A fossilized jawbone discovered in a cave on the Caribbean island of Hispaniola has yielded evidence of ancient bee nesting. This marks the first documented instance of ancient bees utilizing pre-existing fossil cavities for nesting purposes. The discovery provides insights into the opportunistic nesting behaviors of an extinct bee species.
Discovery Details
The findings involve a newly described species of burrowing bee, Osnidum almontei, which established multi-generational nesting sites within the vacant dental alveoli (tooth sockets) of a fossilized jawbone. Paleontologist Lazaro Viñola Lopez, working with the Florida Museum of Natural History, initiated the discovery by observing an unusually smooth surface inside one of these alveoli during bone excavation.
Jawbone Origin and History
Paleontologists hypothesize that the jawbone originated from an extinct capybara-like rodent, identified as Plagiodontia araeum. It is believed an owl transported the jawbone to the cave after consuming the mammal. Over time, the jawbone's teeth became dislodged, and the bone was subsequently buried in clay silt within the cave environment.
Bee Species and Nesting Behavior
Micro-computed tomography (CT) scans of the host bones confirmed multi-generational use of the same cavities, indicating repeated occupation and a degree of nest fidelity by Osnidum almontei. Nesting fidelity refers to the consistent selection and use of specific nesting sites. Researchers identified numerous similar bee nesting cells, classified as ichnofossils (trace fossils), within various bones found throughout the sediment, including a sloth jawbone. These trace fossils offer insights into the bees' behavior.
The research indicates that Osnidum almontei exhibited opportunistic behavior, utilizing available bony chambers within the sediment deposit for nesting. The high concentration of nests observed suggests that the cave served as a long-term nesting aggregation area for this solitary bee species over an extended period.
The research findings have been published in Royal Society Open Science.