Some species can spin silk from glands in their mouth.

The mature larvae spin silk and are fixed at the tip or base of the leaf where pupation takes place.

It will occasionally spin silk over the pupae.

Young larvae spin silk threads and are easily blown by wind to various parts of young leaves and buds.

Caterpillars spin silk prolifically and in comparison to other non-eusocial insects build large and relatively complex structures from the material.