Brainy Bumble Bees

Bumble bee and jewelweed. © Beatriz Moisset

Some of your garden visitors are undeniably clever. Raccoons and squirrels come immediately to mind. But, bumble bees? How could pinheaded insects be capable of any intelligence? Those who study insects tell us that some are capable of remembering things and, even more amazingly, of learning new things and acting accordingly.

The one that gained a reputation as the Einstein of the insect world is the honey bee. Books have been written about its cleverness and the way it communicates with other members of the colony. Some other members of the six legged crowd also show surprising signs of memory and intelligence. Bumble bees, close relatives of honey bees, and also living in colonies composed of a queen and workers, are not far behind them.

If you enjoy spending some time looking at the visitors to your flowers, you may have a chance to see some examples of their braininess.

A tricolored bumble bee, a regular flower visitor
© Beatriz Moisset

Perhaps, one morning you step into your garden, coffee cup in hand, and see a bumble bee on your flowers. The scene looks familiar; you have noticed it several times before. Could it be the very same bumble bee? There is a good chance you are correct. She, and it is usually a she, is good at memorizing the best business locations—the bushes or clusters of plants with abundant flowers and plenty of valuable resources. She is probably guided by a combination of clues to recognize the area: landmarks, the position of the sun, smells, perhaps even the magnetic field of the earth. Thus your friendly garden visitor develops a daily route; and even memorizes the timing of blooming, morning or afternoon to show up right on schedule. Researchers may learn all these things by painting a little dot of color on the back of the bee so they can follow its comings and goings.

Entering a jewelweed © Beatriz Moisset

Another behavior worth watching is their routine when visiting a flower. I love to see them going inside a jewelweed and am always amazed at the speed with which they proceed. I wish they were a little slower and allowed me to take a few pictures. Learning how to deal with complicated flowers takes practice. A naïve bumble bee may refine her technique with time and the more complicated the flower, the more practice is required.

Bumble bee visiting a turtlehead © Beatriz Moisset

Researchers resort to interesting methods to unravel the mysteries of bumble bee behavior. For instance, they glue little tags of different colors to their backs so they can track down the activities of each individual. They test their ability to recognize flowers by offering them artificial flowers of different colors or different aromas; and filling only certain ones with nectar. The student bees learn to choose the flower of the right color or scent and bypass all others.

Enjoy your garden pollinators next season and see if you can recognize these behaviors and perhaps observe new ones.

More on Bumble Bees:

The Telegraph. Might of the bumblebee.Learning tests, yellow flowers vs. blue 

Bumble Bees, Panda Bears of the InsectWorld 

This Way to the Restaurant.

Nectar guides © Beatriz Moisset

Nectar Guides

Most flowers want to make it easy for the visitor to find its way around. Thus, in addition to attracting pollinators with their colors and aromas, they guide their visitors in the right direction. This serves two purposes; it facilitates the task of the pollinator and enables the flower to have its pollen deposited where it is most needed.

Have you noticed the streaks of color radiating from the center of many blossoms? These are the nectar guides that tell the visitor: this is the way to the food. Violets and lupines are good examples. The variety of violets is amazing. We can count more than a hundred species and hybrids. Most of them are native, although a few have been introduced from Europe. As a footnote, it is worth mentioning that some violet species are the food plant of fritillary butterflies.

© Beatriz Moisset 

Don’t you find it rather surprising that the humble violet is the state flower of four states? It would be more correct to say violets, plural. Illinois did not attempt to specify which species, even after giving their flower the name of purple violet to distinguish it from yellow violets. New Jersey and Wisconsin chose the Viola sororia and Rhode Island, Viola palmata. Botanists and horticulturists pay attention to these things. However, legislators often ignore such details. This doesn't matter since all violets exemplify the nectar guides vividly.

Illinois: Purple Violet (Viola)

New Jersey: Common Blue Violet (Viola sororia)

Rhode Island: Violet (Viola palmata)

Wisconsin: Common Blue Violet (Viola sororia)

Texas bluebonnet © Jacopo Werther. Wikicommons

A slightly different type of nectar guides is present in bluebonnets (Lupinus). This Texas state flower includes all the species of bluebonnet that grow in that state. The guides become visible only when the flower opens and becomes receptive to pollinators. Bluebonnets belong to the pea family, Fabaceae, which is valuable to ecosystems because it enriches the soil by fixing nitrogen.

Texas: Texas Bluebonnet (Lupinus spp.)

Bull’s Eye

Some flowers use a different way to guide the pollinator to the desired place. It is called bull's eye. The color of the flower's center contrasts with the rest of the blossom. Several state flowers illustrate variations of this theme. Maryland's black-eyed Susan and Oklahoma's Indian blanket are fine examples. So are Florida's tickseed and Kansas' sunflower.

Sunflower © Beatriz Moisset 

Pollination researchers played a trick on visitors to these flowers to test the hypothesis that the bull's eye helped them find their way. They methodically pulled out all the petals of flowers of this type and glued them back in after reversing their position so that the darker part was in the outside. True enough, bees would land on the blossom, walk to the edge and stick their tongues out in search of nectar. They must have been mighty puzzled and annoyed at finding none.

Indian blanket. © Beatriz Moisset 

Some flowers, such as coreopsis, apparently lack this contrast. They appear uniformly yellow to our eyes. But bees see certain colors that escape us. They can see in the range of ultraviolet light, the so-called black light. The flowers, in turn, have a pattern that becomes visible only under this particular kind of light waves. The flower that appears uniformly yellow to us is seen by a bee as having a black center surrounded by a light halo.

Coreopsis. The bull's eye is visible only under ultraviolet light. © Beatriz Moisset 

Maryland, Florida and Kansas have state flowers with bull's eyes, black-eyed Susan, tickseed, and sunflower, respectively. Oklahoma is rather unusual in having not one but three types of flower symbols: the mistletoe as its floral emblem, the Oklahoma rose as its state flower and the Indian blanket, as its state wildflower. The latter has a conspicuous bull's eye.

Maryland: Black-eyed Susan (Rudbeckia hirta)

Florida (Wildflower): Tickseed (Coreopsis)

Kansas: Sunflower (Helianthus annuus)

Oklahoma (Wildflower): Indian Blanket (Gaillardia pulchella)

This article is about one of the many ways in which flowers increase the efficiency of the pollination process. In the next post we'll see examples of another strategy, frugality.

See: Pollinators of Official State Flowers

References

Black-eyedSusan under ultraviolet light

US National Arboretum. Trees and Flower

State Symbols, USA

Netstate. Official State Flowers

Dowden, Anne O. State Flowers. 1978

Cooper, Jason, The Rourke Guide to State Symbols. Flowers. 1942

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2015