Caterpillars from separate egg masses laid close together are likely to join to become one big nest (see photo below). This nest was formed from 3 egg masses. It is common to find egg masses/nests on previously infested host trees (you can tell by the caterpillar frass (poo) and shed exoskeleton surrounding/underneath the current nest).
We have also found a few cases of ground nesting caterpillar egg masses laid in the tree fork which is uncommon since they usually lay on the tree trunk (see photos below). This egg mass has successfully developed into a nest above ground!
Eggs have hatched and the processionary caterpillars are now at their second or third stage (instar). These stages feed during the day on their host tree so you may see them especially in the morning. Later stages feed at night.
Adult Bag-shelter moths (Ochrogaster lunifer) have been emerging from pupae during October and egg masses are starting to appear in areas where the moth is prevalent. There is 5 – 6 week window from egg lay to when the 2nd stage (instar) caterpillars start feeding in the tree canopy. Although only about half of the egg masses laid by female moths develop into caterpillar nests, this is a good time to remove any egg masses seen on properties that have the potential to cause problems later in the season. When removing egg masses observe all safety procautions including avoiding contact with skin and eyes, avoid breathing in the moth scales covering the eggs, do not remove in windy weather, and hypersensitive individuals should not attempt removal.
This talk will be on in the Ecosciences building at Boggo Road precint: Seminar Room, Ground Floor at 1pm. It is a meeting of the Entomological Society of Queensland and visitors are very welcome: www.esq.org.au/events
New images from the 2015/2016 caterpillar season are being added to this site from June 2016.