Bees aren’t just builders—they’re also designers. Nest structure differs among species, with one Australian bee stealing the limelight as of late with its unique, spiral-shaped creation.

As Live Science reports, the Australian stingless bee Tetragonula carbonaria captivated the imaginations of Reddit users earlier this month after someone posted a picture of the bees' unusual breeding abodes. Called brood nests, the winding structures house countless individual egg chambers.

Brood nests are multi-storied, and the photo shows just one of its many layers. Experts say that fully developed brood nests can contain anywhere from 10 to 20 circular sections, with each circle hosting hundreds of individual egg chambers. The eggs morph from larvae to pupae to adult bees, and when grown insects leave their cells the remaining ones add to the nest by constructing even more brood cells.

Experts don’t know why Tetragonula carbonaria builds spiral nests. Some researchers suggest that the spirals could be space-efficient and good for air circulation. As they continue to puzzle over the mystery, you can watch Australia's stingless bees in action by watching the video below.

[h/t Live Science]