Beeware

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Walking on the Leslie Street spit in Toronto, I was thrilled to see this golden rod plant covered with bees. The world's apian population is shrinking--more than fifty per cent of European honey bees have died--yet, we rely on them to pollinate seventy per cent of our crops. And, we don't just leave it up to wild bees buzzing around in random patterns, accidentally transferring pollen from one plant to another. Nearly all fruit and vegetable crops need insects to pollinate them, and farmers "rent" hives of bees to do the work at various times of the year. Artificial pollination is possible, but not on the industrial scale needed for the world's food supply.

So, what is decimating the bees? In 2000, Australian scientist Dr Dennis Anderson discovered the Varroa desructor mite. This parasite attaches itself to a bee and sucks its blood, transmitting viruses and bacteria with fatal consequences. The mites travel from bee to bee , relying on their sense of smell. Originally infecting only Asian honey bees, Varroa mites jumped species in the 1970s when European honey bees were introduced to Asia because of their superior pollinating ability. Once the mites got used to the new species' scent, they infected them as well. Europe's feral bee population is now extinct, and hived colonies are at risk as well. In North America, the number of hived colonies has fallen by fifty per cent from five million to 2.5 million since 1988.

The bad news is that Varroa mites are very good at developing resistance to chemicals designed to eradicate them. The (possibly) good news is that researchers believe they can breed a honey bee that will be resistant to the mites, although genetic modification has its own problems. However, Varroa mites are not the only threat to the world's honey bee population. Pesticides sprayed on crops can affect the pollinating bees as well, and one chemical company, Bayer, has a complex relationship to bee health. On the one hand, Bayer scientists have developed a plastic "gate", coated in a substance fatal to Varroa mites, which, when installed at the entrance to a hive, prevents infection. On the other hand, however, Bayer manufactures neonicotinoid pesticides which also threaten bees. More than thirty Ontario beekeepers are currently suing Bayer and another company, Syngenta, for $400 million in damages for the death of their bees, allegedly by the neurotoxins in these pesticides.

Furthermore, the world's bee population is threatened by a syndrome called "Colony Collapse Disorder" (CCD), in which all the worker bees in a hive suddenly disappear, leaving the queen unattended. This phenomenon is not new: it has been documented in Europe and North America since at least the nineteenth century, but we still do not know exactly what causes it. Now, it is seen on every continent and it has reached dangerous proportions.

Researchers have hypothesized a number of reasons for CCD, including pesticides used on corn crops which might interfere with the bees' homing ability, Varroa mites affecting the bees' immune systems, climate change, and the development of industrial apiculture. Large-scale bee breeding may have interfered with bees' natural genetic diversity, weakening colonies, and the practice of transporting hives over long distances for agricultural pollination might also play a part. So far, there have been no firm conclusions but CCD is being studied all over the world.

Fortunately for North American agriculture, honey bees are not native to this continent, so many crops can be pollinated by other insects. The honey bees, however, are the most efficient pollinators and farmers have come to rely on them.

Writing more than one hundred years ago, Charles Darwin realised how much plants rely on the insect he called the "humble bee," and the intervening years have only made that dependence stronger.

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