British honeybees are being threatened by Asian hornets.
OVER the years, I have experienced many narrow escapes from bees, wasps and hornets.
As a child, I was often stung by bees and wasps and with a dab of bicarbonate of soda (alkali) on a bee sting and a dab of vinegar (acid) on a wasp sting, the respective acid and alkaline venoms were soon neutralised.
I distinctly remember two hiking holidays in the European Alps. Once in Austria, my young son took a sip from a can of coca cola to find a wasp inside his mouth. Inevitably it stung his tongue, which began to swell at a rapid rate.
Thanks to a nearby hotel, we stuffed his mouth with ice cubes and the swelling fortunately subsided saving his life from asphyxiation.
Another year, whilst trekking on a narrow, high mountain path, in the Slovenian Alps, we had no alternative, as dusk was falling, but to trample on a hornet’s nest in our efforts to quickly reach the valley bottom.
Covering our heads and faces with towels, yes, the hornets swarmed and chased us but luckily we escaped their fury without a single sting. Recently, in my house in the UK countryside, I caught a hornet. Two weeks later, in Kuching, I was buzzed by an identical hornet! It suddenly dawned on me that both hornets were Asian species.
Asian hornet
The Vespa velutina nigrithorax or yellow-legged hornet is the only species of hornet or wasp with an entirely dark brown or black velvety body, bordered with a fine yellow band and a black head and orange-yellow face. It can easily be confused with the European hornet (Vespa crabro), which is slightly larger than its Asian counterpart.
Asian hornets are never active at night, whereas the European hornet may well be. The former is predatory wasp. Queen hornets reach three centimetres in length and males about 2.5 centimetres. Worker hornets measure two centimetres.
Asian hornets feed in a field in France.
Distribution
As its name implies, it originates from Northern India, Pakistan, Afghanistan, Bhutan, China, Taiwan, Bangladesh, Myanmar, Thailand, Laos, Vietnam, Malaysia, and the surrounding archipelagos. More recently this invasive hornet has arrived in South Korea and Japan.
Its first appearance in Europe was related to a French import of boxed Chinese pottery in 2004. By 2009, there were several thousand nests in the Bordeaux area of South West France, and by 2015 the Asian hornet was seen in most of France. It spread to Northern Spain in 2010 and into Portugal in 2011. It moved eastwards into Italy in 2012.
Britain escaped this insect until July 2016 when it arrived in the Channel Islands, off the west coast of France and by September 2016 it was nesting in Gloucestershire, in the west of England. It is likely that its introduction to the UK was through soil associated with imported plants, cut flowers, fruit, garden furniture, plant pots, in freight-containers, or in/on imported timber. It is quite possible that it may have flown from France across the English Channel. Last September, it had arrived in Belgium.
Nesting habits
Each nest is made of paper in an ovoid shape of at least 0.5 metres in length and houses several thousand hornets, which moves in and out through a lateral entrance.
Initially, a nest is built in low shrubland but after a few months it is abandoned and re-established in a high tree. I well remember, in 2009, when I was principal of a Kuching school, spending break and lunch times ensuring that students kept well clear of such a large nest in one of the trees in the school grounds. Eventually it was destroyed at night by the school caretaker.
In Europe, these hornets are active from April to November but peak in August and September. The new, young queen hornets ‘winter over’, singly or in groups, underneath tree bark in cavities left by beetle larvae, or in soil, in ceramic plant pots or in nests built in garages, sheds, farmers’ barns or in house attics.
Photo of a destroyed Asian hornets’ nest.
Diet
The Asian hornet is an opportunist hunter, feeding on flies, dragonflies and other insects. In Southeast Asia, they usually hunt the eastern honeybee (Apis cerana).
These bees have adapted to the ever-present hovering (hawking) hornet by a lightning flash into and out of their hives. The hive’s ‘guard bees’ often ‘heat ball’ hornets to death by surrounding them in large numbers thus increasing the ambient temperature to a lethal 45 degrees Celsius. These hornets attack honeybees by biting off their heads.
Fortunately, they pose little risk to humans other than a wasp-like sting but multiple stings can, however, lead to anaphylactic shock. A few hornets can wipe out all bees in a hive in a few hours before they steal their honey.
Threat to British beekeepers
British honeybees (Apis mellifera) – the latter literally meaning honey bearing – have been on the decline for many decades principally owing to the destruction of wildflower meadows.
Farming has become more extensive and machine intensive, with ever-increasing greater usage of pesticides and herbicides to protect valuable crops. With a reduction of such valuable pollinators as bees, the number of wild flowers has decreased. That said, my garden, deep in the countryside is a buzz in summertime with bee and wasp activity collecting nectar from my flowering shrubs.
In the UK, the Department for Environment, Food and Rural Affairs is taking swift and robust measures to destroy these hornets’ nests on behalf of the British Beekeepers Association often using drones to spray the nests with insecticides.
Bee inspectors have been appointed to use infrared cameras to locate nests at night and to track hornets to their nests so that professional teams could quickly destroy them.
In France, a government-sponsored team has been attaching specially-designed tags to hornets to test tracking systems, using radio waves and radar. This system was invented by scientists at Exeter University, where a friend of mine, the late Dr David Stradling, was a senior lecturer in Zoology and an avid beekeeper.
Last September, a hornet was observed destroying beehives on the North Devon coast at Woolacombe, 60km from Exeter University.
Very recent research at the University of Warwick has predicted that these Asian hornets could create hundreds of thousands of nests across the UK by 2040 and future invasions from continental Europe are inevitable. The effect upon apiarists is obvious.
As for me, with ever increasing prices on a jar of honey, like Winnie the Pooh, I shall enjoy my breakfast of honey on toast as long as I can afford it.
Malaysian apiarists, I am sure, must know of tricks of the trade in preventing Asian hornet intrusions into their beehives.