line of pine processionary caterpillars on wall. close up of larvae of thaumetopoea pityocampa

pine processionary allergies allergic insect larva moth larvae caterpillar urticating hairs thaumetopoea pityocampa behaviour thaumetopoein irritant irritative invasive species global warming caterpillars hairy line forming procession close detail closeup destructive column nosetotail columns processions wall