Madrid declares war on plague of racoon and parrot invaders

Chen pointed with a shaky hand at the small plot of cabbage, spring onions and corn where his friend, Yu Yihong, had been stung to death by giant hornets.

“When he got to the hospital, there were still two hornets in his trousers,” said Chen, a farmer who, like many villagers, declined to give his full name to a foreign journalist. “The hornets’ poison was too strong – his liver and kidneys failed, and he couldn’t urinate.”

Yu, a 40-year-old farmer in perfect health,, had been harvesting his crops when he stepped on a nest of Vespa mandarinia hornets concealed beneath a pile of dry corn husks. The hornets swarmed around Yu, stinging him through his long-sleeved shirt and trousers. He ran, but the hornets chased him, stinging his arms and legs, his head and neck.

After Yu succumbed to the poison about 50 of his friends and relatives gathered to mourn his passing. Outside the farmer’s mountainside home in Yuanba village, they ate buckwheat noodles and boiled peanuts in silence; one set off a string of fireworks. Yu’s wife and two children sat inside, weeping.

V mandarinia is the world’s largest hornet, around the size of a human adult’s thumb, yellow and black in colour and highly venomous. Its 6mm-long stingers carry a venom potent enough to dissolve human tissue. Victims may die of kidney failure or anaphylactic shock. Yu’s story is a tragic but increasingly common one in north-west China’s Shaanxi province, where, over the past three months alone, hornets have killed 41 people and injured a further 1,675.

Ankang, a municipality in the province’s south, appears to be the centre of the attacks. While hornets infest its mountainous areas every year – 36 residents were stung to death between 2002 and 2005 – local people and municipal officials say this year is tantamount to an epidemic, the worst they have ever seen.

At least some of the deaths were caused by V mandarinia, experts say. The species does not typically attack unless it feels its nest is threatened. The hornets can fly at 25mph and cover 50 miles in a day. They make their homes in tree stumps or underground, making nests extremely difficult to detect.

People blame this year’s scourge on climate change: the past year has been unusually warm, allowing a high number of hornets to survive the winter. Huang  Ronghui, an official at the Ankang Forestry Bureau’s pest control department, lists a host of other possibilities: the hornets may have been agitated by a dry spell, while labourers have been moving deeper into the mountains, disturbing their nests. “Other than this, hornets are attracted to bright colours and the smell of people’s sweat, alcohol and sweet things,” he told state media.

The region has also been overrun by the Asian hornet, Vespa velutina, a slightly smaller species which can be equally dangerous. Hundreds, even thousands, inhibit each nest, which typically hangs from a high place. In Chengxing village, a few miles down a winding mountain road from Yu’s home village, 16-year-old Tan Xingjian pointed at a tree. Hanging from one thick branch was a pale, basketball-sized bulb, its surface alive with darting black specks. “That’s where they live,” Tan said. “We don’t dare to near there.”

Ankang is on alert, with the local authorities posting warning notices online and on primary school walls. The crisis has exhausted Gong Zhenghong, the mayor of Hongshan township in rural Ankang. Since September, Gong has spent nearly every night wandering the township exterminating nests. He says there are 248 hornets’ nests in Hongshan, with 175 close to schools and roads.

Gong and his team survey nests by day; once the sun sets, they dress in homemade anti-hornet suits and burn the nests with spray-can flamethrowers. “They don’t fly around at night,” he said. “We’d normally send the fire squad to do this, but this year there were too many nests.” Gong left his office, returned with a black rubbish bag, and pulled out the charred remains of a nest, the blackened tails of bulb-like larvae protruding from its combs.

Two other cities in Shaanxi – Hanzhong and Shangluo – have been besieged by hornets, though the death tolls have been markedly lower. In southern China’s Guangxi Zhuang autonomous region, a swarm of hornets attacked a primary school in mid-September, injuring 23 children and seven adults. The teacher, Li Zhiqiang, tried to fight the creatures off until he lost consciousness, state media reported.

The hornets seem ubiquitous in Ankang. In Liushui township, a scattering of two-storey concrete homes, an elderly shopkeeper said the hornets had infested a cabbage patch near her home. “The government has been coming down and burning them, but they can’t burn them all,” she added, pointing down into the brush. “I’m not willing to go down there.”

Mu Conghui, a 55-year-old Ankang villager, was stung 200 times while tending to her rice field in late August. “These hornets are terrifying – all at once they flew to my head, and when I stopped, they stung me so much that I couldn’t budge,” she told state media. “My legs were crawling with hornets. Right now my legs are covered with sting holes – over the past two months I’ve received 13 dialysis treatments.”

The Ankang government says it has removed 710 hives and sent 7m Yuan (£707,000) to help affected areas. “We’re doing everything we can, but there’s only so much we can do,” says Deng Xianghong, the deputy head of the Ankang propaganda department. “God has been unfair to us.”

HEADING FOR BRITAIN?

Honeybees, hornets and wasps are all able to deliver painful and potentially lethal stings; but while bees are seen as doers of good, wasps and hornets have long been associated with evil.

Most deaths occur when a victim is stung repeatedly and injected with large amounts of venom. The hornet’s large size – and its ability, unlike honeybees, to sting multiple times – means that a victim can quickly receive a lethal dose.

One possible reason for the recent attacks in China may be increased encounters with the hornets nests, since multiple attacks usually occur when the insects defend their nests.

Hornets go through natural population cycles: in some years nests can be very common. Hornets are a top predator – the lions of the insect world – and depending on the species their nests can contain hundreds or thousands of female workers by the autumn (the males cannot sting).

So given the opportunity, a hornet population has a massive potential to expand rapidly, which has happened recently with the accidental introduction of the Asian hornet (Vespa velutina) to France and Korea.

Vespa velutina was accidentally introduced into France in 2003, where it has been responsible for a handful of deaths, and it has since spread to Spain, Portugal and Belgium. Britain is on high alert for its inevitable arrival.

Stephen Martin Professor Stephen J Martin is chair in social entomology at the school of environment and life sciences of the University of Salford.