Who hasn’t looked at a bird’s nest and admired the skills of its avian architect? Now I ask you to turn your attention to what lowly insects can do. A variety of insects and spiders use leaves to manufacture a shelter for their young. This nest, more properly called a nidus, is the work of a Leaf-rolling Weevil:
She is 1/8″-1/4″ long, and her Latin name is longer than she is: Synolabus bipustulatus (or should I say Synolaba bipustulata?):
She lays a single egg then rolls the leaf up around it. When her larva hatches, it eats the leaf material from the inside.
Every year, the hydrangea outside my door hosts a colony of shelters made by the Hydrangea Leaf-tier Moth, Olethreutes ferriferiana, a species of tortricid moth. This one is made of two leaves. The caterpillar lays down a line of silk cement on the inside of the outer leaf edge, and then somehow brings the edges together, enclosing a bud, which provides it with food..
If you cut one open and look carefully, you find the caterpillar,
or, in an older one, a pupa. (You can see the marks where the caterpillar ate the inside of the leaf.)
My hydrangea thrives every year, so I don’t worry about the leaf packages, I just admire the handiwork.
Sometimes in the woods I find elegantly folded leaf nests, like this fortune cookie shape:
or this one with a strip of leaf like an obi wrapped around it.
You can see the silk strands that sew it together.
These might also have been made by caterpillars, or perhaps by nursery web spiders to hide their egg sacs. I didn’t have the heart to destroy one to find out.
PS If you find this sort of thing fascinating, as I do, I highly recommend Tracks and signs of insects and other invertebrates: A Guide to North American Species, by Charley Eiseman and Noah Charney.