Friday, February 25, 2011

Where Have All The Bees Gone?

We ought to do good to others as simply as a horse runs, or a bee makes honey, or a vine bears grapes season after season without thinking of the grapes it has borne.
Marcus Aurelius

Bees work for man, and yet they never bruise Their Master's flower, but leave it having done, As fair as ever and as fit to use; So both the flower doth stay and honey run.
George Herbert, The Church: Providence

Better one bee than a host of flies.
Italian proverb

Hard at Work: This bee, Osmia ribifloris (on a barberry flower), is an effective pollinator of commercial blueberries (because it is blue) and is one of several relatives of the blue orchard bee, Osmia lignaria. Similar in appearance, the blue orchard bee is also a successful commercial pollinator that is now being evaluated for use in a wider range of crops.
Photo Credit: USDA Photo by Jack Dykinga, 2006.

Bees are amazing insects. And it's a wonder and a bit of nature's magic to see them buzz from flower to flower, carefully and assiduous doing their work. Unless you are allergic to them, as some people are, you could admire their qualities from fairly close up. Every summer, I await the bees, watching them fly from flower to flower in my modest garden populated with a few local flowers. They help humanity in numerous ways.

Chief among them are pollinating flowering plants and gathering nectar to produce honey. Of the two, pollination, the transfer of pollen from one flower to another, is critical to fruit and seed production. The distinction is valid and an important one, since different bee species focus on different tasks. Bees that gather nectar, honeybees, will pollinate flowers, but bees that deliberately gather pollen are more efficient at pollination.

About one-third of the human diet comes from insect-pollinated plants, and the honeybee is responsible for 80 percent of that pollination, says the U.S. Department of Agriculture (USDA).  Bees of various species can be found in every continent, except Antarctica.

There are almost 20,000 known species of bees, categorized into seven to nine recognized families. The honeybee belongs to the family called, Apidae, representing a small fraction of all bees. Currently, there are only seven recognized species of honeybee, and a total of 44 subspecies.

Some other types of related bees produce and store honey, but only members of the genus Apis are true honeybees. One of the most common species found in North America is Apis mellifera, the European honeybee. It was introduced by English settlers to North America, when they arrived by ship in Virginia, in 1622.

Given its beginnings as an agricultural society, the honeybee was important for crop production. Honeybees continue to play an important role in food production, as insects that are considered pollinators. The list of crops that simply won’t grow without honey bees is a long one: apples, cucumbers, broccoli, onions, pumpkins, carrots, avocados, almonds, and dozens of others: a total of $15 billion worth of crops that depend on the honey bee in the U.S. alone.

But it's not feral, or wild honeybees, which are doing the work. From 1972 to 2006, there has been a dramatic reduction in the number of wild honeybees in the U.S. Wild honeybees are almost non-existent. Instead, there is a whole industry now where farmers, who used to rely on feral honeybees for pollination, must now rent managed colonies. That's right: bees for hire.

It's a commercial venture with commercial colonies. In the U.S., beekeepers as a group earn much more from renting their bees out for pollination than they do from honey production. One problem with that for bee survival rates is that when bees are trucked around, they intermingle with other bees from all over, which helps spread viruses and mites among colonies. It is also a strain on the colony.

Now, here's the problem. There are fewer bee hives in the U.S. today than at any time in the last 50 years—about 2.3 million colonies, or hives. An average colony has about 50,000 bees. Yet, there are not enough bees. For example, the $2 billion almond crop in California requires one million honeybee hives, or colonies, for cross-pollination, at about two colonies per acre. Depending on the crop, it can take between one and four colonies of honeybees per acre for pollination. (Apples require one, blueberries up to four.)

One of the current concerns regarding honeybees is what has been called colony collapse disorder, where worker bees from a beehive disappear and don't return. As of yet, there is no scientifically verifiable explanation.

The queen bee, in a sense, has lost her loyal subjects. They are not returning to the hive, or colony. An estimated one-third of the colonies in the U.S. have for yet unexplainable reasons vanished, triple the norm of 10 per cent. The rate is 20 per cent or higher in much of Europe, and similar rates have been reported in Latin America and Asia.

Starting the Honey-Making Process: A European honey bee (Apis mellifera) extracts nectar from an Aster flower using its proboscis. Tiny hairs covering the bee's body maintain a slight electrostatic charge, causing pollen from the flower's anthers to stick to the bee, allowing for pollination when the bee moves on to another flower.
Photo Credit: John Severns, 2007

Various Possible Explanations

Scientists are looking for possible explanations, including the United States Department of Agriculture, which says:
A perfect storm of existing stresses may have unexpectedly weakened colonies leading to collapse. Stress, in general, compromises the immune system of bees (and other social insects) and may disrupt their social system, making colonies more susceptible to disease.

These stresses could include high levels of infection by the varroa mite (a parasite that feeds on bee blood and transmits bee viruses); poor nutrition due to apiary overcrowding, pollination of crops with low nutritional value, or pollen or nectar scarcity; and exposure to limited or contaminated water supplies. Migratory stress brought about by increased needs for pollination might also be a contributing factor.
Other considered possibilities have been Israel acute paralysis virus, or IAPV, first discovered by Israeli scientists in 2002, which causes paralysis in bees that then die outside the hive; and Neonicotinoid pesticides, including clothianidin, which are neurotoxins used to protect crops against pests, yet these chemicals may also be harming honeybees.

Although nothing conclusive has been reported yet, neonicotinoid insecticides has been limited or banned in a number of countries including Germany, Italy, France and Slovenia. A lot of fingers have been pointing at neonicotinoid insecticides – relatively new compounds which mimic the insect-killing properties of nicotine. Both the U.S. and Britain however, continue to allow the use of neonicotinoids.

That might be one cause, but not the only one. In fact,there might be a  number of causes, depending on which region of the world the colony collapse is taking place, reports in a recent article:
It’s becoming clear that there is no single parasite, virus or chemical to blame, argues Frances Ratnieks, a bee scientist at University of Sussex in Brighton.

Instead, honeybees are probably dying for all kinds of different reasons from loss of their foraging grounds to increased exposure to global pathogens, Ratnieks wrote in a review of the issue in the journal Science.

“We may conclude that colonies are dying for different reasons in different parts of the world and I would say that if that is the case, I would not be the least bit surprised,” Ratnieks told
That is why some scientists say further study is required, the emphasis of a recent paper, Colony Collapse Disorder in Context, by Geoffrey R. Williams et al of Dalhousie University's department of biology in Halifax, Nova Scotia. In it, the paper's authors said: "The point is, honey bees die from many things. We must be careful to not synonymize CCD with all honey bee losses."  It's a tricky problem, no doubt.

The consequences of continuing reduction in bee colonies are far-reaching: a collapse in our food chain and higher food prices. Let's hope that scientists and researchers looking into this problem will come up with a solution soon. I will keep you posted.


Update: To find out more, I would recommend the excellent documentary, Vanishing of the Bees, directed by George Langworthy and Maryam Henein, and narrated by Ellen Page.