I'm guessing that it evolved the fence to prevent crawling predators from feasting on the cocoon while the bug is pupating. That said, its a really interesting example.
The next time the guy is out in the jungle and sees one the thing to do is to take it home, put it in a jar, and wait to see what pops out. I learned about mosquito eggs that way, as a youth I thought they were tadpole eggs, put them in my jar and waited for frogs. Instead I got mosquito larvae and then a jar of dead mosquitos (I didn't take the top off once I recognized the larval form.)
Or maybe set up a camera to take pictures every couple of minutes. Sometimes removing these things from their environment may prevent them from hatching.
The next time the guy is out in the jungle and sees one the thing to do is to take it home, put it in a jar, and wait to see what pops out. I learned about mosquito eggs that way, as a youth I thought they were tadpole eggs, put them in my jar and waited for frogs. Instead I got mosquito larvae and then a jar of dead mosquitos (I didn't take the top off once I recognized the larval form.)