They’re back! It’s January and over the last couple of weeks many pine trees have acquired some intriguing cobwebby pouches at the end of their branches. If you were to see them you may well be tempted to
have a closer look or even worse have a gentle prod and poke. Don’t do it! What you have come across is the winter home of the Pine Processionary Caterpillar which can be dangerous to humans and inquisitive pets. Sounds crazy I know. But these caterpillars have stinging hairs that may cause nasty, painful, itchy rashes, inflammation, and in severe cases, anaphylactic shock.
The Pine Procesionary Caterpillar is prevalent throughout Southern Europe. It is the larva of quite an inconspicuous looking moth (Thaumetopoea pityocampa) which lays it’s eggs in Pine trees from July/August. The caterpillars hatch and live unobtrusively in the tree until they reach the 3rd moult. It is at this stage – usually around January -when they develop the stinging hairs and when they also build their large silky pouches, communal nests which may each contain up to 300 caterpillars. Each night the caterpillars emerge and eat the pine needles retreating back into their pouch during the day. A pine tree with a bad infestation can have many branches stripped bare.
The next stage of this caterpillars life is even more fascinating. When fully grown – usually around February or March – they leave the tree en masse travelling nose to tail in a single file procession!
They are going in search of soft ground where they will pupate before emerging as moths in July/August. These processions can be several metres in length and is another time when people and pets may be have a close encounter they may regret. From a young age the local children are generally well aware of the dangers of these caterpillars. Many curious expats, visitors and pets have found out about them the hard way. Seriously – veterinarians are often called on at this time of year to treat an inquisitive dog with a sore and swollen tongue from investigating these intriguing processions. I’ve also heard tell that even golfers have abandoned their games when these Pine Processionary Caterpillar are marching over their fairways!
It’s a fascinating life-cycle and behaviour for sure. But you’ve now been warned! If you see these caterpillars or their nests in your gardens or when out walking – beware! Don’t go poking and prodding or letting your pets near them!