This is the first time the species has been detected in the Portuguese capital. A nest in one of the trees was found and eliminated on Thursday night in the gardens of Quinta das Conchas e Lilases, in Lumiar, Lisbon. The space remains closed until the insects are certain to have been completely eliminated.
The gardens in the Lumiar parish of Lisbon were closed down after a nest of Asian wasps was found in a tree. According to a post published on the municipality's Facebook and Twitter pages, the nest was "eliminated overnight" on Thursday.
This is the first time the Asian wasp has been detected in the capital. It's a debut, but not a surprise: this invasive species, originally from Southeast Asia, is thought to have entered Portugal from the north in 2011, and has since migrated south. In April 2018, the Lisbon City Council created a prevention program.
The biologist Maria João Verdasca told the press that the possibility of the arrival of this insect to the region was, by then, "very real". A Lisbon Council official confirmed that this is an unprecedented situation, adding that the municipality will now proceed to check all the gardens and green spaces of the city, an action that is already carried out, but will now be targeted specifically for the Asian hornets.
The nest that was found in the gardens of Quinta das Conchas e Lisases was burned. A toxic product was also used to ensure all hornets were eliminated. This is a critical point in the elimination of this insect, as the hornets that survive the process can later found new nests.
The gardens will be "reopened as soon as the Lisbon City Council receives the final report confirming that all the conditions for its use are assured", writes the municipality on Twitter.
The Asian giant hornet is an invasive species, originating from northern India, eastern China and Indonesia. It reached Europe by sea in 2004, probably via the port of Bordeaux in France, and then expanded to other European countries.
This species is carnivorous and predatory of the European honey bee. It is in beekeeping that the Asian hornet causes the most damage by attacking indigenous bees and by decreasing honey production and plant pollination. Therefore, it can also affect the production of fruits.
In 2010 it was detected in Spain and in 2011 its presence was first confirmed in Portugal, in Viana do Castelo. "Everything indicates that it will have arrived by land, in a load of wood," said researcher Maria João Verdasca. Asian hornets are no more aggressive than their local counterparts, but they become especially dangerous when they feel their nest is threatened, attacking in groups with chases for several hundred meters. On the other hand, being an invasive species, it can cause serious imbalances in the biodiversity of ecosystems.
