Living With Processionary Caterpillars

Bag Shelter Moth Processionary Caterpillars
Photo: Christopher Watson

Caterpillars of the Australian bag shelter moth, Ochrogaster lunifer, feed at night and spend the day in shelters of silk, debris and fecal matter.  The caterpillars feed on leaves from Acacia, Eucalyptus and Corymbia. If the caterpillars defoliate their host, they wander in search of more food. The caterpillars secrete silk and a pheromone to produce a trail. Caterpillars will follow the trail and will travel in a head to tail procession of caterpillars.

The caterpillars produce a prodigious number of urticating hairs estimated at 2.0 to 2.5 million setae in a fully developed caterpillar. The defensive hairs contain an anticoagulant that is toxic to vertebrate predators. Contact with the caterpillars can cause skin irritation. The hairs persist on the cast cuticles of the caterpillars and can be distributed over a wide area when nests are blown apart by wind. If consumed by pregnant mares, the urticating hairs can cause equine amnionitis and fetal loss. The hairs can work their way into the placenta, damage the fetus and result abortion of the fetus.

L. E. PERKINS, M. P. ZALUCKI, N. R. PERKINS, A. J. CAWDELL-SMITH, K. H. TODHUNTER, W. L. BRYDEN and B. W. CRIBB. The urticating setae of Ochrogaster lunifer, an Australian processionary caterpillar of veterinary importance. Medical and Veterinary Entomology (2016) 30, 241–245.
doi: 10.1111/mve.12156