The female moths don't fly, she just sits on the trunk of the tree while the males flies around servicing her.That is some sight……. we had them like that years ago but Im not sure that they stay in the ground and rise over time in cycles or what causes them to appear..
Lays a egg sack that is a creamy colour, which contains around 300-1000 eggs.
They then hatch the following year, crawl up, eat, drop, crawl up, eat, going through the full until full grown and pupae stage.