Eyes on bees

The narrative about a decline in honey bees is a modern tale. It is partly a story of agricultural efficiency and the need to feed a growing population. It is partly a story about economic concentration. And it is partly a story about how the public is informed about complex issues, including today’s viral nature of news and competitive views of science.

Yes, honey bees are a complicated story. Think about it. A hive of honey bees represents one of nature’s most fascinating feats—insects organizing and making themselves busy to turn a plant’s reproductive system into food. And that food, honey, is part of human history. No one knows when it first touched human lips, but honey is mentioned in the earliest of written history. It shows up in Sumerian and Babylonian cuneiform and ancient Egyptian texts.

Of course, bees don’t know their status in human history. They’re just, well, busy. And humans have harnessed the bee’s industriousness and made it part of their own. That’s why bees make headlines.

Food production is greatly enhanced by bees, but popular press stories about humanity’s sudden starvation via bee decline are overstated. About a third of what we eat has been affected by the work of bees pollinating crops. Staple crops like rice, wheat and corn are pollinated by air. Thus, for Midwestern farmers focused on cereal grains and corn, bees play a lesser role, but in crops such as cranberries, apples, melons, broccoli and other produce, bees dramatically increase yield. And, some crops such as blueberries and cherries, and especially almonds, are almost wholly dependent on honey bees to pollinate and produce a crop. So whether your crop depends on bees or not, it is easy to see why the public is concerned about bees. They are an integral part of our food system.

It is true the number of beehives in the United States has declined over time, especially if you take a long view. Compared to the days of World War II, when sugar was rationed and people kept hives in the backyard for honey, hive numbers are down. But there has been an increase in hive numbers in more recent years.

In a USDA publication called Beekeeping in the United States, which was written in the 1970s, federal statisticians figured the U.S. bee population at almost 5 million colonies, producing some 200 million to 250 million pounds of honey annually.

For 2014, USDA statistics estimate the number of colonies at 2.74 million, producing 178 million pounds of honey. The 2014 colony count represents an increase for domestic hives. In fact, over the past five years U.S. hive numbers have climbed by 13 percent. According to the Food and Agriculture Organization of the United Nations, since 2000 there has been a 13.2 percent increase in bee colonies worldwide, some 10 million hives worth.

A few factors help explain colony increases both domestically and worldwide. Since Colony Collapse Disorder first became a hot topic a decade ago, and hive numbers fell significantly, beekeepers have redoubled hive management to guard against likely contributors to the disorder. There are occasional weather patterns that increased hive deaths. And then there is economics: honey prices are at record highs. Demand for bees as pollinators is brisk—a growing need for pollinators and fewer hives has pushed hive rental fees to record highs as well. Demand spurs supply.

In their role as pollinators, bees are carted across the United States as seasonal crops create geographical shifts in pollinator demand. The same hives that pollinate blueberries and citrus in Florida can move north to apples and cherries along the Eastern Seaboard. Some bees do a grand tour of western crops, and some do countrywide duty. Total acreage of particular crops has a significant effect on local pollinator bee demand. Californian Almond orchards, for example, have gained acreage in the past decade. Because the crop depends almost entirely on rented bees for pollination, in any given year, more than half of the nation’s commercial hives end up in Californian Almond orchards.

But where did they go?

It was among commercial beekeepers that Colony Collapse Disorder, a non-specific dying off of hives, began to make real headlines back in 2006. What wasn’t covered in the more sensational media stories, though, was the economics of diminished hive numbers that became apparent in subsequent years. According to the California State Beekeeping Association’s annual pollination survey, average almond pollination fees rose from about $54 per hive in 2004 to $151 in 2010. You can see why farmers who depend on commercial bees for pollination began to take bee health more seriously—and why a general alarm was sounded.

Bee deaths from CCD have been attributed to multiple causes. Suspected to be among the most damaging is the parasitic Varroa mite, which is the top pest among bees worldwide. Other parasites and diseases, poor nutrition, stress from travel and pesticide exposure are in play as well.

Varroa mites arrived in the United States in the late 1980s. Tracheal mites are suspected to have arrived here in the early 80s. In fact, in the closing decades of the last century, a number of new bee parasites and diseases came to North America. These relatively new arrivals helped to deepen the mystery of CCD as researchers didn’t have long-term data to show how they affected hives here.

