Barcelona draws the rifle (literally) against the Asian hornet, by Carles Cols

Imagine the scene. Three uniformed men in yellow vests cordon off a part of the Pegaso park with plastic tape. A poster hangs from the makeshift fence. ‘Danger. No passing. Wasps’. At the top of a classic Barcelona banana, thanks to the fact that it has lost enough leaves, it is possible to see a nest of Asian wasps the size of a basketball (the nest, not the wasps, clarification needed before you panic) . Lead the expedition, literally hunting, Jesús Jarque, biologist and sniper. That’s how it is. The team has left on the ground, two trees beyond, a portable refrigerator and a briefcase that, due to its dimensions, could well contain a pianist’s keyboard, but when opened. Oh, the sight of a rifle surprises everyone. With its telescopic sight and all. The ‘Vespa velutina’, wrongly baptized in its day by the press as the murderous wasp, is colonizing the streets of Barcelona with geometric progression since in 2018 it was seen for the first time in this city. That is already news, but it is even more so, given the weapons, the strategy that Barcelona uses in this war against the invader.

The Asian wasp has been talked about intermittently since 2004. It was then that it was supposed to have arrived in the south of France, it is not known how, a queen, bad news for European bees, that if they did not have enough problems already, they only lacked the threat of an enemy against whom they do not know, poor them, any combat technique, as their cousins ​​from the Far East have developed. The point is that the dynasty of that first queen there is no year that did not conquer new lands.

Came to Galicia in 2010. It soon acquired plague status in the Basque Country. The first nests sighted in Catalonia, in 2013, were in Girona’s forests. That one day he would dare with Barcelona was not a question of probability. It was a certainty. The surprising thing, perhaps, has been the ‘baby boom’ registered this year in the city, in which one day a nest is evicted in the Font d’en Fargues, another day the identical intervention is played in Arc de Triomf, shortly afterwards there is a colony of several hundred wasps on the dome of the Cathedral and, as happened last Tuesday , Someone has spotted a menacing Asian wasp home on the highest branch of a Pegasus tree, right next to the park’s giant slides octopus, which, by the way, gives the mission a ‘nosequé’ of ‘ Starship Troopers’ or, better yet, Sigourney Weaver versus Alien aboard the Nostromo ship.

In Galicia, nests, when possible, are attacked with fire. In France, Jarque says, they have even used explosives to contain the expansion. Poles are another fairly common option. Drones, as an option, are eye-catching. All this is trifle compared to the method used by Lokimica, the company that the Barcelona City Council, before the surprising departure of the Generalitat, administration responsible for combating invasive species, has hired to counterattack this already unquestionable problem. Frozen insecticide bullets. That’s the ammo. Pim pam, never so well said.

The strategy will sound crazy, but it is inexpensive (no forklift cranes) and, above all, extraordinarily effective. The secret lies in knowing the enemy. Asian wasps, like other species of the vespid family, have a clear protocol in case of aggression. A part of the workers of the colony leave the nest and look around for the aggressor. In the radius in which they search they do not find anything, so they return and join what the rest of their companions have already begun to do from the beginning, surround the nest, make a shield. It is their undoing. They are not ready for chemical warfare. Within a few minutes, some wasps plummet. Others fly awake through the park, as if they had just come out of an ‘after’. Most of those will die too. We are not talking about a simple human versus vespid skirmish. Inside a nest like that there are approximately 1,500 waspsJarque says from experience.

The rifle used, that must be clarified, does not come from an armory. It is a ‘paintball’ rifle retrofitted for the occasion. The propulsion of the bullets works with compressed air, but that does not detract from the excitement of the preparations, at that time in which Roddy Romero, in charge of shooting today, introduces the frozen bullets one by one into the curved magazine, which he grants to the rifle an air assault AK-47.

The operation is settled in just half an hour and with Prussian precision. Some of the bullets do not hit the nest, but those that do, the majority, penetrate to the depths of the superb architecture of the nest, a building of admirable resistance if one takes into account, as Jarque emphasizes, which is nothing more than natural papier-mâché made by the wasps themselves.

The operation, I said, is a success, but this is an end-of-season battle, more oriented to calm the most apprehensive who walk through the park than to contain the spread of the plague. In November and December the queens born in the nest, several dozen, have already left it and have sought refuge elsewhere to spend the winter. Not all of them will survive, but when spring arrives, the survivors, with the sperm they have taken in the suitcase, will found a new nest, first a small one, the size of a tennis ball, and there they will light up their first court of workers. , to later build a second nest, with the advantage that in summer the leafy trees serve as camouflage. It is a perfect storm.

The fact is that in the deactivated nest in the park there were only worker wasps left, without a queen or any equivalent leader. In its own way, that was a libertarian utopia and it is already known how all human attempts to create such radically horizontal societies have ended, with an expiration date on the cover. The wasps in the nest were doomed. The problem, at this point in the life cycle of the wasps, is not that nest, but the ones to come.

This is signed in full by the professor at the Autonomous University of Barcelona (UAB) Gerardo Caja, co-pilot of a project with a truly unbeatable name, UABee, which monitors the daily life of various panels installed on campus. First confirm that, indeed, 2021 has been a year of a surprising ‘baby boom’ and, from the point of view of the bees, fearsome. The ‘Vespa velutina’ is, as an adult, basically vegan, but it is a fierce hunter of insects, since they are the sustenance of the larvae. Their favorite prey seem to be honey bees. They are captured on the fly and quartered. They are only interested in your thorax. The UAbee project lets you make some disturbing rules of thumb. On average, each wasp kills about 25 bees a day. Each queen that survives the winter is capable, in a few months, of creating a nest with almost 2,000 individuals, of which several dozen will be future new queens. If the next question is how many potential queens are there in an environment, for example, like the UAB campus, the answer is distressing. “This year we have located five nests in the university, but only in the baits that we have installed in the area we have caught about 800 queens & rdquor;.

In the short term, that is, facing next spring, insects in general and bees in particular are going to be very disappointed. The ‘Vespa velutina’ has a few predators on this side of Eurasia. Magpies, blue tit and honey buzzard eats it with pleasure. The problem is that in the West, unlike what happens in the East, bees and these wasps have not coevolved. The natural balance is out of balance. Asian bees have perfected sophisticated combat techniques to defend themselves against aggression. The most striking is to form a cloud of flaps around the wasp. Thus they manage to raise the temperature a degree above what a wasp is capable of withstanding, 47 degrees, which ends up dying.

Related news

Some studies suggest that European bees that have reached Asia, such as the ‘Apis mellifera’, an invasive species there, have learned, so far clumsily, to respond the same in case of aggression. But those same bees, here, where it is their home, still behave with a blessed meekness. Wasps seem to have a predilection for bees that return to the nest after going from flower to flower, it is not clear whether because they are loaded with nectar and their flight is slower or directly because they like them coated in pollen.

If they have reached this last paragraph without showing symptoms of entomophobia, that is, fear of insects, they will be summoned for the next episode, probably in spring, when Roddy Romero and Jesús Jarque draw the rifle again or, if it seems little , by the time what has already happened in the United States happens, the arrival of the ‘Vespa mandarinia’, to which the wasp name comes small, so it is known as the Asian hornet. A few specimens are capable of decapitating the entire population of a honeycomb in a few hours and, to reassure the population, entomologists are supposed to say that human bites are rarely fatal. What a relief. Rarely.

Leave a Comment