They appear in masses. They wander around hectically. They nest wherever they can find living space. No, we are not talking about tourists who are coming to Barcelona in large numbers again at the beginning of spring. These invaders are called Paratrechina longicornis, commonly also: “crazy ants”. Not originally native to the Iberian Peninsula, the first specimens were discovered three years ago in the harbor area of the Catalan capital. The authorities responded with a radical extermination program. In 2022 it was said that the crazy crawlers would be extinct.
But as is the case with an insect that is one of the most resilient that nature has to offer, humans do not prevail that easily. Now are is Paratrechina longicornis back again: on the hill of Montjuïc and on the Plaça de Catalunya at the northern end of the Ramblas, of which they occupy at least half a hectare, as recently became known. The animals are already native to the Canary Islands and have also been spotted in some places on the Spanish southern coast.
Plaça de Catalunya at sunset.
(Photo: Alexander Spatari/Getty Images)
At least in Barcelona he had given up losing the war against this species, wrote local pest controller Carlos Pradera in a web article. But to write about “panic”, as some Spanish newspapers did this week, is inappropriate. The “crazy ant” makes an impressive appearance with its hyperactive movement, especially when hundreds or thousands of animals are scurrying around in one place. But they do not bite and do not pose a health risk, as the experts assure. When fighting other small animals, they can fire a shot of acid from their rear at the opponents. It is not entirely clear where the species comes from, some say Asia, others Senegal. In any case, she can set up her nest in any kind of man-made structure, writes Pradera. It eats almost everything, from small animals to carrion to honeydew, seeds and fruit.
This is one of the reasons why this type of ant can be a nuisance in homes. There are also fears that it will displace native species. On the other hand, invasive species are part of the reality of life in the globalized world: In the Balearic Islands, for example, the most common of the 60 ant species known there is an invasive species, the Argentine ant. “She came to the popular holiday islands in the 1950s,” said Miguel Ángel Miranda, dean of the zoology faculty at the Balearic University, the German-speaking one Mallorca newspaper. It forms super colonies with millions of individuals and has several queens.
The two to three millimeter long “crazy ant” differs from other species not only because of its hectic movements, but also because of its particularly long antennae and long hind legs. And the fact that she feels comfortable on the Plaça de Catalunya has something to do with tourists: it is an ideal place for this species, writes pest controller Pradera. There is less natural food there, but there is leftover food. They are the remnants of another invasive species: bipeds from all over the world that move through Barcelona as erratically as crazy ants.