Procession Caterpillars – Friend Or Foe?
Caterpillars remind me of my garden, eating the plantation, small, harmless, maybe even cute but annoying to the plant life with no risk to me, children or my pets. Ask me about procession caterpillars and I will give you a completely different answer. Friend or foe?
Foe would not even begin to describe these characters, they are the enemy and should be avoided at all costs. Enemy probably sounds too strong a description for a little hairy caterpillar but trust me, do not make a judgment because of its size or because you have always liked them.
Procession Caterpillars are found across Europe, especially in Mediterranean countries where the temperatures are generally warmer, specifically titled Thaumatopoea Pitycampa or the caterpillar of the pine tree. They are considered a threat to the trees, dangerous to animals and to people can cause a very strong allergic reaction caused by the hairs found on their backs.
Traditionally, the nests are found in the pine trees and their home is usually positioned on the sunny side of the tree and can often be spotted from a distance where the pine needles have turned brown.
On closer inspection, white candy floss woven on the branches and delicate silk bags can be seen decorating the trees. These are the nests of the procession caterpillars, protecting them as they grow and keeping them warm.
To feed, they leave the safety of their home at night and walk along the branches to demolish and quake on the pine tree, venturing further afield once they depleted the supplies. They are greedy and destructive and are active in the winter months, often feeding in zero temperatures before returning to the nest to rest and digest their feed in the warmer, sunlight hours.
In March when they are fully grown they commemorate the next stage of their journey, leaving the safety of the nest and tree in search of a burial site.
Why are they named procession caterpillars? When they start to move, they look as though they are marching, like an army in a line, head to tail determined to find a suitable pupation site in the soil. They may travel long distances from the host tree before they bury themselves, spending the warmer months buried as a pupa. In August, the moth emerges from its cocoon, mates and lays its eggs in a pine tree and the cycle commences all over again.
We have lived in Spain for several years now and we have a lovely pet dog named Angel, who is a West Highland Terrier, who loves to prey to hunt and explore the woods around the pine trees. We have never experienced any problems and for the majority of the year it is a safe and pleasant place to walk. During the first quarter of the year, January through April we do have to be vigilant and we prefer to find other areas to walk.
The beginning of the year is the most dangerous time for exposure to the caterpillars, although the nests are formed before then. Due to the weather being warmer, whether climate change is to blame or not I do not know, but I have seen the caterpillars in the woods feeding and away from their nests in early December, although unusual.
True to her breed, Angel is always sniffing in bushes and tracking a smell through the undergrowth and it is this behavior that causes her the greatest threat. Along the back of the insects are fine, irritating hairs that if inhaled, licked or indeed ate the caterpillar can cause her great pain. Dogs, cats and foxes are among the animals at most risk to these insects, attracted to them because of their color and some say their odour.
If the hairs come into contact with the animals lips or tongue, the area will swell very quickly and cause a large amount of pain and we need to ensure this does not asphyxiate them. If the caterpillar has been eaten then the symptoms are more severe with vomiting, a fever and blood present in the urine. If you suspect your animal has come into contact with the caterpillars you must take them to the vet immediately, the faster the treatment can be administrated the better.
The hairs on the procession caterpillars are released into the air and do not have to be attached to injury injury. Beware, poking the insect with a stick or treading on them will only release the hairs into the environment and you will become more susceptible to inhalation. Even if the caterpillar is dead the hairs remain dangerous.
Disposing of the nests during the winter months should be left to the professionals, although spraying the nests with hairspray to ensure the hairs do not disperse into the air, covering with a plastic bag and cutting the branch down is the usual treatment before setting the nest On fire. Protective clothing including goggles must be worn, so leave it to the experts. A procession of caterpillars are usually set alight after dousing them with lighter fluid, again to prevent the hairs from circulating.
Please note, I do not advocate this procedure as the trees and woodland are often dry and desiccated and this poses a real threat to forest and bush fires.
Please keep your pets safe, do not panic about the procession caterpillars, learning to live with them, being careful and aware helps to prevent any problems or encounterers with the insects. They are not around all year, it is only for a short period of time that you need to be vigilant. Remember, if you think your pets have come into contact with them or indeed yourself seek veterinary and medical assistance immediately. Photographs of the caterpillars can be found on my website.