In a remarkable paleontological find, scientists have uncovered the first evidence of ancient bees nesting inside fossilized bones within a limestone cave on the Caribbean island of Hispaniola. This discovery, detailed in a study published recently, points to a previously unknown nesting behavior that challenges conventional understanding of bee ecology.
The cave, known for its rich fossil deposits, served as a nesting ground for giant barn owls over millennia. These predators accumulated thousands of bones from prey such as hutias, large rodents, and other animals, creating a dense fossil record. Over time, sediment filled the cave, preserving these remains in exceptional detail.
During an exploration in 2022, researchers led by Lázaro Viñola-López noticed unusual dirt linings inside the tooth sockets of fossilized bones. Further investigation using CT scans revealed that these were actually small, smooth-lined chambers built by bees. The nests were made of compacted mud and coated with a waxy substance, characteristic of bee nest construction, distinguishing them from wasp nests.
The study, published in the Royal Society Open Science, confirms that this is the first recorded instance of bees using bones as nesting sites. Moreover, nesting in caves is extremely rare for bees, with only one other known case. The bees likely exploited the hollow spaces in fossils, such as empty tooth sockets, which closely matched the size and shape of their natural nesting chambers.
Environmental factors played a key role in this behavior. Much of Hispaniola is composed of karst limestone with little stable soil, making it difficult for burrowing bees to find suitable nesting grounds. The cave offered protected, humid conditions with fine sediment, and the pre-existing fossil cavities provided ready-made shelters. This adaptation demonstrates how bees can innovate in response to ecological constraints.
This discovery fills a significant gap in the fossil record for Caribbean bees, which are otherwise known only from much older amber fossils. It also reveals the ‘hidden biodiversity’ of past ecosystems, where trace fossils like nests can inform about species behaviors even when body fossils are absent. The bee nests have been classified as Osnidum almontei, named after the cave’s discoverer.
Researchers speculate that the bees may have returned to the same cavities multiple times, as evidenced by stacked nesting chambers in some fossils. However, the exact species of bee remains unknown, as the conditions did not preserve their bodies. Future surveys in the area could determine if similar behaviors occur in other caves or if descendant species still exhibit this trait.
Ultimately, this finding underscores the adaptability and evolutionary resilience of bees, which have been navigating environmental changes for millions of years. It serves as a reminder that even well-studied organisms can surprise us with novel behaviors, offering new insights into the complex interplay between life and its surroundings.
