Follow the leader

Processionary caterpillars (Ochrogaster lunifer) are the larvae of Bag-shelter Moths. At this time of the year they can be found feeding mainly on acacias and grevilleas. As the name suggests the caterpillars shelter in a bag made of silk usually situated in or the base of a food tree.

When a given tree has been defoliated the caterpillars move to find another food source. The lead caterpillar leaves a physical trail in the form of a silken thread as well as a pheromone trail which successive caterpillars will follow head to tail in lines up to several hundred individuals. The picture below shows a procession of only a handful of individuals – I guess trying to walk up the bike path is asking for the silken thread to be periodically wiped out by passing cyclists. A processionary line is also formed when the caterpillars look for a suitable location to pupate (underground).

Both the caterpillars and the adults are covered in fine hairs. These are quite poisonous as they contain an anti-coagulant that can cause hives if touched. The fine hairs from the caterpillars are also suspected to cause premature abortion of the foals in horses.

Not everything fluffy is cute and cuddly!