A closer look at neonics

Regardless of the complexity of CCD, environmental groups have been quick to blame bee colony losses on agriculture. From mono-crop production to the use of pesticides, farmers made easy targets to blame for a complex issue. In that capacity, Midwest commodity farmers became a part of the story for their use of neonicotinoid from multiple crop protection manufacturers. Imidacloprid (Gaucho), Thiamethoxam (Cruiser) and Clothianidin (Poncho) are among the neonicotinoids labeled for use in the United States. Worldwide, this class of insecticide has been registered in more than 120 countries. It became popular both for its efficacy and its improved human and environmental safety record compared to older chemistries used to combat the same pests.

In an AgInfomatics meta-study that looked at research conducted over 20 years, neonicotinoid insecticides were shown to have provided average yield increases ranging from 3.6 to 71.3 percent in eight major crops across North America, including all the common crops in the Midwest. Growers in MFA’s territory are familiar with these types of results.

Neonicotinoids, as you might guess from the name, were chemically derived from nicotine. As regulators pushed manufacturers and growers away from harsher insecticides such as organophosphates, researchers turned back to nature’s own defenses. Nicotine, the tobacco plant’s natural defense against herbivores, has been used as a pesticide in the past, but because of its toxicity to humans and instability in the field, scientists engineered neonicotinoids as a safer and more stable alternative.

A study from the University of Maryland published in March 2015 shows that imidacloprid doesn’t significantly harm honey bee colonies at real-world dosage levels.

The study tracked the effects of imidacloprid on honey bee colonies over a three-year period. In the study, scientist had to dose bees with at least four times the amount of the insecticide that they would encounter under normal circumstances to cause significant effects on the colony, including a decrease in winter survival rates.

Leader of the research, Galen Dively, emeritus professor of entomology at UMD, said “Everyone is pointing the finger at these insecticides. If you pull up a search on the Internet, that’s practically all anyone is talking about. This paper says ‘no, it’s not the sole cause. It contributes, but there is a bigger picture.’”

“Imidacloprid is the most widely used insecticide in the world,” said Dively. “It’s not restricted because it is very safe—an order of magnitude safer than organophosphates.” You may recall an extensive campaign against organophosphates that led their removal from domestic markets.

Dively’s study, unlike a frequently challenged Harvard study that has helped fuel the campaign against neonics, used environmental exposure matrices that more closely reflected real-world exposure to evaluate how pollen dosed with imidacloprid would affect honey bee colonies.

In the study, scientists fed bee colonies pesticide-tainted food for as long as 12 weeks, a considerable longer amount of time than pollinators would be exposed to a particular plant’s pollen in real-world scenarios. Still, even at the 12-week exposure period, dosage levels of imidacloprid didn’t cause significant effects on honey bee colonies. With a much higher treatment in the study, a dose some 20 times what they figured to be the real-world exposure, researchers saw more damage to bee health.

While not involved in the study, Dennis vanEngelsdorp, an assistant professor of entomology at UMD, said in a release, “A lot of attention has been paid to neonicotinoids, but there isn’t a lot of field data. This study is among the first to address that gap. It’s not surprising that higher levels will hurt insects. They’re insecticides after all. But this study is saying that neonicotinoids probably aren’t the sole culprit at lower, real-world doses.”

A growing number of scientists, including Dively and vanEngelsdorp suspect that there is a synergistic effect among multiple factors to blame for stress on bee colonies. There is a call for further research to understand the interaction.

In the meantime, there is continued pressure on agriculture. Recently, a federal judge blocked EPA’s approval of Sulfoxaflor in response to a lawsuit filed by the environmental pressure group Earthjustice.

A new cooperation

Regardless of how legal maneuvers go, there will be more research on pollinators. Last year, the Obama Administration, under pressure from environmental groups, beekeepers and various other constituencies announced a pollinator health task force which includes a wide swath of the federal apparatus. In May 2015, the task force released several specific strategies to boost pollinator health including enhancing pollinator habitat on federal lands and finding best management practices that can be promoted among private land owners. The Administration’s stated goals are to cut honey bee colony overwintering losses by half within 10 years and restore or enhance some 7 million acres of land for pollinators over in the next few years. The plan also calls for increasing the number of butterflies that overwinter in Mexico (where they can be counted).

Companies like Bayer CropSciences are working on the issue as well. Bayer, which sells neonic-containing products, has been researching bees for much longer than the current worry about CCD.

Bayer’s focal point for its research in the United States is its North American Bee Care Center, a $2.4 million facility at the company’s North American headquarters in Research Triangle, N.C.

The facility is dedicated to research, education and promoting the kind of partnerships that promulgate best management practices and increased bee forage habitat. Today’s Farmer recently had the opportunity to visit the Bee Care Center. Look for a more in-depth account of that visit, more specifics on pollinators, and how you can get involved in promoting bee health in upcoming issues of Today’s Farmer.