This is the cocoon of the Urodid Moth, and it is entirely unlike other cocoons you're probably used to seeing. The pupa is housed within what looks like something that came off a 3D Printer. Just another example of how we're lagging behind the art already found in nature!
But why does this species prefer a cocoon that seems so, well, vulnerable? Destin from Smarter Every Day talked to a butterfly farmer to find out why the strategy of building a net, rather than a shell, works for this type of moth.
From the video, "This type of cocoon is known as a 'open-network cocoon' and is unlike other cocoons in that it doesn't completely enclose the pupa in silk. Instead, it only partially surrounds it, likely enabling better airflow to control for humidity and may help prevent fungi from growing on, and eventually killing, the pupa. This cocoon very likely belongs to a moth in the family Urodidae, which is known for making this type of lattice-structured cocoon surrounding its pupa."
So the cocoon's open structure, and that it hangs in mid-air, keeps the pupa from drowning in a rain shower, or being destroyed by ants or fungus. Though it looks fragile, this cocoon is actually a brilliant survival strategy. Mind-blowing.