These strcutures are called cases, and bagworm moths are also known as “case moths.
The cocoon of the bagworm moth looks like a tiny log house.
The case has another, smaller opening at the bottom.
The caterpillar comes out from the top to feed and ejects the waste from the bottom end.
The bottom opening is also the exit hatch for the emerging adult.
As the bagworm grows, it expands its case by adding more twigs to the top.
They then disappear inside to cut a slit where they plan to attach the new stick.
Photo credit:Biswas.rishov/Wikimedia
The cases of the bagworm moth are incredibly tough and very difficult to break open.
Bagworm cases range in size from less than 1 cm to 15 cm among some tropical species.
Each species makes a distinctive looking case.
Bagworm moths spend most of their lives in the caterpillar phase, and hence inside the case.
After they mate, the females lay their fertilized eggs in their old bags.
Once the larvae hatch, they will create their own tiny log house.
