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 

The Great Impersonators, flower flies

Eristalis tenax, the drone fly, a honey bee mimic

© Beatriz Moisset

Why would one insect want to look like another? There must be some advantage in doing so. When it comes to flower flies the answer becomes apparent after a little observation.

These flies are found visiting flowers rather than garbage or dead meat like some of the flies you are most familiar with. They are rather pretty, with patterns of brown and yellow or black and yellow which easily remind you of bees. I have seen many a photographer deceived to the point of posting a picture of a flower fly claiming that it is a bee.

The goal of this remarkable imitation is not to fool photographers, of course, but rather hungry predators. Flower flies are delicious morsels of food that any bird would readily accept, but the fear of being stung by this bee mimic may lead him to think twice and skip this prey.

Some flower flies are about the size of a honey bee. The mimicry is so convincing that one of them is called the drone fly. Others are smaller and they may be imitating some of the lesser known and very abundant solitary bees. A few are long and thin and look like wasps, rather than bees.

Mallota bautias, a bumble bee mimic

© 2005 Beatriz Moisset

They can be distinguished from bees or wasps by the number of wings. Bees and wasps have four; flies have only two. The back wings have been reduced to little knobs, called halteres, used for balance. The halteres and the number of wings are hard to see when the insect is flitting about. Even when it rests on a flower, you continue to have trouble because a bee's front and back wings hook up appearing like a single unit.

Flower fly (left), bee (right)

Compare the size of the eyes

and the size and placement of the antennae

© Beatriz Moisset

Other differences are more obvious if you train your eye to see them. Flower flies have enormous eyes and tiny antennae that emerge from the front of the head, rather than higher up as in bees. Also flies are almost hairless and their legs are skinny when compared with those of bees. I hope all this helps you and saves you from embarrassing mistakes. I have seen business cards, article illustrations and even a book cover with a fly passing for a bee. So, if you still don't get them right, at least remember that you are in good company.

Toxomerus, mimics of small native bees

© Beatriz Moisset

In England, flower flies are called hover flies, an excellent description of their behavior. Some people in the US are adopting this name, so you may find either term in the growing literature on these interesting and useful insects.

A colorful flower fly

Helophilus, the sun lover

© Beatriz Moisset

These flies feed on nectar; sometimes they also eat pollen, especially the females who need this protein-rich food to produce eggs. This is why they spend so much time visiting flowers. Because of this habit they often end up carrying pollen from one blossom to another. They may not be as good pollinators as bees, but their role is not insignificant and deserves recognition. For instance, the so called drone fly is used to pollinate greenhouse sweet peppers.

Spilomyia sayi, a wasp mimic

© Beatriz Moisset

Let us applaud the bee impostors, flower flies or hover flies, for their role as pollinators.

For more on pollinators and other flower visitors read the e-book:
Beginners Guide to Pollinators and Other Flower Visitors

List of articles

© Beatriz Moisset. 2014

The Importance of Native Pollinators

Bumble bee visiting a sunflower. © 2010 Beatriz Moisset

At the risk of repeating myself, I want to discuss once again the widespread erroneous belief that we depend entirely on honey bees for the pollination of one third of our food and that we would all die if they were to disappear. Honey bees are not the only pollinators. We must value all the others and we should learn to take advantage of them for our crops' pollination.

We must remember that 4,000 species of native bees populate this country; 20,000 the entire world. They vary in size, appearance, season of activity, flower preference. . .  Some live in colonies similar to those of honey bees, but most are solitary and nest in holes in the ground or in hollow tubes inside soft pitted canes or in holes left behind by beetle larvae.

All of them combined are tremendously important, not just for the pollination of wild flowers but also of some crops. In fact, all the crops pollinated by honey bees could be taken care of by one or another of the numerous species of wild bees.

A few examples of the marvelous things native bees do

*Bumble bees and several solitary bees pollinate tomatoes, peppers and eggplants. Only they know how to manage their flowers. Honey bees cannot do it

*The alfalfa bee and the alkali bee pollinate 80% of the alfalfa flowers they visit. Several bumble bees do just as well. The batting average of honey bees is a mere 20%

*A single southern blueberry bee can pollinate $20 worth of blueberries (probably more at current rates). Honey bees don't come even close

Osmia  sp., a mason bee. © 2007 Beatriz Moisset

*An acre of apples can be pollinated by 250 female orchard mason bees. This task would require 1.5 to 2 honey bee hives—approximately 15,000 to 20,000 bees

Squash blossom. © 2014 Beatriz Moisset

*Squash bees are up early in the morning, when squash flowers are at their peak. Later on, when bumble bees and honey bees arrive, most of the pollination has already taken place

*When the weather is bad, too cold or wet, some native pollinators go out anyway. A few work before sunrise or after sunset. The honey bees prefer to stay home under these conditions

An assortment of pollinators provides a degree of insurance. When the population of one species  declines, as it is bound to happen some years, other species take over the slack. This is one of the advantages of diversification. We have depended for too long on just one species.

