The crazy ant (Paratrechina longicornis) is spreading through Barcelona and it is not ruled out that it is also present in other parts of Catalonia. The first specimens of this invasive species were discovered on the grounds of the Port of Barcelona in 2019. The rapid selective insecticide treatment managed to control the expansion in this area, considering it eradicated in 2022, but now new outbreaks have been observed in Montjuic (in the cemetery and in the gardens of Mossèn Costa i Llobera) and, even more striking, in the heart of the city, in Plaza Catalunya, as confirmed by Roger Vila and Carlos Pradera, experts in the study of insects and pest control.
In the case of the port, these ants were detected when it seemed that they had only recently arrived, perhaps accidentally introduced into some cargo, which facilitated treatment until they were considered eradicated, but in the new cases, experts consider that the extension can be “unstoppable”, Carlos Pradera and Roger Vila agree. “We are facing an example that, in cases of species invasion, rapid detection and action can be effective, while the lack of control and delays in response make it impossible to avoid expansion, with the environmental consequences that this can have” Roger Vila, head of Bionet, explains to La Vanguardia. Vila points out that in the case of Paratrechina longicornis there is no risk to human health.
The outbreaks detected in the cemetery and the Costa i Llobera gardens are located 1.5 and 0.6 km, respectively, from the port area where the first specimens were located. “This area is very large and seems intractable if there is no will for it, that is, budget. Therefore, I consider the war against this species in Barcelona almost lost and in coming years it will be a trickle of new records throughout the metropolitan area,” explains Carlos Pradera in a note on his website “The disinfestator and deratizer, pest control in the Barcelona area.
The first location of the crazy ant in Plaza Catalunya was made by biologist Erik Rodríguez, who was able to capture a specimen and take photographs with a binocular magnifying glass. Shortly after, Carlos Pradera was able to personally verify the presence of the crazy ant in this central area and preliminarily determine some characteristics of the colony. “The ant seems to occupy approximately half a hectare in Plaza Catalunya and could be present in this area for three years or more because the arrival of a queen with a few workers is not enough to create a new population, at first the occupation is slowly, although it is accelerating with the growth of anthills with many queens in each of them,” explains Carlos Pradera.
Plaza Catalunya “is an ideal place for this species, it may not have many arthropods to capture, but it has a lot of food remains everywhere, since it is full of people, especially tourists, at all hours.” “In addition, there are trees where they can find food; we know that they look for the secretions of aphids and aphids,” explains this expert on ants and other pests in the Barcelona area.
Carlos Pradera points out his experience in treating a crazy ant infestation last fall in a hotel in Mallorca that was “taken over” by nests of this species. “P. longicornis had an impact not only on the exterior [of this hotel], but also on the interior. The workers go for any food they find and can move many meters in search of food. This species is structural and can locate its nest in any human construction,” explains Pradera.
The Miteco file on this species summarizes its characteristics, recalling that the crazy ant is an “opportunistic omnivorous, predatory and scavenger species that consumes live or dead insects, molasses, seeds, fruits, etc.” “It is a very adaptable species, which lives in both dry and humid environments. Polygynous species, with each colony having numerous queens. The colonies are temporary, moving them very easily when they are disturbed, and are often found at a certain distance from their home area. feeding”.
Regarding the main effects, the official file indicates three sections: “Ecological impact: it can displace other native ant species, as well as other invertebrates.” “Economic impact: it can be considered an agricultural pest, as it helps in the distribution or protects hemipteran sucking insects, mealybugs, aphids, etc.” “Social impact: It can be a plague in homes.”
