BY MICHAEL GRESHKO
A NEW FOSSIL find has set paleontologists abuzz: Ancient nests confirm that bees were alive and well in Patagonia 100 million years ago, marking the oldest fossil evidence for modern bees.
The nests, described recently in the journal PLOS ONE, consist of tunnels studded with grape-shaped alcoves, where the ancient bees’ larvae could mature undisturbed. The only group of living insects that builds nests in this particular way is the family Halictidae, a global and highly diverse bee group also known as the sweat bees. Some modern halictid bees build underground nests that look almost exactly like the newfound fossil burrows.
Since it’s unlikely that some unknown animal happened to construct the same nest architecture, researchers are confident that halictid bees built the fossil nests, which were preserved in rocks that formed between 100 and 105 million years ago. The nests are at least several million years older than the next-oldest bee nests, which formed around 94 to 97 million years old, and much older than the oldest definite body fossil of a bee, which is probably no more than 72 million years old.