The Origin of Bees

Scientists have concluded that all the world's bees evolved from the wasp family Crabronidae, or from their common ancestor. They put the major divergence at over 100 million years ago, which would seem to give ample time for defining characteristics to come and go, especially considering the spectacularly recent, tiny, and complex epoch of human development.

The photos below portray contemporary members of the Crabronidae family at Halibut Point.

Sand Wasp, Clitemnestra bipunctata, with prey

The bees' waspy ancestors (and their current wasp cousins) are predatory. They provide animals, generally other insects, for their young to eat.

Aphid Wasp of the tribe Psenini, with prey

These provisions are often in the form of paralyzed prey for consumption by the larvae in the nest, or as eggs inserted into a living caterpillar to develop at the host's expense and eventual demise.

Beewolf, Philanthus bilunatus

Those carnivorous proteins are necessary for the development of the newborn stage. Meanwhile the diet of adult wasps is generally vegetarian.

Jewel Beetle Wasp, Cerceris fumipennis

Bees, on the other hand, are entirely vegetarian. They switched to feeding their babies plant pollen. It's easy to find and it doesn't fight back. Pollen is rich in proteins, amino acids, and fats, with some carbohydrates included as well. The bulk of their carbohydrate needs for fuel comes from flower nectar, which may be converted to and stored as honey.

American Sand Wasp, Bembix americana

Pollen also happens to be the flower's equivalent of sperm, setting up a fine opportunity for a mutually beneficial relationship. Plants are immobile, which complicates their sex life a bit. To mix up their DNA and avoid inbreeding, plants need to move that pollen around. For much of their history since colonizing the land, wind has been the primary dispersing agent of pollen. Plenty of plants such as grasses and pine trees still do it that way. 

Astata unicolor wasp of the Crabronidae family
nectaring on smartweed flowers

In our present era somewhere in the neighborhood of ninety percent of all flowering plants are thought to receive pollination services from animals ranging from lemurs, bats, and birds to moths, beetles, and flies. But it is bees that have evolved to be the star pollinators. They didn't just happen on a ready-made botanical world. Flowers as we know them, and much of our agriculturally-based diet, owe their form and existence to collaboration with bees.