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These Weird Bagworm Moths Build Log Cabins of Twigs to Live and Die In

Discover the architectural savvy of the bagworm moth as larvae collect materials to build intricate homes from plants.

The nest of a female bagworm.Credit: SIMON SHIM/Shutterstock

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Is that a cluster of miniature Lincoln Logs hanging off a branch? Not quite — what may look like a meticulous assortment of twigs is actually the home of a bagworm moth. These bug architects spend most of their short lives weaving homes out of plant debris.

As larvae, the silky worms find a place to settle down and feed, such as a leaf or the branch of a tree. Then, they crawl around and collect materials like twigs, dirt and dead leaves to add to their homes. The larvae can leave their houses to collect new materials until they’re adults — after that, male bagworms turn into moths, while females remain locked inside forever.

Stick Houses

The worms’ construction process isn’t random. A study of 42 nests from Clania crameri, a bagworm species native to India, showed that the design-savvy bugs use variations of short and long sticks to assemble their dwellings in a meticulous pattern. The larvae collect and assemble sticks of varying length and assemble them in a unique pattern, creating a house that spirals to a tip.

Fully-grown female bagworms remain curled up in their sacks for the rest of their lives. They build a space, mate and then essentially decay into a pile of eggs that will spawn the next generation of larvae. If you see an adult bagworm moth flying free, it’s a male – they appear fuzzy and black, with transparent wings.

(Credit: Will478/Shutterstock)

Will478/Shutterstock

All of this takes place within a few days to weeks. Adult female bagworms live only a few weeks, while their male counterparts have even less time – a male’s life span top out at one to two days.

And not everyone is in awe of the bagworm’s architectural savvy. To many botanists, the bugs are run-of-the-mill pests, known for attaching themselves to plants and stripping them bare of their leaves or needles. But to entomologists, the delicate homes of the bagworm are a marvel.

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