacking a bee hive on this site called The Bee photographer (7).
- Monceau, K., Bonnard, O., & Thiéry, D. (2014). Vespa velutina: a new invasive predator of honeybees in Europe. Journal of pest science, 87(1), 1-16.
- Tan, K., Radloff, S. E., Li, J. J., Hepburn, H. R., Yang, M. X., Zhang, L. J., & Neumann, P. (2007). Bee-hawking by the wasp, Vespa velutina, on the honeybees Apis cerana and A. mellifera. Naturwissenschaften, 94(6), 469-472.
- Tan, K., Wang, Z., Li, H., Yang, S., Hu, Z., Kastberger, G., & Oldroyd, B. P. (2012). An ‘I see you’prey–predator signal between the Asian honeybee, Apis cerana, and the hornet, Vespa velutina. Animal Behaviour, 83(4), 879-882.
- Choi, M. B., Martin, S. J., & Lee, J. W. (2012). Distribution, spread, and impact of the invasive hornet Vespa velutina in South Korea. Journal of Asia-Pacific Entomology, 15(3), 473-477.