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By Jeff Danner Jeff has worked in both the chemical and biotech industries and is the veteran of thousands of science debates at cocktail parties and holiday dinners across the nation. In his Common Science blog, Jeff aims to make technological and scientific concepts accessible to all.

The Vanishing of the Bees Part I: Psychology

By Jeff Danner Posted April 20, 2014 at 3:35 pm

I have been considering writing about the importance of honeybees and their mysterious and troubling population decline for some time, but have been waiting for an aspect of the story that I thought needed further exploration. Now I have found two: the psychology which we apply in complex situations like this, and how I think local policy should be guided by the science underlying this issue. Also bringing the subject to mind is my scheduled pick up of two packages of bees for hives on my farm this weekend. First, let me summarize the importance of the honeybee and lay out some details of their current plight.

Approximately 90% of wild plants as well as the plants that account for 30%(1) of the food calories that humans consume require pollination, the transfer of pollen from a male to a female flower, to prosper and reproduce. Important food crops that are dependent on pollination include almonds, berries, tomatoes, soy beans, melons, fruit trees, broccoli, avocados and many others.

Pollination is carried out by bees, wasps, hornets, butterflies, hummingbirds, and bats as well as by the wind. Due to the features of its body and the particulars of its habits, the honey bee is by far the most efficient of the pollinators. Due to their prowess as pollinators, honey bees have been raised and managed by farmers for thousands of years. For example, during the time of the Egyptian empires, bee hives were ferried up and down the Nile River to follow the crops. Just as in ancient Egypt, honey bees are transported all over the United States every year. It has been estimated that the pollination services provided by the honeybees are worth approximately 15 billion dollars a year to U.S. food producers.

Then, in 2007, things began to go horribly wrong. Beekeepers across the U.S. began reporting the loss of 30 to 70% of their hives over the winter. In addition to this rate being much higher than normal, the manner in which the hives were lost was strange and rather eerie. One day a hive would be thriving, and only a few days later it would be nearly empty, with only the queen and a scattering of young bees left. A hive in this situation will soon die off completely. Further, the dead bees couldn’t be found anywhere. They just seemed to disappear. Scientists named the phenomena Colony Collapse Disorder (or CCD for short). Beekeepers can partially mitigate the losses from CCD by splitting hives in two and ensuring that both halves have a queen. However, they can’t keep up. Estimates are that there are 25% fewer commercial bee hives now compared to the mid 1990s. Wild bee populations are down significantly as well.

The investigation and public discussion regarding CCD brings me to the first point on this subject which I believe warrants additional exploration: our group response to complex problems. I call it the “search for the smoking gun.” Nearly every public discussion of the struggles of the honey bee looks for a single, well-defined root cause for CCD, with the thought being that finding this single cause will provide an easy fix. A partial list of the possible smoking guns which have been studied is below:

• Mite infestation.
• Fungal infection.
• Viral infection.
• The rise of monumentally large monoculture farming operations which, due to only having one type of plant, only bloom one or two weeks a year, which means that for the rest of the year there is no food for the bees.
• The transformation of suburbia into a grass and concrete-filled expanse with no food for bees.
• Global warming changing the timing of plant blooms so the food isn’t at the right time and place for the bees.
• Loss of genetic diversity and robustness of the bees due to overly intrusive human management and in-breeding. (2)
• The stress caused by being transported cross-country by tractor trailer.
• The use of a class of systemic pesticides called neonicotinoids by farmers.

At present, much of the reporting on CCD is focused on neonicotinoids, which are pesticides that are applied to seeds prior to planting and which then get incorporated into the leaves and flowers of the resulting plant while it grows. There have been several recent studies which suggest that the exposure that bees receive to these chemicals causes a weakening of their immune systems, making them more susceptible to a variety of diseases and perhaps impairing their ability to navigate. The use of neonicotinoids has been banned in several European countries.

So are neonicotinoids the smoking gun for CCD? Perhaps, but let me explain why I am skeptical. Collectively, when we observe sudden change, we humans tend to assume that it must arise from a single cause. What is harder for us to wrap our minds around is that sudden changes can result from a combination of factors of through a process scientists call percolation.

A percolation occurs when a small change to system inputs results in sudden and dramatic change in its outputs. The most common and easiest-to-understand application of percolation theory describes the flow of fluids through a semi-porous media, such as water through a bed of coffee grounds or natural gas through an underground rock formation. If the void volume of the media is lower than the percolation threshold, then the flow of the liquid is zero since it can’t make it through. As the void volume increases, the flow is still zero until the percolation threshold is reached, at which point there is a sudden change in behavior of the system, and the fluid now flows through. Percolations also occur as the result of a combination of variables rather than the single-variable example of void volume I used here.

In a multi-variable system, the inputs can undergo significant change with no observable change in output. This may lead the observer to believe that these inputs do not have an effect on outputs. Then a critical point, the percolation threshold(3), is reached and things suddenly change.

Let’s apply percolation theory to bee hive survival. The input variables are all of the stresses I listed above, and the output we are monitoring is hive loss over the winter. Consider that the transport of bees across the country by truck has been ongoing for decades with no change in hive loss. This can naturally lead to the conclusion that it has no negative impact on bees, so the practice continues to grow. The same phenomena with the other inputs such as monoculture farming expand, and again everything seems fine. Then a percolation threshold is reached involving a combination of these variables, and the rate of hive loss jumps up dramatically.

To my point of view, beekeeping in the U.S. crossed a complex percolation threshold in 2007. Since the root cause of the problem is complex and multi-variable, the response to the problem must be as well. I will discuss what I think can and should be done, as well as what I believe the local response should be, next week.

Have a comment or question? Use the interface below, or send me an email to commonscience@chapelboro.com.

(1) If you know what to look for, these two percentages should tell you that something has gone quite wrong. How can it be that 90% of the plants with which we co-evolved require pollination, but only 30% of our food calories come from pollinated plants? In part, this is because humans are omnivores rather then vegetarians. But it is also an outcome of the Western diet which relies on eating seeds such as corn and wheat, rather than leaves and fruits. We would all be better off if we ate more leaves and fruits, and would also be even more dependent on pollinators for our food supply.

(2) Of the stresses on bees, this factor does not receive much attention. The honey bees used in most of the developed world are the same species, and the queens are bred in only a few places and selected for docility. This sort of breeding reduces gene pool diversity over time and reduces the robustness of the species. This includes the bees I am buying this weekend. I discuss my internal conflict over this next week.

(3) Whenever I think about percolation theory (yes, I am nerdy enough that I do think about things like this), I always think about the game Blokus. In the beginning, putting your pieces on the board is easy, simple, and free flowing. You feel like this is a silly game which could be played by four year olds. Then all of a sudden, there is no where left to go; the board has percolated.

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