A plague of caterpillars of the thistle butterfly (Vanessa cardui) has surprised the residents of different municipalities on the island of Tenerifefundamentally, to those of Güímar and Arafo. Residents of these areas of the island say that “these worms are everywhere, invading sidewalks, roads and terraces». The biologist and president of the Neotropic Foundation, Jaime de Urioste, explains that there has been a “demographic explosion” of this butterfly due to the environmental conditions that are occurring in the Archipelago, and specifically, in Tenerife.
In this sense, points out that the tropical storm that affected the Canary Islands at the end of September, ermine, that brought abundant rains, and “the heat and humidity that we have had afterwards”, have generated the ideal conditions for the reproduction of this and other species, like flies and the millipedes, whose high number has also surprised the neighbors.
“We are talking about an abnormal situation, because with the rains the temperature usually drops, which has not happened this time. Therefore, in this case, all the ideal conditions for these butterflies are present, humidity, heat and the presence of some of the nutritious plants on which they feed, such as thistles or dead tooth” , comments De Urioste.
He adds that he has increased the reproduction of these butterflies, whose population is usually controlled, as well as the plants they feed on. “Suddenly, these butterflies lay a lot of eggs and the caterpillars, being so many, move desperately everywhere in search of food or to be able to enter the chrysalis stage.” Of course, the president of the Neotropic Foundation, and head of the only exotic fauna center that exists in the Canary Islands, wants to send a message of calm to the population, “because this species is not invasive and does not cause any type of damage.” And besides, he jokes, “they are prettier (referring to butterflies) and less annoying than flies.” He points out that “this is a temporary situation”, so when the cold arrives, the plague will disappear.
Initially, this plague has been detected mainly in the municipalities of Güímar and Arafo, although it is not ruled out that other areas of the island will be affected, according to Jaime de Urioste. The millipede worm plague has appeared in different urban centers of La Gomera, Tenerife (for example, in the municipality of Adeje) and Gran Canaria. And the presence of the fly has multiplied practically throughout the Archipelago.
The biologist Jaime de Urioste points out that some of the thistle butterflies are “native to the Canary Islands”, but, he adds, the majority are “migrants”. “Coming from Africa, some go to southern Europe and others reach the Canary Islands.” Vanessa cardui is one of the butterflies with the widest geographical distribution, being found on all continents except Antarctica. It can live in any temperate zone, including mountains in the tropics.
