The Asian wasp invades the Peninsula and jumps to the Canary Islands

On June 5, the Intervention team of the Canarian Early Warning Network for Invasive Exotic Species (RedEXOS) removed an Asian wasp (Vespa velutina) nest located on the façade of the IES Isabel de España, in Las Palmas de Gran Canaria. This is the first nest of this invasive species that appears in the archipelago after several years since its arrival in Spain, in 2010. «We had been paying attention for several years because on the islands there is a lot of maritime movement with the Peninsula and with the country of origin of the species, and we considered that at some point this could happen. The first nest was observed on the façade of a downtown institute, near the port area.says Sonia Marín, director and technical coordinator of the network. As a precaution, the authorities ask residents to report the presence of new nests or the detection of specimens, while the Gran Canaria Beekeepers Association (ApiGranca) calls for the implementation of a network of sentinel apiaries, following models already developed in other island territories.

The objective is to eradicate a species that is causing havoc among honey bees from Luna territory. In Catalonia, the agricultural union Unió de Pagesos, the Barcelona Beekeepers Association, Girona Beekeepers, Associated Leridanos Beekeepers and the Catalan Beekeepers Association warned a few days ago of a strong growth in the population of this species this year. Besides, They foresee losses of up to 65% in autumn honey production, peak activity season of the Vespa velutina. «The Asian wasp not only preys; The most serious problem is that It is placed in front of the hives and the worker bees stop going out to collect for fear.. This stress causes the queens to go from laying two thousand eggs a day to practically stopping doing so. The hive enters into population decline. Our way of preserving them is to feed them artificially during the winter with water, sugar and supplements to prevent them from dying,” explains Josep Maria Plaria, head of Beekeeping at Unió de Pagesos.

Another alarm signal has been made public from Galicia these weeks. The company specialized in pest control Serpa recently warned that “the intense winter rains have caused an extraordinary flowering, creating an ideal environment for the reproduction of this wasp.” Their technicians assured COPE a few days ago that they had recorded a number of queen captures that tripled that of any previous year since the arrival of the invasive species.

A voracious animal

The dreaded “vespa velutina” can reach three centimeters in length and feeds on bees and other pollinators. It arrived in Europe in 2004 through a shipment of ceramics from China that landed in Bordeaux. In 2010 it was detected in the Basque Country and, since then, It has spread throughout Galicia, Asturias, Cantabria, Catalonia, Navarra and La Rioja, in addition to being found less intensely in Castilla y León, Aragón and the Valencian Community. «On the Atlantic façade of the Peninsula he found a humid and mild climate similar to that of his place of origin. In the Mediterranean it is more difficult for it to prosper and, in dry years, populations decrease,” explains Joan Pino, director of the Center for Ecological Research and Forestry Applications (CREAF). The center warns that invasive exotic species like this one are increasing around the world due to a combination of factors such as globalization or constant movement of people and goods, urbanization, and climate change. Warm spring temperatures, in the case of the Asian wasp, advance and prolong the reproductive season.

Beekeepers apply their own treatments and demand greater coordination between administrations to implement effective control measures and reinforce surveillance. «The current situation is a direct consequence of the lack of actions during the periods considered critical to reduce the population of the Asian wasp. Since 2010 there has been monitoring and counting, but little else. From the first year we were told that the wasp was unstoppable and that nothing needed to be done to stop it. Nothing has been done,” says Josep Maria Plaria.

For a couple of years, many beekeepers have placed traps to capture founding queens using mixtures of sugar, yeast and alcohol. «When the nest is already established and the queen stops moving, the idea is to use the Asian wasp itself as a vector to introduce insecticides into the nest. We feed them with products such as Beauveria bassiana, a fungus that does not harm honey bees. If the wasp transports the fungus to the nest, the larvae end up dying,” he adds.

Is local control the only option against the Asian wasp? Is it impossible to eradicate it? Have you acted late? Joan Pino provides several keys: «Some methods are being imposed, such as the so-called Trojans, which consist of inoculating captured workers with toxic substances so that they transport them to the nest. There are also physical methods, such as electric harps, which prevent the passage of velutinas through controlled discharges, or Koldo traps, that capture Asian wasps but allow the bees to escape.

The researcher considers that the species “is here to stay”, although he is confident that its populations will progressively decrease as it is incorporated into local food networks and pressure from native predators, such as the bee-eater, increases. Regarding the possibility of having acted too late, he adds: «The ability to eradicate and control an exotic species depends on the reaction time. In the early phases there is a great eradication capacity, but as populations consolidate, options disappear and only local control measures remain. It has been slow to react, as usually happens, because the administration is slow in these cases. However, it must also be recognized that it is difficult to act against an insect with such high mobility. The only real options would have been to eliminate the first nests in Bordeaux. “We need much more powerful warning networks that quickly identify species with high invasive potential.”