Ancient burrowing bees made their nests in the tooth cavities and vertebrae of dead rodents, scientists discover
More than 5,000 years ago, burrowing bees took up residence in piles of rodent bones buried in a cave on Hispaniola, the Caribbean island that includes the Dominican Republic and Haiti, a new fossil study suggests.
The bees encountered the bones while digging to the desired depth in the soil. They stopped to build nests inside the cavities of teeth and vertebrae, which turned out to be the perfect size, the researchers found. Most of the bones scientists recovered came from hutias – large rodents that look like a cross between squirrels and beavers – but a handful were the remains of a type of extinct sloth.
“The cells of Osnidum almontei [the name given to the fossilized nests] appear very opportunistic, filling all available bone chambers in the sediment deposit,” the researchers wrote in the study.
Bees found the hutia bones long after they were deposited in the cave by Hispaniolan barn owls (Tyto ostologist), postulate the researchers. Evidence shows that these now-extinct owls sometimes carried whole hutias into the cave, discarding the bones as they devoured the rodents, and sometimes regurgitating pellets containing the remains of hutias they had eaten while hunting. Barn owl bones found in the cave indicate that the species lived there, the researchers noted.
These piles of bones were buried over time as sediment entered the cave from outside. And several generations of burrowing bees benefited much later, even though these bees generally make their nests in the open, according to the study.
In one tooth cavity, researchers found six interlocking bee nests, indicating that successive generations took up residence in the same location after previous nests were abandoned.
The bees may have chosen to nest in the cave rather than outside because the surrounding landscape had little or no soil for digging. “The area in which we collected is karstic, so it is made of sharp, wiry limestone, and it has lost all of its natural soils,” co-author of the study. Mitchell Rieglerteaching assistant at the University of Florida, said in a statement.
After one of the scientists’ final visits to the cave, plans were submitted to turn it into a septic installation.
“We had to go on a rescue mission and recover as many fossils as possible,” said the study’s lead author. Lázaro Viñola Lópezpaleobiologist at the Field Museum of Natural History in Chicago, said in the release.
Plans to build a septic tank ultimately failed, but scientists still removed abundant fossils. These fossils have not yet been analyzed, and the team plans to publish more studies of their findings.
