nest oak processionary caterpillar in an oak tree. poisonous hairs are dangerous for human

net nest aterpillars group caterpillars toxic poisonous tree moth oak animal nature larva hairy insect natural dangerous health hazard thaumetopoea allergy macro caterpillar forest larvae pest problem butterfly europe spring processionary damage pine wildlife beware invertebrate lepidoptera allergic warning caution poison banner swarm fun moths leaf reaction processionea hairs are for human thaumetop tree