The Asian hornet comes to Britain14 min read . Updated: 01 Jan 2017, 12:25 AM IST
While the rushes to warn the public, the real threat of the invading Asian hornet in Europe is left out of the story
While the rushes to warn the public, the real threat of the invading Asian hornet in Europe is left out of the story
In 2004 a ship carrying Chinese pottery docked at the port in Bordeaux, France. It is now generally believed that within the packing material used to ship the Chinese goods were a number of “hibernating founding females" of the species Vespa velutina, or the Asian hornet.
The V. velutina females were stowaways who suddenly found themselves hundreds of miles from home in a foreign land that, by some remarkable coincidence, was not particularly inhospitable. As experts later noted, the weather in much of France is not all that dissimilar to the cooler mountainous regions of China that is home to V. velutina and many other hornet species.
At some point, perhaps as the weather warmed in early 2005, the hornets in Bordeaux emerged from their logistical cocoons and did what hibernating founding females do. They woke up, they reproduced and they generated colonies. And they did this in comfortable secrecy. After all there were other homegrown hornets in the region.
While the Asian Hornet has a distinctive yellow band across its belly, it is unlikely that many people in the south-west of France paid attention. But their cover was soon blown. In November 2005, the National Museum of Natural History in Paris reported that they had identified some specimens of a strange new hornet sent to them by an inhabitant of Lot-et-Garonne, less than a two-hour drive from Bordeaux on the A62 autoroute.
The news drove the French into apoplexy.
The Asian hornet, it turns out, is a very, very unpleasant insect.
It was not so long ago that human beings—in this case, Americans—lost their minds over another insect: the “Africanized killer bee". In 1978 Michael Caine starred as Dr Bradford Crane in Irwin Allen’s The Swarm. Caine plays an entomologist who helps an assortment of American celluloid good guys battle an “impossibly large, immeasurably powerful" swarm of killer bees that wreak havoc across America, one city at a time.
The eponymous swarm not only derails a train, but also sets off a nuclear explosion. It was ’70s cinemascope schlock of the highest quality. One trailer ends with the lines: “This is not speculation. This is prediction."
The Swarm perhaps marked the high watermark of the “killer bee" panic that swept across America in the late 1970s and early 1980s before culminating in cultural artefact.
In the 1950s, Africanized bees first began to appear in South America after several African queens escaped from a laboratory near Sao Paolo. The queens had been imported into Brazil to see if they could be used to make hybrids with local bee varieties. The hope was that the hybrid bee would bring some of the hardiness and higher yield of the African variety to Brazilian apiaries.
The queens that escaped began to mate with local drones creating an “Africanized" bee that was hardy and produced more honey, but also proved to be much more aggressive. The Africanized bees swarmed in larger numbers than native varieties, but were also more prone to attack intruders near their hives, and to chase them over long distances.
For twenty years the Africanized bees slowly spread their way northwards, through South and Central America, ever closer to the US border. Experts soon began to warn Americans of impending swarms of African “killer bees". Mass media and television news channels lapped it all up. Visions were manufactured and broadcast of American towns and cities laid waste by millions of the vicious insect intruders.
Things did not quite come to pass like that. Indeed Caine’s The Swarm predated the first permanent colony of Africanized bees in the US by over a decade. It was only in 1990 that the first major colonies crossed the border from Mexico and settled in Hidalgo, Texas. Since then, the species has gradually spread into the southern and southwestern US, and in many cases substantially replaced local varieties of bees.
While one or two deaths are attributed to the bees each year in the US, the apian overthrow of the greatest nation on earth is yet to take place. Americans themselves are working on that.
While the authorities remain vigilant—the University of Florida has a detailed African bee response plan on its website—the panic itself has passed into popular culture. Indeed Hidalgo later marketed itself as the “Killer Bee Capital of the World", complete with large bee statue and at least one local minor league sports team named the Killer Bees.
Why was the American public, in so far as was reflected in mass media, so consumed by these bees? Several researchers have tried to explain the killer bee hysteria, and other such mass hysteric outbursts, as a reflection of contemporary American anxieties.
In 2001 Mikel J. Koven of the University of Wales analysed three media products—two films and one novel—all about killer bees in a paper titled ‘Buzz off!’: The Killer Bee Movie as Modern Belief Narrative.
He found that The Bees, a novel by Jack Laflin released in 1975, “reflects a variety of anxieties of the post-Watergate America: that big businesses operate outside the law and are creating health risks for the public, that government officials are often corrupt and pilfer funding, resulting in ecological disasters because of insufficient equipment, and even anxiety about urban living and crime".