Despite the advantages of this variety of native pollinators, farmers often resort to honey bees because the wild pollinators are, well, wild, not easily controlled. Honey bees provide a large task force that can be managed and transported where needed. They are perfect for large monocultures, with only one kind of food temporarily available and nothing else the rest of the year.

We shouldn't ignore the contributions of native bees. They can do a superb job at small or medium sized farms. Managing them would require a healthier habitat and less pesticides. A polyculture, the opposite of a monoculture, would also be important.

We are reaching a point in which we cannot rely entirely on just one species of pollinator. The task of changing cultivation practices is huge but it can be done and it needs to be done. The Xerces Society and some universities are committed to developing the ways of putting native pollinators to good use. The results have been highly encouraging.

Long-horned bee on sunflower. © 2007 Beatriz Moisset

 

Additional readings

One Bite our of Three
Don't Underestimate the Native Pollinators

Will We all Die if Honey Bees Disappear?

Bring Back the Native Pollinators! We need them more than Ever

Farming with Pollinators, the Xerces Society
Wild Pollinators, Agriculture’s Forgotten Partners. WildFarm Alliance
Native Pollinators. Wildlife Habitat Council

List of articles
Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2014 

Don't Underestimate the Native Pollinators

Honey bee and several native bees on flowers of fruit trees

© Beatriz Moisset

 The concern for honey bees has exploded in recent years. A day doesn't go by without a new article on the media or comments on numerous nature blogs. Some are agonized cries of help with words such as: Save the bees to save our food supply! Honey bees are going extinct, we are next! Almost completely lost in the shuffle are native pollinators, namely the 4,000 species of bees in the US.

Most of the public is unaware that native pollinators could supply a substantial amount of crop pollination. In many instances one or another native bee or an entire cadre of them results in more efficient pollination than that of honey bees. Here are a few examples:

In an apple orchard, 250 orchard mason bees can do as much as 15,000 to 20,000 honey bees. Squash bees are early risers and are likely to do more pollination of pumpkins and squash than the late arrivals—honey bees and bumble bees. The Southeastern blueberry bee, Habropoda laboriosa, is capable of pollinating $20 worth of blueberries in her lifetime. Many native bees work in wetter or colder weather than honey bees. The alkali bee and the non-native alfalfa leaf cutter bee pollinate a higher percentage of visited flowers than honey bees do. Some small orchards and vegetable fields get most of their pollination done by native bees.

Many native bees practice buzz pollination,

needed by tomatoes and other crops

© Beatriz Moisset

All and all according to some studies, native bees provide $3 billion worth of pollination to agriculture, while honey bees' contribution is valued at $15-18 billion. If we put native bees to work, we could reverse these proportions. Perhaps the best way out of the so-called honey bee crisis is to find the way to take better advantage of the other bees. How difficult would that be?

A hundred years ago native bees played an important role on crop pollination. As far back as seventy or eighty years, several authors noticed that bumble bee and solitary bee populations were dropping. This loss was most noticeable in larger farms where sometimes fruit or vegetable yield suffered by the absence of pollinators. Nobody seemed terribly concerned as long as the honey bee could be brought into service. Some observers knew that native bees were more efficient in many cases, but felt that the ease with which honey bees can be managed compensated for this drawback.

Some native bees are just as efficient as honey bees

at pollinating fruit trees

© Beatriz Moisset

Intensive farming grew as did the need for pesticides, and beehives started to be transported long distances and in large numbers to do their duty. It was the birth of the pollination industry involving beekeeping practices far removed from what would be considered natural. It shouldn't surprise us that such an unsustainable system is causing troubles for honey bees.

Can we bring native pollinators back after they continued to lose ground for the past century? Are there enough left around to take over the task of pollinating our crops? Even without statistics, we can be sure that only a tiny fraction of the previous populations remains. Perhaps, some species are precariously hanging on the verge of extinction or have already disappeared.

