For healthy bees: Sow seeds, not war

The room was fluttering with bee conservationists. The seats were occupied by men and women from all over the Pacific Northwest who had agreed to donate considerable sums of personal time and money to tramp across the tristate area and survey bumble bees. Butterfly nets, catch jars, and t-shirts were stacked next to doughnuts, coffee, and printed manuals.

About halfway through the classroom training, a women in the back of the room raised her hand. “I have a confession to make,” she said. “I am a beekeeper.”

The temperature in the room dropped ten degrees as a stony silence fell over the attendees. In the silence I became aware of a ventilation fan humming softly in the ceiling and muffled voices in the hallway. A child whined somewhere in the distance. In the frigid room, you could have heard a bee hiccup.

Beekeepers anonymous

The scene reminded me of television depictions of AA meetings, the kind where a courageous person stands in front of the group and admits, “My name is Sue and I’m an alcoholic.” But instead of applause or recognition, this unfortunate woman was met with ice.

I slid lower in my seat and let my hair fall around my face. If I can’t see them, they can’t see me. Right? Although I prefer to attend any kind of bee meeting incognito, at least two people in the room knew me. I held my breath until the silence was broken by the group leader who said, “Thank you for disclosing.”

Disclosing? Really? I wanted to shout, “She’s a beekeeper, not a criminal.” Although I was annoyed, I wasn’t surprised. As someone interested in all types of bees, I’m well aware of this standard response. It’s an “us” versus “them” world, and it’s high time we put a stop to it.

Wrong on both ends

Many bee conservationists believe that beekeepers are the source of all their problems. They claim beekeepers invade pristine acreage, swipe all the available forage, spread disease, and generally displace the native species. For their part, some beekeepers complain that conservationists collude to keep them off the best forage by putting unreasonable restrictions on hive placement.

In my opinion, beekeepers underestimate the value and contribution of native bees, and conservationists overestimate the damage and competition caused by honey bees. There will always be beekeepers, and for the sake of the planet, let’s hope there will always be wild bees. In truth, beekeepers and bee conservationists have common problems and similar interests. Instead of being conclusory and antagonistic, both sides would benefit by working together to make life better for all bees.

Bee on Bee Attack: All bees compete with each other. Here a native bumble bee uses its right front leg to push a native leafcutter bee off a thistle flower. © Rusty Burlew

What bees are we talking about?

I fault both groups for misrepresentation. In North America, most arguments I’ve heard assume there are only two groups: honey bees and native bees. Conservationists seem happy to defend all species of bees except the European honey bee, Apis mellifera. But wait! What about all the other introduced bees?

At least 55 species of bees have been introduced into North America since the honey bee,¹ and I know of at least one more species that isn’t yet listed.² Some of these bees now have massive distributions on the continent, including the alfalfa leafcutting bee, Megachile rotundata, and the horn-faced bee, Osmia cornifrons. Both these bees were introduced to pollinate specific crops, and both easily naturalized into the environment, just like the honey bee.

Most introductions were accidental. Nevertheless, some of those, like the European wool carder, Anthidium manicatum, can now be found in backyards and wildlands from coast to coast. In a few isolated cases, unsuccessful attempts were made to eradicate an introduced bee species, but with little success.³

Impacts of non-native bees

A comprehensive 2016 literature review by Laura Russo of Penn State University¹ examines the impacts of non-native bee species throughout the world. Russo analyzed no less than 450 papers detailing both the positive and negative effects of introduced bees. She concluded that, for the most part, we simply don’t know or understand the impacts, especially since any negative consequences are often offset by positive ones.

Some of the possible negative effects from introduced bees are competition with native bees for forage and habitat, the spread of pathogens and parasites, increased seed set in invasive weeds, and decreased seed set in native plants. On the plus side, introduced species can increase the pollination of agricultural crops, pollinate plants whose native pollinators are in short supply, and can provide pollination buffers against human-induced habitat disturbance and changes in climate.

Many of the consequences of introduced bees, both negative and positive, are hard to prove and even more difficult to measure. The simple presence of introduced bees—including honey bees—doesn’t make them guilty.

Leafcutter domicile: Leafcutter domiciles like this one in a Touchet, Washington alfalfa field can promote infections of chalkbrood disease. In many cases, the mortality rate is so high that new cocoons must be purchased each year. © Rusty Burlew

Competition is normal

Competition always exists when two or more species are dependent on the same resource. If you watch a group of native bees on a patch of flowers, you can see them tussle over territory. They often butt into each other, trying to force each other off the flowers. Add introduced species to the mix and they continue to behave in the same way. It’s what bees do, large and small, native or not.

I’ve heard beekeepers fret over the appearance of wool carder bees that chase their honey bees away from flowers. “It’s not fair!” they insist. “How can we get rid of them?” But their names alone tell you something. The European wool carder bee and the European honey bee are probably just reawakening an old rivalry that began in the homeland, one that existed long before beekeepers. It’s not something to worry about.

