Love is not love which alters when it alteration finds

In 340 B.C., Aristotle noticed that honey bees tend to choose just one flower species during a foraging flight. This behavior, termed flower constancy, continues to puzzle scientists today. Why, when they could select other nearby flowers that are more “rewarding”—offer more nectar—do honey bees, bumble bees, and some butterflies visit only one kind of flower per trip?

Honey bee on camas flower-photo Victor Berthelsdorf

    Flower constancy works out well for flowering plants. Pollen sticks to the bodies of bees and other pollinators as they collect nectar. If the plant is lucky, some of that pollen will be deposited on a flower from the same species. A bee that visits only one flower species per trip is more likely to deposit the right pollen on the next flower, enabling it produce seeds. A fickle insect flitting between different kinds of flowers may just clog the (female) stigma with irrelevant (male) pollen from other species. That explains how flower constancy helps plants. It doesn’t explain what’s in it for the insects.

Does visiting just one flower type help the bee?

    Scientists have come at this from several directions. One theory is that bees don’t have enough short-term memory to retain a schema of more than one flower to visit at a time. Another is that it’s too risky to invest time and cognitive energy into learning to find the nectar in another kind of flower; better to stick with a flower type that the bee knows will provide a good nectar supply. A third hypothesis is that social honey bees avoid conflict with sister bees from their hive by sticking to one kind of flower and leaving the rest for others to visit. 

Honey bees in the hive with their queen-photo Levi Asay

There are problems with each of these theories and a lack of data to support any of them. Bees aren’t as rigid as some of these discussions imply. They’ve been shown to adjust their flower choices when there’s a really juicy high-nectar alternative.

    On Valentine’s Day, I’d like to believe that flower constancy is actually intentional faithfulness. My husband Steve brings me pollen (actually, a whole bouquet of beautiful flowers) every year at this time. He hasn’t gotten sidetracked yet by any high-nectar cuties.

Received for Valentines Day. Bees, eat your hearts out!

    What do we really know about the inner life of bees? Do they have aesthetic tastes in flowers? Do they have other things to think about while they’re sipping nectar and bringing home pollen for their queen’s offspring? In the bee world, females do the work of transporting floral offerings. The males are lounging around the Drones Club between fulfilling their reproductive role.

Drone bee-photo Epgui

    A worker bee only lives for three to six weeks, during which all her labor goes toward the collective good. She’s not going to mate or have children. Maybe she feels alienated at the hive and happiest when she’s out in the sunlight landing on particular flower petals. She could add variety to her trip with a mixture of blooms, but she doesn’t.

Worker bee making her own choices

    Let’s give her some credit for making a strong positive choice. Why just one kind of flower? Because that’s what she wants.