Ecologia comportamentale e socialità in processionarie australiane ed europee

Pest insects are an ongoing issue to human society. Containment of pests can become problematic, especially when the species are gregarious and are a health risk to humans and animals. A species of recent interest is the processionary caterpillar, Ochrogaster lunifer, a urticating species found in Australia and associated with defoliation of acacias and eucalypts. A similar European species is the pine processionary moth, Thaumetopoea pityocampa. The caterpillars are destructive defoliators of pine and cedar trees in the Mediterranean Basin and Southern Europe. Both O. lunifer and T. pityocampa caterpillars live gregariously in a communal nest from egg to final instar larva. Setae (detachable urticating hairs) from the abdominal segments of O. lunifer and T. pityocampa caterpillars are responsible for various health issues to humans and animals and therefore require management actions. Comparing the two species of processionary caterpillars from opposite hemispheres will enable unique management strategies suitable for two different climates and environmental conditions. In this thesis, I have identified and filled several gaps in our current knowledge about social caterpillars. To fully understand the movement ecology and social behaviour of T. pityocampa and O. lunifer, it required a multiple factor approach. The thesis outlined several hypotheses which were explained by quantitative and manipulative behavioural, physiological, and ecological studies. Such information is important in building a model to predict possible future outcomes and aid in pest management. We have suggested targeted pest management strategies of the two processionary caterpillars using: pesticide and/or nematode application in predicted pupation sites, manipulation of pre-pupation processions through the obstruction/interference of polarisation vision in caterpillars, precise application of entomopathogenic bacterium on vulnerable younger larval instar colonies using drones (unmanned aerial vehicles) or manual sprays, and releasing natural enemies or spraying pesticide at exactly when caterpillars are outside maintaining the tent. Filling the gaps of the well-studied T. pityocampa and understudied O. lunifer and doing a comparison of the two species bring out new concepts and patterns about sociality in Lepidopteran caterpillars.