Competition changes with the seasons

Not every meal engenders a fight between species. Food selection among bees has a lot to do with tongue length, floral structure, air temperature, the number of available resources, and the sugar content of nectar. For example, honey bees will compete with blue orchard bees, Osmia lignaria, on Siberian squill blossoms, but when the blue orchard bees move over to the pear trees, the honey bees demur. Honey bees are rarely interested in low-sugar nectar that blue orchard bees find attractive.

Similarly, bumble bees fly in colder temperatures than honey bees, giving them first dibs in the early part of the season. And longer tongued bees find plenty of nectar in deep tubular flowers like red clover, which honey bees find difficult to reach.⁴ When many flowers are in bloom, each bee finds her favorites. When few species are available, competition increases for what remains.

Of course, if you drop a truckload of honey bees in a field, competition among bees will increase. But the magnitude of the increase and its impact on native species is hard to determine.

Although it is true that multiple colonies can displace many individual bees, the greatest competition in that situation is likely among the honey bee colonies themselves—all of which are working the same crops and liking the same flowers. The solitary bees, with fewer mouths to feed, can often make do with the scattered weeds that honey bees ignore—a good reason for not spraying roadsides and field borders.

Management makes a difference

In her paper, Russo concluded that the most detrimental aspect of non-native species is the increased spread of exotic diseases and pathogens. Good examples include varroa mites and tracheal mites, both parasites of the honey bee. While these particular parasites seem to be confined to honey bees, other problems arise from their presence. For example, because varroa mites transmit bee viruses among colonies, the ambient level of bee viruses in the environment seems to have increased. These viruses, some of which can be transferred to other bees via flowers, are beginning to show up in species such as bumble bees.⁵

Regardless of a bee’s origin, management practices have an impact on disease spread. A good example is Nosema bombi.⁶ Although this pathogen can be found in isolated museum specimens dating back to 1980, it spread rapidly once we began raising bumble bees for greenhouse pollination. When infected bees escaped into the wild, they distributed the disease to native populations. As a result, the rusty-patched bumble bee is now on the endangered species list, and critical losses are occurring in several closely-related species.

Alfalfa leafcutting bees are an introduced species that suffers from chalkbrood. But as far as we know, chalkbrood occurs only incidentally in wild populations, while it ravages managed populations kept in densely-populated domiciles. Likewise, when native Osmia ligaria are raised in close quarters, they are frequently decimated by the parasitic wasp, Monodontomerous. However, in wild populations where individuals are spread apart, this wasp is only an occasional problem. As many beekeepers can attest, diseases and parasites benefit from large and proximate populations of their favorite host.

Because dense populations of bees are oases for parasites, pathogens, and predators, keepers of bees have a responsibility to control the spread of disease. Regardless of whether a keeper has honey bees, mason bees, leafcutters, or bumble bees, he should understand how out-of-control disease can affect the larger ecosystem.

Monodontomerus: The Monodontomerus parasitic wasps lay their eggs inside the cocoons of Osmia mason bees. Populations of the wasps build up when many mason bees are raised in close proximity to each other. © Rusty Burlew

Taking advantage of what is missing

Although about 70 percent of all bee species live in the ground, fully 77 percent of all the accidentally introduced species live in above-ground cavities. Several reasons come to mind. Objects involved in international trade, including wooden products, basketry, bamboo, shipping crates, pallets, and packing material may contain cavity-nesting bees. These products are much more likely to arrive on our shores than shipments of soil, especially soil containing viable cocoons. On top of that, cavity-nesting adult bees are more likely to find a home in the city where cavities are plentiful, but plots of undisturbed soil are scarce.

According to Russo, the majority of introduced species in North America first became established in the cities. As the ground nesters were displaced due to urbanization, the cavity nesters filled the pollinator void. With so many ground nesters gone, this band of introduced urban pollinators—which includes the honey bee—performs a huge pollination service to urban and residential landscapes. In short, the assortment of urban pollinators has evolved to meet the demands of the urban landscape.

The infamous one-third

Just as conservationists short-change the honey bee, beekeepers routinely overestimate the contributions made by their charges. Dozens of books, movies, blog posts, lectures, articles, and news stories about honey bees in the last ten years began with a variation of the same erroneous statement. “Honey bees pollinate one-third of the human food supply.” This tells you two things. First, beekeepers who write lack creativity. Second, beekeepers who write are not doing their homework.

About nine years ago, I corralled a few people to help me find the source of this rumor. As close as we could come at that time was a quote by Edward O. Wilson in the foreword of the 1996 book, The Forgotten Pollinators. He explains that one-third of our food supply is dependent on flying beasts: “One of every three mouthfuls of food we eat, and of the beverages we drink, are delivered to us roundabout by a volant bestiary of pollinators.”⁷ But a world of difference separates the class “volant bestiary” from the class “honey bees.” The difference includes birds, bats, beetles, butterflies, and moths, not to mention the other 20,000 species of bees. Talk about overstating your case. No wonder beekeepers are a maligned group.