Dead solitary bee © Beatriz Moisset

No species takes the road to extinction willingly. Every creature, large or small, fights tooth and nail, or mandible and tarsal claw as the case may be, to stay alive and procreate. A few years ago, an entomologist found a miner bee's nest in a flower pot in his backyard. Another bee expert encountered a rare species of bee, regarded close to extinction, in the very heart of Washington DC, in a butterfly garden at the Washington Mall. With remarkable tenacity, these little survivors had managed to find just enough resources and shelter to raise their families in the middle of the concrete jungle.

We should not give up hope. Native pollinator populations can be brought back to the levels of yesteryear; perhaps then they can resume pollinating the crops that feed us.

Pollinators. © Beatriz Moisset.

Update, April, 2014. I followed some published reports when I said "native bees provide $3 billion worth of pollination to agriculture, while honey bees' contribution is valued at $15-18 billion." However this may be shortchanging native pollinators. Perhaps they do a lot more. A publication by Claire Kremen states that in California  native pollinators are responsible for $2.4 billions and honey bees for $3.9 billions. In other words, in that state native pollinators are responsible for almost 40% of all agricultural pollination. I will keep searching the truth.


List of articles

One Bite our of Three

Will We all Die if Honey Bees Disappear?

Bring Back the Native Pollinators! We need them more than Ever

Wild pollinators worth up to $2.4billion to farmers, study finds

Reversing threats to native pollinatorcommunities and services

Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2014 

Alfalfa Pollination

Large commercial alfalfa field

requiring managed beehives because of its size

© Vapampidis. Wikicommons

What is the most important insect-pollinated crop? Not a fruit or a vegetable but alfalfa. Yes, alfalfa, not because we consume large amounts of their sprouts, but because cattle needs this food. Thus: no alfalfa, no beef or milk.

This crop was first introduced in California during the gold rush. Alfalfa farming grew from there at a steady pace to what it is today, the third largest crop, after corn and soy bean. A few species of bumble bees and solitary bees took a look at this exotic flower, found it to their liking and proceeded to pollinate it. It wasn't a big leap; this plant's blossoms resemble those of other members of the pea or bean family. The native pollinators were familiar with bean flowers and adapted easily to the new arrival.

Alfalfa blossom. H. © Zel. Wikicommons

Peas, beans, alfalfa, clover and several other plants have butterfly-like (papilionaceous) flowers. The lower petals form an enclosure, shaped like the keel of a boat. This structure holds the sexual parts, the anthers and pistil. When an insect lands on the flower, a trigger mechanism makes it snap open or trip the flower. This is how pollination is accomplished.

Honey bees were not present in California when the earliest fields of alfalfa were cultivated. The first beehive arrived in 1853, just one solitary hive; a few others had died in transit. It took many years for the honey bee populations to build up to significant levels. This didn't matter because the wild bees did an excellent job.

New Zealand wasn't so lucky when it started growing alfalfa to feed the recently introduced cattle. The few native pollinators were stumped by the new flower. They lacked the necessary equipment and dismissed the strange blossoms. Year after year, hay grew luxuriantly, but no seeds. Alfalfa growers resorted to importing a few species of bumble bees from Europe to cut down the expenses of having to buy seed every year. Thus, industrious bumble bees saved the day in that country.

Scotch broom, a papilionaceous flower, being tripped. © Beatriz Moisset

 Honey bees detest the rough treatment alfalfa flowers subject them to and soon learn a trick of their own. They enter the flower from the side and help themselves to nectar without tripping its mechanism. Only naïve, youthful ones pollinate flowers. Despite the honey bees' poor performance, most alfalfa farmers resort to them because of the convenience in using a managed species.

In addition to the honey bee, two other species of alfalfa pollinators are managed to some extent and used commercially. They are the Japanese alfalfa leafcutter bee and the native alkali bee.

The populations of native bees have been severely reduced in the last one hundred years largely because of intensive agriculture. Restoring their numbers and putting them to work in alfalfa fields would be an arduous task but a worthy one. Some farmers find that, when they include flowering and nesting site places in their fields or orchards, the health of the crop improves and the need for pesticides diminishes. Thus, alfalfa pollination could be done entirely and more efficiently by native bees. This form of agriculture would be more sustainable than the present methods.

List of articles
Bring Back the Native Pollinators
Will We all Die if Honey Bees Disappear?
Growing Insects: Farmers Can Help to Bring Back Pollinators
Organic Farming for Bees

Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2014

Beginners Guide to Pollinators

Read the review by Kathy Keatley Garvey at the Bug Squad website, For Beginners, a Guide to Pollinators

So many flowers.  So many pollinators. So many floral visitors.
On every field trip, we see something new and different.
With so much interest in pollinators, it's good to see that biologist Beatriz Moisset has written a downloadable book, "A Beginners Guide to Pollinators and other Flower Visitors." It's meant for young adults and beginners.

