A fascinating study has revealed a unique behavior in ancient insects. Dating back to the Late Ice Age, solitary bees used the bones of extinct mammals to create homes for their young.
Researchers from the Florida Museum of Natural History were excavating Late Quaternary cave deposits in the Dominican Republic, expecting to find typical dental remains in the jaw bones of extinct rodents, as noted in a study published in Publications of the Royal Society. Surprisingly, CT scans showed that these bones contained complex clay nests instead. These structures have been identified as a new trace fossil called Osnidum almontei.
This is the first time anyone has documented bees using unaltered vertebrate remains as nesting places. Such an adaptation highlights how these bees survived in the resource-poor, limestone-rich landscape of ancient Hispaniola.
Archaeologists expected fossil teeth, but they were bee nests
According to the study published in the Publications of the Royal Society, in the province of Pedernales in the Dominican Republic, researchers identified something interesting in Cueva de Mono, a limestone cave.
While digging through late Quaternary sediments, they found the bones of Plagiodontia araeum, an extinct species of rodent known as Hutia. The jawbones held a surprise: Instead of surrounding cave deposits filling tooth cavities, there were clearly mineralized biostructures. At first glance, these teeth looked like ordinary fossilized teeth. However, a closer look revealed them to be complex bee nests placed within bone cavities.
Scans reveal hidden blueprints of ancient architects
Through high-resolution CT scans, researchers have discovered a new species of organism, Osnidum almontei. These archaeological excavations reveal nests with a “Russian doll” or nested cup structure. Bees cleverly use rodent jaw alveoli as protective outer layers for their homes. Within these shells, they create several brood cells stacked in a barrel shape. To build these cells, the bees collected soil and sediment from nearby areas and used biological secretions to bind them to the ceramic-like material once it hardened.
How do bees protect larvae from the humidity of the cave?
The study, published in the Publications of the Royal Society, shows that these solitary bees showed high nesting site fidelity. They keep returning to the same fossilized bones over many generations. Inside the nests, scientists made some interesting discoveries where they found:
- A soft hydrophobic (water-repellent) lining on the inner walls of the cells, likely produced by the bees’ Dufour gland, protects the larvae from the cave’s moisture.
- Clusters of pollen have been found preserved within brood cells, identifying specific ancient plants that bees collected to feed their larvae.
- Some rodent jawbones contain up to six distinct nesting events within a single tooth socket.
Bees replace soil with fossil cavities
The researchers found that this behavior evolved as a way to cope with Hispaniola’s limestone landscape. In these areas, locating soft soil deep enough to dig into the ground regularly is a challenge. However, the bees exploited the natural cavities in vertebrate fossils found on the cave’s clay floors, giving them a safe, stable and climate-controlled environment. This represents the first recorded case of insects using tooth cavities in vertebrate fossils as a nesting site.
