Dr. Universe: When was the first bee? – Henry, 7, Illinois
It’s easy to love bees. They are furry and buzzy. Along with other insects, birds and bats, they pollinate about a third of the plants we eat.
I talked about the time bees buzzed around the Earth with my friend Silas Bossert. He is an evolutionary biologist in the Department of Entomology at Washington State University.
“The oldest bee fossil that really is definitely a bee is between 65 and 70 million years old,” Bossert said.
This bee fossil was found in a preserved tree resin called amber. Bossert told me that amber fossils are the best bee fossils because they can preserve the whole bee. But there are also other types of fossils.
Compression fossils are imprints left after something has been squeezed between layers of sediment. It could be the impression of an insect wing. Scientists can use the pattern of veins in a wing print to tell if it was made by a bee.
Fossil tracks are things left behind by an animal. Footprints and fossilized poo are traces of fossils. The same goes for chew marks left in preserved leaves. The fossil record includes leaves with chew marks that resemble the holes made by leafcutter bees. This is a clue that similar bees existed at the time.
Evolutionary biologists also examine DNA evidence. They can compare the DNA of bees from different eras and types of bees to build a map that shows how families of bees are related to each other. This also shows that bees are related to wasps. Bees and wasps share an ancestor: a carnivorous wasp that lived about 130 million years ago.
“Based on this genetic evidence, we think bees are probably around 120 million years old,” Bossert said.
This corresponds to what we know of flowering plants. The plants probably developed flowers shortly before the appearance of bees. Then the flowers flew away once the bees were there to pollinate them.
We don’t know exactly how this ancestor of the wasp gave rise to bees, but here’s an idea. Ancient wasps probably built nests like wasps do today. They probably filled the nests with food that their babies could eat when they hatched – probably some kind of insect since most baby wasps eat meat. It is possible that some wasps have also started leaving small pieces of pollen in the nest. Pollen is full of protein, so it could have been added to bulk up the food the mother placed in the nest. Or it could have been an accident. Maybe the pollen stuck to her hair and then fell into the nest. Eventually, a wasp left nothing but pollen for her babies – just like bees do today. This wasp was the first bee.
Right now, scientists are worried about native bees. These are bees that have always lived here, such as bumblebees and squash bees. They are in danger when their habitats or the plants they eat are lost.
There are things we can do to help native bees. Bossert suggests planting native flowers. Bee lawns also help. These mix flowers like clover with grass to provide food for the bees. Many bees nest underground in dirt or in cavities like hollow stems. Think like a bee! Protect areas that appear to be good nesting sites.
Today there are more than 20,000 species of bees. Scientists discover between 50 and 200 new species of bees each year. Bossert has found and described six new bees himself – and he’s working on more.
Finding new bees is exciting. It also helps us save native bees. After all, the more we know about our neighbors the bees, the better we can protect them.
Adults can help children submit a question at askdruniverse.wsu.edu/ask.