All caterpillars produce silk from silk glands. The silk is used for a variety of purposes including communication, defense and as a structural material. Caterpillars may enclose themselves in leaves, often for protection against parasitoids, predators or inclement weather. Some caterpillars will feed inside leave rolls or ties. Other caterpillars will tie leaves to make a protected site for pupation.
The caterpillar below has parked on the surface of a plastic container in preparation for pupation. The caterpillar has used silk to wrap itself with a leaf (which is slightly pulled away for better viewing). How does the caterpillar manage to “pull” the leaf around itself? The silk is a sticky protein that the caterpillar forces out its silk gland. The caterpillar will attach the strand to one surface to be tied, then stretches the silk strand before attaching it to the second surface. After the silk is attached, it will contract to pull the surfaces together. Caterpillar silk can generate a force 30 times the force of gravity to hold surfaces together.
Caterpillar uses silk to tie a leaf to a surface and create a shelter for pupation.
Caterpillars do some amazing things with their silk. I’ve always been impressed that the little baby Spicebush Swallowtail caterpillars manage to roll thick leaves over themselves. Right now we have a Red Admiral caterpillar inside that we have been watching. They like to make little leaf houses by attaching leaves together. What kind of caterpillar is that in your picture?
The caterpillar in the picture is a gypsy moth, Lymantria dispar.
We had huge flocks of red admirals in Indiana this year.
What kind of tree is your red admiral on?
Ours is on false nettle (Boehmeria cylindrica). It frequently attracts red admiral eggs around here but the caterpillars get taken by predators pretty early on. This one we brought in as a very little guy as soon as we saw him. False nettle holds up very well in water so it is easy to bring cuttings in – they actually root while the caterpillar is munching away up above.