Floral fidelity yields pure pollen pellets

Flower fidelity makes honey bees special. While many pollinators flit from one plant species to another, honey bees doggedly pursue flowers of a certain species.

So when the new day dawns, Sue and Marianne, Betsy and Josephine grab their flight plans and wing out the front door. Sue is visiting dandelions, Marianne and Betsy are working the apples, and Josephine has cherries in mind. They each collect just one species of pollen. This is great for the plants because the pollen that lands on the stigma is the type needed for fertilization. How this benefits the honey bee is less clear.

Nevertheless, an entire foraging trip will be spent on that single flower type. In fact, individual bees are likely to keep collecting the same pollen for many days. Only when the source dries up does the forager switch to something else.

Floral fidelity is the reason you seldom see honey bees on small plantings. If you have just a little of this and a little of that in your garden, the flowers are more likely to be visited by native pollinators than by honey bees. A honey bee forager wants to see at least two basket-loads of pollen–probably more–before she starts to collect.

Much research has gone into flower fidelity. Examinations of pollen loads show that only about six percent of the pollen is inconsistent with the rest of the load. And some of the six percent may have been introduced accidentally. For example, pollen could have been deposited on a flower by the wind–or perhaps by a different pollinator–where it remained until it was inadvertently picked up by a honey bee.

You don’t need a laboratory analysis of pollen pellets to know flower fidelity exists. Instead, just take a look. Pellets have distinct colors–sundry shades of white, yellow, orange, blue, and gray. Each pellet is made from one color, not mixed up like M&Ms.

Even more interesting, back at the hive the pellets are packed into cells according to type. Although there are some exceptions, the cells are as distinctly colored as mosaic tiles. We see blue ones and red ones, yellow ones and white ones. Whereas nectar is transferred from bee to bee before it is stored, pollen-carrying bees must store their own pellets. Could it be that each forager stores her pollen in the same cell after each trip? Does she know “her” locker from another? I’d like to know more.

The photos of brilliantly-colored pellets were graciously provided by Phillip Cairns at MudSongs.org.

Rusty

An oversized load. Photo by Phillip Cairns

Each pollen pellet has its own distinct color. Photo by Phillip Cairns

Sisters in blue. Photo by Phillip Cairns