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Poisonous caterpillars, which can give a nasty sting,
can be found along the coast and anywhere there are pine trees. They are particularly active during March and April.
The Spanish call them 'Procesionaria del pino' (procession of the pines), and they are called
'Processionary caterpillars' in English. They are easy to identify owing to their peculiar
habit of travelling along in groups, one behind the other, forming a long single file
'procession' - hence their name. Long hairs which cover the caterpillars give out poison when touched, producing a sting like nettles which irritates the skin and mucous membranes. Although in most cases the poison has no serious consequences, allergic reactions are not unknown, and if the caterpillars are ingested then the consequences can be extremely serious. |
The risk to humans of serious complications resulting from contact with the caterpillars is minimal in healthy people.
The real victims of these caterpillars is actually the pine trees on which they live as they form an annual plague which is fairly common in Spanish pine and cedar forests. They cause damage to the trees by consuming enormous quantities of foilage and although they rarely kill the tree it can leave the tree unable to defend itself from other enemies.
Like all caterpillars the processionary goes through a cycle which includes metamorphosis. The moth lays between 120 and 300 eggs in a group of pine trees and the caterpillars hatch out between 30 and 40 days later and immediately start feeding before moving on.
They construct large silky cocoons where they form a colony and begin to undergo five phases of change. These cocoons are easy to identify as they look like large messy spiders webs in the branches of the trees.
It is in the third stage that they develop their toxic hairs and during the fifth phase which lasts about 30 days (typically around March/April) is when people and animals are most likely to come into contact with them. In this fifth stage a colony can completely strip a pine tree of its needles.
The colony then forms a procession to search for other pine trees. Then, when the temperature reaches about 20 degrees centigrade, the processionaries travel to the ground to bury themselves where they then change into moths.