Processionary caterpillars are out and about

Hundreds of these caterpillars travel head to toe looking for food or a place to pupate (turn into their adult form: the bag-shelter moth)
Hundreds of these caterpillars travel head to toe looking for food or a place to pupate (turn into their adult form: the bag-shelter moth)

In late summer and early autumn the processionary caterpillar has been known to horrify the odd gardener on the Mid North Coast.

They travel in long lines of hundreds or more in search of food or a suitable place to begin the transformation into their adult form: the bag-shelter moth (Ochrogaster lunifer).

Together they present a formidable number of irritant hairs to predators and the conga line helps prevent them getting lost.

It’s not just predators who need to look out for those stinging spines, but curious dogs with their sensitive noses.  

Needless to say, humans are best advised to avoid contact as the hairs can easily penetrate skin and break off, and are difficult to remove thanks to hundreds of microscopic barbs. The hairs contain an irritating protein that can produce an allergic response and even eye injuries.

Ian Bryant from the Coffs Harbour Butterfly House has been sent a few photos of the caterpillars recently with people wanting to know more about them.

He agrees that gardeners are best to look out for them at this time of year and avoid contact.

“Like all hairy, spiny caterpillars, they are best avoided.”

When they’re not out and about in procession, they rest together in a silken bag.  In coastal areas, the bag is located on the ground at the base of the trunk of the food tree; while in inland areas the bag is located up in the canopy.

The caterpillars mostly feed on wattles and sometimes can strip a whole tree.

The caterpillars are fully grown in May and ready to leave their wattle trees – once again in procession - but then breaking up into groups of ten or less.  Each caterpillar forms a chamber of soil and silk incorporating their long hairs.

They then sit out the winter within their cocoons and the adult moth does not emerge until late October.

When they become moths they are generally brownish in colour with a wingspan of around 5cm.  Both sexes have an orange abdomen that is banded with brown.