But in Caine’s 1978 The Swarm, Koven found reflections of another anxiety: that of an invading foreign army with little respect for traditional American values. These invaders, who Koven saw as representations of both the Vietcong and African-Americans, could only be repulsed with the help of the American military, a force then smarting from reversals in Vietnam. Many years later, in his Bowling for Columbine, Michael Moore used clips of the killer bee media hysteria to hint at the racial underpinnings of America’s obsession with guns.
The invading insect, then, evokes so much fear because it threatens many different types of equilibria.
The invading insect threatens the lives of native insects who are seen as benign and useful. The invading insect threatens to upset the equilibrium prevailing between local populations and the local environment. The invading insect threatens to disrupt local economies by undermining local flora and fauna. The invading insect threatens to contaminate local species by interbreeding with them and making them more aggressive and less docile.
And, perhaps most hysterical of all, the invading insect threatens to not only annihilate local species but also attack locals themselves.
Thus the threat of an invading insect, feeding off a popular and political culture of fear and sensation, can quickly transform into an existential, national threat that begins to sounds a lot like anti-immigrant, racist xenophobia.
On 6 September 2013, around a decade after it was first identified in France, the BBC’s Today radio programme asked listeners to keep an eye out for the Vespa velutina: “Because it was probably up to no good." Swarms of vicious Asian hornets, the show said, were preparing to cross the channel in hordes.
A guest on the programme, representing the British Beekeepers Association, spoke in a grave tone about what sounded like impending doom. Asking the hornets to stay in France, he said, was as futile as King Canute asking the tides to stay back.
The guest then went on to describe the hornet itself in vague terms, thus making it nearly impossible for most listeners to identify any. He also seemed confused about the hornet’s attacking mechanism against bees.
The Asian hornet ravaged honeybee hives, the guest said, because while the bee could only sting once before dying, the hornet could sting over and over again. Thus it was entirely possible for the Asian hornet to blitz through local British honeybee populations.
While much about the entire four-minute BBC radio segment is misleading, it got one thing absolutely correct. V. velutina is bad news for bees. But the hornet didn’t sting them to death before ravaging their hives. It had an entirely more direct strategy to deal with honeybees: it ripped their heads off.
Human beings often get entirely justified flak for wiping out species from the face of the planet. But introducing a non-native species into a new ecosystem in which the species suddenly thrives is one of the other foremost ways in which human beings have destroyed the environment they live in.
Over the centuries, humans have both intentionally and inadvertently introduced species into new environments only to see the guest wreak unremitted havoc. Often this happens in utterly unforeseen ways.
The bird called the starling is mentioned exactly once by William Shakespeare in all of his works, in a line in Henry IV, Part I. But that was plenty for Eugene Schieffelin, an eccentric pharmacist from New York in the late 19th century.
It is said, in what maybe an apocryphal story, that Shieffelin became obsessed with introducing every bird species mentioned in Shakespeare into the US. Almost all of these attempts—with birds such as the nightingale—failed.
An initial release of five dozen starlings into New York’s Central Park in 1890 also seemed abortive. So, the next year, Shieffelin released another 40 birds. This was all part of a broader trend, in vogue at the time, in which Americans and Europeans sought to propagate species across continents, in the hope of enriching diversity. These were all, in fact, just tremendously hubristic acts of ecological vandalism.
Shieffelin’s starlings propagated in huge numbers. In 1990, to mark the centenary of the starling’s introduction, The New York Times wrote that the bird has “has distinguished itself as one of the costliest and most noxious birds on our continent".
“Roosting in hordes of up to a million, starlings can devour vast stores of seed and fruit, offsetting whatever benefit they confer by eating insects. In a single day, a cloud of omnivorous starlings can gobble up 20 tons of potatoes.
“What they don’t eat they defile with droppings. They are linked to numerous diseases, including histoplasmosis, a fungal lung ailment that afflicts agricultural workers; toxoplasmosis, especially dangerous to pregnant women, and Newcastle disease, which kills poultry. Starlings bully several native species, often rudely evicting bluebirds and woodpeckers.
“In 1960 a Lockheed Electra plummeted seconds after taking off from Logan Airport in Boston, killing 62 people. Some 10,000 starlings had flown straight into the plane, crippling its engines. Any bird in the wrong place can pose such a danger, but it is the ever-present starling that pilots fret over the most."
In 2014 the BBC reported that the starling cost the US economy a billion dollars a year in crop damage alone.
The remarkable thing about the chaos unleashed by introduced species is that you can never really tell how this chaos is going to take place. Will the species attack a local species? Will it displace it from nests and breeding areas? Will it consume so much of a particular source of food that it starves another species?
Or, like the Asian hornet, will it pose local bees with a “military" challenge that it has never before seen?
The Asian hornet, a carnivore that will eat a variety of insects, has a simple strategy when it comes to attacking honeybee hives. The hornets will hover near a hive, waiting for bees to return from foraging, and then strike the individuals in the air, often decapitating them.
