The Oldest Bee

The oldest bee ever found, a preserved 100 million year old amber, has been discovered in a mine in the Hukawng Valley of Northern Myanmar (Burma).

The fossil, a quarter inch long, proceeds at least with 35-45 million years any other known bee fossil and it has been given its own family status, Melittosphecidae and a species name, Melittosphex burmensis. As the fossil shares both bees and wasps traits, it supports the theory that pollen-collecting bees evolved from meat-eating wasps. "This is the oldest known bee we've ever been able to identify, and it shares some of the features of wasps," said George Poinar, a professor of zoology at Oregon State University and international expert in the study of life forms preserved in ancient amber.

"But overall it's more bee than wasp, and gives us a pretty good idea of when these two types of insects were separating on their evolutionary paths."

"Just as important, Poinar said, the discovery points to the mechanism that could have allowed for the rapid expansion and diversity of flowering plants around that time - the "angiosperms" that depend on some mechanism other than wind to spread their seeds. Prior to that, the world was dominated by "gymnosperms," largely conifer trees, which used wind for pollination and re-seeding."

These shifts in Earth's vegetation took place during the Cretaceous Period (145.5 million to 65.5 million years ago), the top age of the dinosaurs. The first angiosperms start spreading rapidly about 100 millions years ago, a time corresponding with the data provided by the new fossils which track bees by the same period. "Flowering plants can reproduce more quickly, develop more genetic diversity, spread more easily and move into new habitats. But prior to the evolution of bees they didn't have any strong mechanism to spread their pollen, only a few flies and beetles that didn't go very far." said Poinar.

They account for practically all of the food plants on terrestrial ecosystems and much of the food supply for humans. Now, they've got 20,000 bee species physically and behaviorally adapted to be the most effective pollinators. Wasp traits found in the fossil are a double spine on the middle tibia and narrow hind legs. But it presents clear bee traits, such as branched hairs all over its body (these hairs allows pollen collection) and others key bee features. "In archaeology, a lot of people look at the species Archaeopteryx, which is believed to be the first bird and was sort of half-bird, half-reptile," Poinar said.

"Species such as that can be critically important in helping us to understand when evolution went in different directions. In that sense, this fossil may help us understand when wasps, which were mostly just meat-eating carnivores, turned into bees that could pollinate plants and serve a completely different biological function."

The bee fossil is in remarkable condition, showing individual hairs on undamaged portions of its thorax, legs, abdomen, wings and head. It's very small size constitutes the evidence that the earliest Cretaceous flowers were relatively small.

Amber often preserves some of the most vivid and lifelike glimpses into the long gone eras. Amber, a semiprecious gem, is fossil tree sap, which could trap insects or other small animals, which were ultimately fossilized. As amber has embalming properties, it can protect specimens in nearly perfect, three-dimensional form tens of millions of years.

Photo credit: LiveScience