Loose Nests of the processionary caterpillars in the affected trees can be clearly seen. Significant volume growth losses occur in adult forests. Disboliation damage and the presence of caterpillars are a cause of warnings in trees that have been in recreational and residential areas.
From the third phase, The caterpillars have stabbing hairs, which can cause allergies, even in household and farm animals. This effect not only occurs when caterpillars are present, but also the following summer due to the persistence of allergenharen in the remains of winter nests. The larva of the procession Van pines causes serious descaling, reducing the viability of oak.
The processionary is part of the ecosystem
The Oruga of the procession Del Pino is one of the most media rings in the spring, because the body is covered with stabbing hairs that influence people and pets. However, it is important Remember that the procession is a kind of native butterfly And that under normal circumstances is in balance with the ecosystem and offers a series of benefits. We tell you!
- The eggs. In the summer, when the moth places the eggs in the pine activities, they serve as food Ants, wasps and cicadas.
- Early caterpillars. When they improve their cycle and are born, from August (in colder areas) to October (on the coast), they become food for insective birds, such as the Normal Caronero, the regular Herrerillo or El Cuco.
- Advanced phases. Between February and March, when the caterpillars fall into procession and are buried, The Mirlo, the Abubilla and the Cuervo They find them and catch them.
- The moths They are also an attractive food for it bats and lirones.
The caterpillar and his parasites
Later, The humidity and funeral of caterpillars prefer the germination of the fungus On the Chrysalis, which little by little feeds out until the butterfly that develops dies.
In the same wayThere are some parasitoids (who eventually kill their guests), Mainly Hymenoptera, which the procession In his egg phase. The most deadly species are Tetrastichus Servadei Y Oencyrtus Pityocampaewho have a major impact on the populations of Processional, Even larger than that of birds and other predators.
Pine -benefit
This process of Leave the renovation is gradually done by pines because they are multi -year and They do not lose the leaves annually, but the procession It can help to promote this renewal with Destroying. Thus, the year in which it is influenced, the den less will grow and concentrate its energy on producing new leaves, without this affecting the growth in the long term.
Do the pines suffer?
The procession It has a complex life cycle and follows a metamorphosis process, through different stages, like all butterflies. First, the caterpillars come out of the eggs in the fall and start Enter en masse from the pine leaves. When winter arrives, with low temperatures that can be fatal for the Processional, The typical white sides bags appear at the top of the pines. Inside These bags, the caterpillars seek his refuge in a group To survive the cold and leave at night to feed.
In general, the pines recover easily. However, With climate change, the winters are softer And more caterpillars survive than normal. When we have spent warm winters, most caterpillars have survived in the bags, what a Increased population in the latest development phase And a greater impact on trees.
Moreover, the problem is exacerbated when we combine the predation of this species with drought and increased temperatures. These combined factors weaken the health of the pines to the point that if they become a strong attack Processional, lIn the absence of water, high temperatures and descaling can prevent their recovery.
Finally, we must bear in mind that if this situation is repeated in consecutive years, this can limit the power to restore the pines. In Catalonia we had three very difficult years until 2019, But since then, the population explosions of the procession have been moderated.