Beginners Guide to Pollinators and other Flower Visitors available at:

Barnes & Noble
Lulu.com

iTunes
Amazon 

Native Bees, Honey Bees and Natural Areas

Spring beauty bee © Beatriz Moisset

It is common practice for nature centers to have a beehive. Often, a glass wall allows observation of the colony's busy life, seldom failing to catch the eye of visitors. This serves an educational purpose by providing a great opportunity for a behind-the-scenes peek at the private lives of honey bees. Thus, visitors learn about these useful insects and their role as crop pollinators.

Honey bee © Beatriz Moisset

Sometimes I wonder if we are delivering the right message. The purpose of nature centers is to protect natural wildlife and to promote conservation of natural resources. This is clearly stated in many of their mission statements. Honey bees and chickens are domestic animals. They are both important to agriculture. However, we don't keep chickens at the bird feeders to teach about birds. Do we need honey bees to teach about insects?

Nowadays, agriculture relies heavily on honey bees; however, we must bear in mind that honey bees were introduced to this continent by Europeans a few hundred years ago. Until then, all pollination was accomplished by native pollinators, more than 4,000 species of bees and many other insects, such as flies, moths, wasps and even beetles, as well as some birds and bats.

Jack-in-the-pulpit © Beatriz Moisset

Fungus gnats © Beatriz Moisset

Native plants didn't need honey bees then, and they don't need them now. A few examples should suffice. In early spring a number of delicate little flowers carpet the forest floor. They are in a rush to take advantage of the sunlight during the absence of foliage and don’t last long. Thus, they are called "spring ephemerals." None of them is visited by honey bees. In fact, many resort to highly specialized pollinators which have been around for as long as the plants themselves. Skunk cabbage and Jack-in-the-pulpit are pollinated by flies. Spring beauties and trout lilies are visited by an assortment of bees and bumble bees; but get help, in particular, from their own specialized pollinators, the so called spring beauty bee and the trout lily bee respectively.

Azalea bee © Beatriz Moisset

Shortly after, when azaleas bloom another set of specialists comes into service, the buzz pollinators. These are experts at shaking the pollen out of the flower stamens. One of these experts is the azalea Andrena bee. Its name needs no explanation.

So, what are honey bees doing in the meantime? They devote their time to the nectar and pollen of willows and maples. Thus, honey bees make use of these trees, but the trees themselves benefit from an abundance of native pollinators and don't need the extra help. Honey bees also gather pollen from hazelnuts. This is good for the bees but doesn't help the trees in the slightest because they are wind-pollinated.

Magnolia and mordellid beetles © Beatriz Moisset

Honey bees don't pollinate azaleas or rhododendrons. They also ignore dogwoods. As for magnolias and their close relatives, tulip trees, these plants are primarily pollinated by beetles and flies, all of them native. Honey bees are more inclined to visit generalist flowers, the ones receptive to a wide range of pollinators. Therefore, native pollinators are all that the flowers need.

Another problem with honey bees in natural areas is that they may contribute to the spread of non-native plants by pollinating them preferentially. They also may compete with native pollinators for floral resources.

Tricolored bumble bee © Beatriz Moisset

In summary, native plants and native pollinators are members of a complex community. They have adapted to each other and work well together. Honey bees, while important to agriculture, are not needed in natural areas. The only justification for keeping beehives at nature centers is to use them as a gate to the understanding and familiarization with insects and their usefulness. If the visitor leaves the nature center as ignorant of native pollinators as he was when he came in, then the center has failed to deliver the most valuable message of the bees.

It is imperative that naturalists and educators at nature centers with beehives devote time to informing the public about native pollinators and their significance to native plants. Posters with this information would also be helpful.

Augochlora pura © Beatriz Moisset

Tom Bain presents some good suggestions in his blog "GeoEcology. Earth and life through time..."

 "There is an essential piece missing from the typical presentation about pollination in many nature centers, that is the discussion of native pollinators and their essential continuing role in native and not so native ecosystems. Each presentation about honey bees should be accompanied by a hands-on activity to plant native plants that are partners to native pollinators, or the construction of simple solitary bee houses from dry bamboo canes or wood blocks. We would make progress if our children earned great take-home's like solitary bee bundles in place of coloring-in honey bee illustrations; and, planting native seeds to grow purple coneflower or other natives in place of marigolds, etc. A little effort and a subtle change in emphasis would shift attention to native pollinators."

List of Articles

Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2013