Are you ready for a close-up—a really, really close close-up? The microbes in your mouth probably are and, boy, are they looking fabulous.

Using genetic and fluorescent probes, researchers lit up the ornate structures of microbes that glom onto human teeth. The resulting images and analysis, published in the Proceedings of the National Academy of Sciences, reveal that mouth-dwelling microbes don’t just amass in haphazard globs on the outside of unclean teeth. Instead, the microbes build consistent structures that organize inhabitants into areas where they perform specific functions. The unexpected finding suggests that teeth tenants set up highly ordered and collaborative ecosystems on human choppers.

Those structured ecosystems expose “unanticipated interactions and provides a framework for understanding the organization, metabolism, and systems biology of the microbiome and ultimately, its effect on the health of the human host,” the authors of the study report.

The finding also seems to buck a popular theory among microbiome researchers that suggests that the presence or absence of specific microbes might not be important for the health of the microbial community or the human they inhabit. Rather, the theory goes, the function of those microbes is what’s really important. For instance, if one microbe that makes acetate is missing but is replaced by a different microbe that also makes acetate, the microbial community goes on undisturbed.

But, in the new study, led by Jessica Mark Welch and Gary Borisy at the Marine Biological Laboratory, specific microbes did seem to matter. The researchers found that certain microbes appeared to partner up in functional groups.

For the study, the researchers used toothpicks to carefully harvest clumps of plaque—without disturbing their micron-scale structures—from 22 healthy volunteers who went 12 to 48 hours without cleaning their teeth. Using previously collected genetic data and fluorescent probes, the researchers tagged and imaged nine main genus in the plaque that clings to teeth, namely Corynebacterium, Streptococcus, Porphyromonas, Haemophilus/Aggregatibacter, Neisseriaceae, Fusobacterium, Leptotrichia, Capnocytophaga, and Actinomyces.

The structures the researchers found in nearly all of the participants were what the authors referred to as “hedgehog” and “corncob” structures. The hedgehog structures contained long filaments of Corynebacterium (pink) that stuck to the teeth and stretched out in the mouth in a bushy mass, like spines poking out from the back of a hedgehog. Around those filaments, other microbes grab on and set up niches with various microenvironments. In particular, spheres of Streptococcus (green) at the tips of the filament create corncob structures and a niche that is rich in carbon dioxide, lactate and acetate, and low in oxygen. This creates perfect conditions below for Fusobacterium (yellow) and Leptotrichia (blue) to set up shop.

Whether hedgehog and corncob structures are good or bad for the health of the human requires more research, the authors note.

Proceedings of the National Academy of Sciences, 2015. DOI: 10.1073/pnas.1522149113 (About DOIs).