This bending of reality is similar to a game of telephone where the influence of the honey bee inflates as the message is passed along. “Flying animals” becomes “insect pollinators” which later becomes “bee pollinators” until, in the final message, honey bees alone are doing all the work. And don’t get me started on units. When you say one-third of the food supply, do you mean by weight? Volume? Do you mean a third of crop species? Or calories? Nutrients? Monetary value? No one ever says what they are measuring.

Keepers of honey bees need to realize they’re not the only game in town, and a lot of pollination is happening behind their backs. In fact, my vote for North America’s premier pollinator would go to the orange-legged furrow bee, Halictus rubicundus. Found naturally in every state from Alaska to Florida, and across Canada from the Northwest Territories to Quebec, they work silently in the background where no one notices them. I don’t think I’ve ever seen a field or orchard where they weren’t working their stripes off, yet they are seldom seen or credited.

Halictus rubicundus: Although seldom recognized, the orange-legged furrow bee Halictus rubicundus is a tireless pollinator in many agricultural and natural settings. © Rusty Burlew

The size of the bee

The biggest roadblock to understanding pollinators is size. It’s hard to evaluate what you can’t see, and many of the smaller bees are hard to recognize as bees unless you work at it. The smallest bee in North America, Perdita minima, is a little less than 2 mm long, roughly the thickness of a US five-cent coin. Once you picture that length, try to imagine its commensurate width. You get something that looks like a tiny splinter.

Tiny bees do everything that “real” bees do. They collect pollen, drink nectar, mate, build homes, lay eggs, and provision their young. They defend their territory, fight off enemies, and clean their antennae. And all the while, they pollinate like crazy, working big flowers and small. And who gets credit for all this work? You know who.

Full circle

It seems that beekeepers and bee conservationists should stop bickering about who belongs here and spend more energy finding ways to help all bees. From a practical point of view, bees compete not with each other as much as they compete with us. Habitat destruction and lack of forage are problems larger than competition between individual species.

We’ve taken the bees’ environment and paved it, built it, urbanized and polluted it. Then we mowed it, treated it, mulched it, and planted it with grass and evergreens. Then we monitor bee populations and say, “Gee, bees are disappearing. There must be too much competition!” This doesn’t make any sense.

To the chagrin of some conservationists, honey bees are not going anywhere. Our system of agriculture depends on them, and no bee exists that can be used as effectively. Truthfully, I’ve never met a bee conservationist who didn’t eat foods the honey bees make readily available. Conversely, I rarely see a beekeeper who didn’t enjoy a little chocolate or vanilla in their diet, or maybe a tomato or a fig bar, all available due to the hard work of other pollinators.

Taking sides

So if you must take sides, side with the bees. We don’t know all the answers to bee health, but one thing seems clear: healthy bees do better. We can enhance the health of all bees by providing a varied and plentiful diet and by employing beekeeping practices that limit the spread of disease.

So just do it. Go plant some flowers. And remember that although a small garden or a few potted plants won’t feed a colony of honey bees, it can mean life or death for something the size of a fruit fly. And since our bees harvest from our neighbors’ lands, both public and private, the least we can do is pay back in flowers.

Rusty
Honey Bee Suite

References

1  Russo, L. 2016. Positive and Negative Impacts of Non-Native Bee Species Around the World. Insects, 7(4), 69. http://doi. org/10.3390/insects7040069.

2  Another wool carder bee, Anthidium florentinum, was recently found in Montreal. See Normandin E, Vereecken NJ, Buddle CM, Fournier V. 2017. Taxonomic and functional trait diversity of wild bees in different urban settings. PeerJ 5:e3051 https://doi.org/10.7717/peerj.3051

3  Wenner A, Thorp R, Barthell J. 2008. Biological control and eradication of feral honey bee colonies on Santa Cruz Island, California: A summary. In Proceedings of the 7th California Islands Symposium Institute For Wildlife Studies, Wildlife Studies, Arcata, CA, USA (2) 5–8.

4  Red clover, Trifolium pratense, is frequently confused with crimson clover, Trifolium incarnatum. Crimson clover is a great honey bee plant but red clover, not so much.

5  Dolezal AG, Hendrix SD, Scavo NA, Carrillo-Tripp J, Harris MA, Wheelock MJ, Toth AL. 2016. Honey Bee Viruses in Wild Bees: Viral Prevalence, Loads, and Experimental Inoculation. PLoS ONE, 11(11), e0166190. http://doi.org/10.1371/ journal.pone.0166190

6  Cameron SA, Lim HC, Lozier JD, Duennes MA, Thorp R. 2016. Test of the invasive pathogen hypothesis of bumble bee decline in North America. Proceedings of the National Academy of Sciences: 113 (16) 4386-4391; DOI: 10.1073/pnas.1525266113.

7  Buchmann SL, Nabhan GP. 1996. The Forgotten Pollinators. Washington, DC. Island Press.