Monday, May 10, 2010

The Secret Life of Bees and the Scoping Problem

This is the second in a series of posts devoted to food.

A honeybee on an apiary, cooling by flapping its wings. Location: Tübingen-Hagelloch.
(Wikimedia Commons)

In the last quarter of 2006, a massive die-off, or more accurately complete disappearance, of North American honeybees alarmed beekeepers, farmers, agricultural departments and academics nationwide. When reports started to make it to the mainstream media that honeybees were disappearing, in vast numbers, and at an alarming rate, the idea that the population of honeybees had dropped by more than 30% in major agricultural areas was not at first put into context by the general public. It's easy to do that though, with the reporting of one simple fact: 90 common crops in the continental US require honeybee pollination. A honeybee does over the course of an hour what it would take a human many, many hours, if not days, to do by hand. Commercial monetary value of bee pollination is in the range of $15-20B a year. Crops that are bee-pollinated (some crops are wind-pollinated) include a vast majority of fruits, vegetables and nuts, and also notably, the majority of common livestock feed crops like alfalfa, clovers and vetches. You can get a fuller picture of what's involved here. When you look at the extent to which the world is dependent upon these ardent little creatures for its meals, you can easily see why even the relatively anti-science Bush administration went into overdrive trying to figure out why bees had literally disappeared overnight. Because beekeepers weren't reporting a bunch of dead bees that you could do necropsies on. Their bees were just plain gone. (Some beekeepers report losses of up to 90% of their bees, leaving only young and poorly skilled worker bees who could not survive and thrive on their own.) The majority of states in the continental US have been affected by what is now termed Colony Collapse Disorder (CCD). Mobile or migratory beekeepers who run commercial crop pollination services have reported alarming bee colony die-off and disappearances in the following states:

The hallmarks of CCD include: rapid loss of adult worker bees, few or no dead bees found in the hive, presence of immature bees in a small cluster with live queen present, and ample pollen and honey stores in hive. This means the worker bees have disappeared leaving behind what appears to be a healthy hive with immature bees and their queen. It's like they went out for pollen and never came back. Where have these bees gone and what is their fate? No one knows.

James McWilliams, who blogs for the NY Times under the Freakonomics banner, had an insightful and informative post just last month about the complexities of the honeybee decline. He cites the recent Congressional Research Service report on the topic. The stressors brought to bear on bees are varied and there is no one simple factor that appears to be the "answer" on the issue of CCD. Among the factors that appear to be significant are infestation of the bee population with Varroa mites, or the pathogenic fungus Nosema ceranae,  viruses such as the devastating Israeli Acute Paralysis Virus (IAPV), which is believed to be transmitted by a Varroa mite vector, poor nutrition due to apiary overcrowding, pollination of crops with low nutritional value, or pollen or nectar scarcity; exposure to limited or contaminated water supplies; and migratory stress due to beekeeper overuse of mobile colonies. (Thus far, IAPV is one marker most strongly associated with CCD.) Unlike prior bee losses in the US, CCD represents a sudden and dramatic disappearance. In the course of three to four months, entire colonies have been wiped out and disappeared, leaving growers of bee-pollinated crops scrambling to find commercial beekeepers with viable bees to pollinate. Some studies have shown that irradiating the apiaries with ultraviolet spectrum light to kill pathogens has permitted some colonies to recover.It hasn't worked in all cases and it's not clear that a single or even any pathogen is involved in CCD, however.

The reality is that after intensive research, more than three and a half years later, we are still no closer to understanding CCD with any certainty. In fact, while colonies of bees continue to be decimated at alarming rates in the US and Europe, in other areas of the world, bees populations appear to be increasing. Argentine scientists Marcelo Aizen and Lawrence Harder have shown that worldwide, the population of commercial honeybees has actually increased by some 45% over the past fifty years.2 Futhermore, production and yield of bee-pollinated crops have kept pace with the increased production and yield of wind-pollinated crops. You'd expect a fall off in those values if there were really fewer bees. And yet... and yet... the alarms are real. The number of beekeepers in Washington State has fallen from forty-five to only eight as of 2010.3 The trend of fewer beekeepers in the US, and in agricultural areas is a point of  concern.

The real crisis of crop pollination may have, in the long-term, less to do with CCD and more to do with the global demand for luxury crops that demand pollination. The 'scoping' problem,3 focusing on the narrow or microscopic picture, misleads us by focusing on the bees themselves instead of taking the broader view (the telescopic view) of what we're asking the bees to do. While honeybees producing honey have largely been outsourced to Asia and to a lesser extent Latin America, fewer beekeepers remain in the US and those are largely the commercial and migratory beekeepers. Wind-pollinated crops like wheat, corn and and potatoes have doubled, however the production of bee-pollinated crops has quadrupled worldwide. That 45% increase in the honeybee population thus pales in comparison to the task set before the pollinating bees, a 400% increase in the number of crops they are to pollinate.4 The first world craving for watermelon in winter and more and more chocolate and fancy nuts is fueling the increasing demand for pollinators. And yet fewer and fewer honey producers, and therefore commercial beekeepers, are based in the US and Latin America in the agricultural areas that produce these fancy products. Here in the US we get a large amount of out-of-season food from Latin America (plums in December anyone?) where Marcelo Aizen notes that bees are still, thankfully, largely unaffected by CCD. 

What will happen if or when the complex cause of CCD becomes a worldwide phenomenon? As  Nathanael Johnson, in his article for Conservation Magazine says, "In the process of demonstrating that no global pollinator crisis was occurring, Aizen and Harder found the portents of, well, a global pollination crisis. However, the crisis they foresee is one driven not by mysterious die-offs but by market pressures plainly visible in the produce aisle. It has to do with people in poor nations developing an appetite for good cocoa and coffee. It has to do with people in wealthy countries assuming that tomatoes will be ripe and readily available year-round. Bee scarcity, in other words, is an economic problem caused by economic forces."3

What comes to mind is that we are getting to be too many people, eating things that we never really give much thought to, on a very crowded and rather disordered planet. Portents, indeed...

Parents may enjoy sharing the site: with their children.

1. K. Ramanujan, “Parasites, pathogens and pesticides called possible suspects in honeybee decimation,” Cornell Chronicle, Cornell University, May 17, 2007,
2.Aizen, M.A. et al. 2008. Long-term global trends in crop yield and production reveal no current pollination shortage but increasing pollinator dependency. Current Biology 18:1572–1575.
3. by Nathanael Johnson.
4. Aizen, M.A. and L.D. Harder. 2009. The global stock of domesticated honey bees Is growing slower than agricultural demand for pollination. Current Biology 19:915–918.

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