I saw these dogbane moth caterpillars the other day.
They use silk to bind some leaves together in a loose structure, then surround that area by a nearly invisible network of silk. While I was watching, I saw a parasitic wasp (sorry, I don’t know the name of it) investigating. I am pretty sure it would lay an egg on or in one or more of the caterpillars if it could.
While it looks like reaching the caterpillar should be an easy task, while I was watching it was not able to accomplish that goal.
I got chased away by mosquitoes after a few minutes. I don’t know if she succeeded or if she failed, but the nest does at least provide some protection.