The Elements of Evolution (19-1) Pollinating Bees

Pollinating Bees

Well over 150 MYA, some in the apoid lineage of wasps began to change their foraging preferences: abandoning hunting in favor of flowers. Bees evolved to rely entirely on tantalizingly sweet nectar, rich in carbohydrates, and protein-rich pollen.

Early bees resembled their carnivorous wasp cousins, with sleek bodies and short tongues (proboscises). Enticed by nectar and pollen, bees evolved longer tongues. Seeking a captive pollinator to improve fertilization productivity, some flowers developed longer flower tubes that only certain bees could access, as well as specialized signage and accoutrements that attracted the desired clientele. This and other traits occurred in radiation and coevolution of bees and flowers.

Bee bodies became hairier, enabling more efficient pollen collection. Some bees, including honeybees, developed specialized structures, such as brushes and pollen baskets.

Coevolution resulted in some stunning specializations. With a straw-like proboscis, the southeastern blueberry bee feeds mostly on blueberry flowers. This bee’s secret for success comes with its buzz: rapidly vibrating against flowers’ anthers to “buzz” off the pollen, which sticks to the forager’s furry body. The captured pollen feeds brood back home as well as pollinating the next blueberry plant. Mutualism evolved to the extent that these bees are active only in early spring, when blueberry blossoms are abundant.