Life Cycle of Oak Processionary Moth
Eggs are laid from July to early September. Each female lays between 100 and 200 eggs on twigs and small branches in the canopy.
Oak processionary caterpillars can be found from April to June. There are six stages during the caterpillar feeding cycle with caterpillars getting progressively bigger during each stage.
Stages 1-3: Caterpillars are very small when they hatch, around 2mm long, and are still less than 1cm by the time they reach the third stage.
Stages 4-6: Caterpillars spin silken nests and the larvae eventually moult to the pupal stage within those nests. During this phase, larvae may also be seen massing on the trunks and branches of trees and moving in the characteristic processions that give the moth its common name.
Adult moths have a wingspan of around 30-32mm and grey forewings suffused with white and some darker grey markings. This coloration provides an effective camouflage against the bark of oak trees on which the adults often rest.