Processionary caterpillars in Spain: Their life cycle and hidden dangers

by Lorraine Williamson
processionary caterpillars

Spain, with its diverse ecosystems and rich biodiversity, is home to a variety of fascinating creatures. Among them, processionary caterpillars stand out due to their unique behaviour and potential dangers.

In this article, we will look at the life cycle of processionary caterpillars, exploring their habits, habitats, and the risks they pose to both flora and fauna.

The life cycle of processionary caterpillars

Egg Stage

The journey of processionary caterpillars begins when adult female moths lay their eggs in the branches of host trees, such as pine, cedar, and oak. The eggs are laid in clusters, resembling small, frothy masses.

Larval Stage

Once the eggs hatch, the larvae emerge and form silken nests (that look like candyfloss) around them. These nests serve as protective shelters during the larval stage, where the caterpillars feed on the leaves of the host tree.

Pupal Stage

After completing their feeding phase, the caterpillars enter the pupal stage. They leave their nests and burrow into the soil to undergo metamorphosis. This stage can last several weeks or even months, depending on environmental conditions.

Adult Stage

The adult moths emerge from the pupae and the cycle repeats as they lay eggs, continuing the fascinating life cycle of processionary caterpillars.

Behavioural traits

One of the most captivating aspects of processionary caterpillars is their distinctive behaviour during the larval stage. They are known for moving in long, single-file processions, hence their name. The caterpillars follow a leader, forming a line that resembles a procession – a behaviour believed to enhance their chances of finding food and shelter.

Dangers posed by processionary caterpillars

While the processionary caterpillars play a crucial role in the ecosystem by serving as a food source for birds and other predators, they also pose significant dangers to humans, animals, and the environment.

Health Risks

The caterpillars are covered in tiny, barbed hairs that contain a protein called thaumetopein. Contact with these hairs can cause skin irritation, rashes, and, in severe cases, allergic reactions.

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Defoliation of trees

The feeding habits of processionary caterpillars can lead to the defoliation of trees, causing harm to the affected vegetation. This can be particularly concerning in forested areas, impacting the overall health of ecosystems.

Dangers to pets

Dogs and other curious animals are at risk of coming into contact with processionary caterpillars. Ingesting or even sniffing these caterpillars can result in serious health issues, or even death for pets.

What can you do if you have these trees in your garden?

Tree treatment

To safeguard your surroundings from the potential hazards of processionary caterpillars, considering professional tree treatment is a proactive measure. Arborists and pest control experts can apply targeted solutions to the host trees, preventing these voracious insects from causing extensive defoliation. Treatment methods may include specialised pesticides or biological controls that disrupt the life cycle of the caterpillars.

Avoiding contact

Prevention is key when it comes to processionary caterpillars. It’s crucial to avoid any direct contact with the caterpillars or their nests. The tiny, barbed hairs covering their bodies can cause skin irritation and allergic reactions. Protective clothing and gloves should be worn when handling potentially infested trees or attempting any removal.

Pet safety

Pets, especially dogs, are naturally curious and may come into contact with processionary caterpillars during walks or play. If your pet has encountered these caterpillars, it’s essential to act promptly. Signs of distress may include excessive drooling, pawing at the mouth, or difficulty breathing. In severe cases, ingestion can lead to serious complications, including death or the need for extreme measures such as tongue amputation.

What to do if your pet is exposed

  1. Do Not Delay: Seek veterinary attention immediately if you suspect your pet has come into contact with processionary caterpillars.
  2. Do Not Touch with Bare Hands: Wear gloves when handling your pet to avoid contact with any caterpillar hairs that may be on their fur.
  3. Rinse Mouth and Eyes: If safe to do so, rinse your pet’s mouth and eyes with water to remove any caterpillar hairs. Be cautious not to get any hairs on your skin.
  4. Visit the Vet: Promptly transport your pet to the veterinarian for professional assessment and treatment.

Dangers of DIY removal

Attempting to remove processionary caterpillar nests without proper precautions can lead to severe consequences. The hairs, once airborne, can pose a risk to your health, causing respiratory issues and skin irritation. Moreover, DIY removal may disturb the caterpillars, causing them to release more hairs into the environment.

Professional intervention is recommended
  1. Hire Experts: Engage the services of pest control professionals or arborists experienced in dealing with processionary caterpillars.
  2. Protective Measures: Professionals will take necessary precautions, such as wearing protective gear, to minimise the risk of exposure to the irritating caterpillar hairs.
  3. Safe Disposal: Allow experts to safely remove and dispose of the caterpillar nests, reducing the likelihood of unintentional exposure.

Also read: The dangers of processionary caterpillars

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