Monday, November 16, 2009

He didn't really say that...did he?

An invitational editorial first appearing in the newsletter of the British Bee Keepers Association
Keith S. Delaplane, Professor, Dept. Entomology, University of Georgia, Athens, GA 30602 USA

This sounds presumptuous, doesn’t it? I mean, lumping bees alongside weighty stuff like survival of the human race. But the fact is, associations like this do get bantered about, especially in times like ours when the welfare of pollinators is a hot topic. Politicians, taxpayers, and agriculturalists are asking, so, just how important are bees? For the most part, beekeepers have been quick to take a high view on this question. And no doubt, one of the rewarding things about working with honey bees is the fact that they are important. Important at the human scale – not just important to me or my fellow beekeepers, but important to the quality of life enjoyed by beneficiaries of developed economies the world over. This importance does not hang on honey production, but pollination - nothing less than our food supply. So it is with pardonable pride that beekeepers have been known to endorse quotes like the one attributed to Albert Einstein: “If the bee disappears from the surface of the Earth, man would have no more than four years left to live.”

Now I must quickly say that there is no good evidence that Albert Einstein actually said this. In fact he most assuredly did not. All you have to do is google “Einstein bees,” and you’ll get the whole story: how this quote surfaced for the first time in the early 1990s, long after Einstein’s death, and in contexts far removed from the possibility of verification. Moreover, one must note the fact that, genius though he was, Albert was a physicist, not an entomologist, and everyone knows that it’s entomologists who are the real authorities on this matter.

But the question implied in this pseudo-quote still stands: is it true that human life depends on bee pollination? Or, more precisely, to what extent does the quality of human life depend on bee pollination? These are legitimate questions, and it’s in everyone’s best interest to promulgate answers based on good biology and economics, not hyperbole, anecdote, or - as the Einstein pseudo-quote warns us - fiction.

It should come as no surprise to learn that the burgeoning interest in pollinators has led to renewed attention to these higher-order questions. And, as is so often the case, when one delves into a biologic/economic system the whole is revealed to be more complex, not less, than originally understood. If I were to summarize the latest answers to the questions above, it would be something like this: Does human life depend on bee pollination? No. To what extent does the quality of human life depend on bee pollination? Well, it depends on where you live and what crops we’re talking about.

If there were awards for the most-quoted article in the pollination canon, it would have to go to S.E. McGregor for his 1976 statement that, “it appears that perhaps one-third of our total diet is dependent, directly or indirectly, upon insect-pollinated plants.[i]” This is the proof text behind the popular paraphrase, “honey bees are responsible for every third bite of food we eat.” I suspect that even in 1976 this estimate was generous and applicable only to the most affluent economies where hay-powered beef and dairy products, oilseeds, and fruits make up a significant fraction of the diet. What seems certain is that this estimate is not global. A recent analysis[ii] of yearly crop data maintained by the United Nations Food and Agriculture Organization (FAO) from 1961 to 2006 reached some divergent conclusions and shed light on the interacting complexity of the question “How important is animal-vectored pollination?”
The authors of the FAO analysis concluded that the proportion of global food production attributable to animal pollination ranges from 5% in industrialized nations to 8% in the developing world. These numbers are in stark contrast with McGregor and can be explained by the fact that his and other earlier estimates tended to minimize the degree to which crops vary in their dependence on animal pollinators. About 75% of the world’s crops benefit to some degree from animal pollination; only 10% of that 75% depend fully on animal pollination. A second explanation is that pollinator-dependent crops tend to have lower average production levels than non-pollinated crops. One can summarize from this paper that most of the calories that sustain human life derive from non-pollinator-dependent crops. This in no way denigrates the importance of pollination at the local level. One need only imagine the economic fallout of a pollinator crash on the California almond industry or Costa Rican coffee. But is it true, sensu stricto, that human life depends on bee pollination? No.

But there is another mega-trend at work, and that is that global demand for animal-pollinated crops is increasing faster than the demand for non-pollinated staples. The fraction of total production made up of animal-pollinated crops grew from 3.6% in 1961 to 6.1% in 2006, and even these statistics mask a huge jump in the years since 1990[iii]. In other words, more people around Planet Earth want ice cream, blueberry tarts, watermelon, almond chocolate bars, coffee, and yes McDonald’s hamburgers - and the trend shows no sign of slowing. So, to what extent does the quality of human life depend on bee pollination? I would say a lot - if you are fortunate enough to live in an economy where bee-pollinated crops make up a significant fraction of what one considers a “normal” diet. There’s one more twist to this tale that highlights the interacting complexity involved in appraising this issue. Over the last few decades more of the world’s food production has been shifting to developing countries. Because of the comparatively low productivity of pollinated crops, in the face of increasing world demand there will be pressure to make up those yield increases by bringing more land into agricultural production. Insofar as environmental protection is weak in these areas there is justifiable concern over deforestation and habitat loss. One way to resist this tide is to invest in large and sustainable pollinator populations so that pollination is not a yield-limiting factor.

In conclusion, I suggest that what’s at stake here is not something so melodramatic as Einstein’s fictitious and dire warning about the collapse of Homo sapiens. I think bee advocates do their cause a disservice when they stoke the flames of hyperbole and sensationalism. Much better to pose the question as a quality of life issue. To the extent that we value a diverse food supply with minimized trauma to the environments where it is produced, we will place a high value indeed on honey bees and other pollinators.

i. McGregor, S.E. 1976. Insect pollination of cultivated crop plants. USDA Agric. Handbook 496, p. 1
ii. Aizen, M.A. et al. 2009. How much does agriculture depend on pollinators? Lessons from long-term trends in crop production. Annals of Botany doi:10.1093/aob/mcp076
iii. 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 doi 10.1016/j.cub.2009.03.071

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