As the hornet carries the body back to the nest, it is replaced by another preying hornet. Waves after waves of such attacks weaken the hive and its guard bees, at which point hornets can often attack en masse to finish off any final resistance.
These attacks can be brutal, with each hornet capable of destroying as many as 40 bees a minute. A handful of Asian hornets can wipe out an entire hive of thousands of bees.
This raises the question: how do honeybees that share a habitat with the Asian hornet—a swathe of South and South-East Asia from northern India and Pakistan through China to Malaysia and other nearby islands—cope?
It is in the answer to this question that the real threat posed by the Asian hornet to the environment in Western Europe in general, and the UK in particular, becomes apparent.
For the sake of simplicity, let us focus on two of the most common species of honeybees: Apis mellifera, the European honeybee, and Apis cerana, the bee commonly found in South and South-East Asia.
Scientists are still not entirely sure about the details, but the general consensus is that Apis cerana has two main techniques of dealing with predators such as the V. velutina, both utterly fascinating.
The first is a thermal defence. Here, hundreds of Apis cerana bees surround the attacking hornet in a tight ball. They then begin to vibrate their bodies and/or flap their wings. This raises the temperature of the ball to between 47 and 50 degrees Celsius. This is just hot enough to kill the hornet, but still cool enough to keep the bees alive.
Some researchers also believe that the ball leads to a concentration of carbon dioxide that suffocates the hornet. It also possible that hornet is being poisoned by honeybee secretions. In any case, some combination of these three effects is enough neutralize the hornet.
The second technique, understood even less, is wing shimmering. Here, the bees form a wall of bodies in front of the hive and then move their wings in a manner reminiscent of spectators in a stadium executing a Mexican wave. The effect, a sequence of shimmering patterns, seems to confuse hornets somehow, who fly away without attacking the hive.
Thus through a combination of thermal ball-ing and wing shimmering, Apis cerana bees in South and South-East Asia have learnt to check the marauding tendencies of the V. velutina. But the situation is very different in Europe, where local honeybees have never had to deal with a predator like the Asian hornet till just over a decade ago.
Apis mellifera bees don’t have the same defensive abilities as Apis cerana hives. While they do form balls surrounding attacking wasps, the temperatures generated inside appear to be insufficient to neutralize the Asian hornet. Secondly, the European bees don’t show any knowledge of wing shimmering.
Thus, the inadvertent introduction of V. velutina into Europe poses a severe challenge to local honeybee species. (An interesting counterpart to this story is now taking place in Kashmir. Here, the Apis mellifera variety was introduced in the 1980s as a means to increase honey yields. However the same defensive frailties mentioned above means that the V. velutina has now become a serious pest that threatens the survival of the species in Kashmir.)
In contrast to the not inconsiderable media panic surrounding the Asian hornet’s threat to human health and life in the UK, the real threat from the species is to local honeybee varieties and hives. (Indeed at least one group of French researchers have strived to show that while the Asian hornet is perhaps more aggressive than other European wasps, it is not likely to attack human beings in much larger numbers.)
This is also why, over the past three years or so, the UK government has mobilized resources to keep a close eye on any Asian hornets on Britain, while continuously reiterating that the hornet is a threat to bees more than to people.
This has not stopped the media from milking all it can from this latest insect mini-hysteria. In October 2016, the Daily Mail ran with the headline: “Family tell of their terror after a two-inch ‘killer Asian HORNET’ flew into their kitchen forcing 10-year-old daughter to flee the house".
After months of waiting fitfully, in September 2016, almost three years to that first radio report on the BBC, the UK’s National Bee Unit confirmed that it had spotted the Asian hornet in Tetbury, Gloucestershire. The second line in the press release was: “The Asian hornet is smaller than our native hornet and poses no greater risk to human health than a bee. However, they do pose a risk to honeybees."
Investigators soon isolated a hornets’ nest in a tree. Some media outlets expressed alarm at the fact that the hive was only a few miles away from the Highgrove estate in Gloucestershire, where Prince Charles grows his own bees.
That this discovery did not spiral into a national media frenzy is perhaps thanks to the fact that there was little space left for headlines through the last few months of 2016 after the US presidential elections, misery in the Middle East and Brexit.
In November, the UK’s department for environment, food and rural affairs (DEFRA) announced that it had successfully contained the outbreak of Asian hornet in Gloucestershire. Since September, no more live sightings of the predator have taken place anywhere in Britain that we are aware of.
However the experts at DEFRA continue to call for vigilance and caution. After all, once the weather warms up again in 2017, the Asian hornet could wake up once more. In France, some experts have suggested that the hornet can propagate at the rate of 100km per year. And next time, Vespa velutina could find itself in a country full of defenceless bees, and a media ravenous for hysterical new headlines in the New Year.
That is not prediction, mind you, just speculation.