Bees are frequently associated with large queen-serving colonies featuring hundreds if not thousands of insects. In actuality, that’s usually not the case.“Most bees are solitary. They lay their eggs in small cavities, and they leave pollen for the larvae to eat,” explained paleontologist Laza sro Viñola López. “Some bee species burrow holes in wood or in the ground, or use empty structures for nests.” Viñola López, a researcher at Chicago’s Field Museum, added that some European and African species even construct nests inside vacant snail shells. That said, a beehive inside a bone is a new one even for seasoned researchers. Estimated to be around 20,000 years old, this newly discovered specimen is also the first known example of such a home, past or present. The findings are detailed in a study published on December 16 in the journal Royal Society Open Science. Researchers located the unique find while exploring the many limestone caves that dot the southern Dominican Republic. Sinkholes are common across the Caribbean island of Hispaniola, and are often so well sheltered from the elements that they function like underground time capsules. Generations of owls likely lived inside the caves, leaving their prey’s bones behind. Credit: Lazaro Viñola López. These windows into the past are largely thanks to the work of the island’s owls. The predatory birds often make their nests inside these caves, where they regularly cough up owl pellets filled with the undigested bones of their prey. Over thousands of years, these layers of bones fossilize atop one another across carbonate layers created from rainy periods. Getting a firsthand look at these remnants isn’t for the faint of heart, however. “The initial descent into the cave isn’t too deep–we would tie a rope to the side and then rappel down,” Viñola López said. “If you go in at night, you see the eyes of the tarantulas that live inside.” After proceeding past the large spiders through about 33 feet of underground tunnel, the paleontologists began finding various fossils. Many belonged to rodents, but there were also bones from birds, reptiles, and even sloths for a total of over 50 different animal species. “We think that this was a cave where owls lived for many generations, maybe for hundreds or thousands of years,” said Viñola López. “The owls would go out and hunt, and then come back to the cave and throw up pellets. We [found] fossils of the animals that they ate, fossils from the owls themselves, and even some turtles and crocodiles who might have fallen into the cave.” While cleaning his finds, Viñola López noticed smooth, almost concave sediment within one of the tooth sockets of a mammal jaw fossil. Dirt doesn’t normally accumulate that way in fossils, but then Viñola López started finding additional examples. “I was like, ‘Okay, there’s something weird here,’” he remembered. An illustration showing the bones and bee nests in the cave. Credit: Jorge Mario Macho / Machuky Paleoart The mystery fillings reminded Viñola López of certain fossilized wasp cocoons he examined while on an undergraduate dig in Montana. After CT scanning the specimens, his team noticed that the sediment structures looked nearly identical to the fossils from his college days. Some even still featured pollen grains mother bees likely encased in the individual nests as food for their larvae. Although the nests didn’t contain any fossilized insects, that was to be expected. The caves, while protected from the outside world, are still extremely humid and warm—conditions not suitable for preserving delicate exoskeletons. “Since we didn’t find any of the bees’ bodies, it’s possible that they belonged to a species that’s still alive today— there’s very little known about the ecology of many of the bees on these islands,” Viñola López said. The fossilized bone nests are the first of their kind ever discovered, even across today’s ecosystems. More examples may be out there, but it’s also possible that the caves offered a unique environment for the bees. Without much soil on top of the region’s limestone, the insects may have resorted to caves for nesting. There, the owls’ discarded bones provided a convenient alternative home for the bee larvae. “This discovery shows how weird bees can be—they can surprise you,” said Viñola López. “But it also shows that when you’re looking at fossils, you have to be very careful.” The post Ancient bees laid eggs inside bones appeared first on Popular Science. ...read more read less