September 18, 2009
Apiculture Congress Tackles Mystery Of Dying Bees
Attendees of this year's Apimondia, the 41st world apiculture congress, in southern France are focusing on what is killing the world's bees.
Pesticides, viruses, industrialized farming and fungus are among the possible reasons why bee hives throughout parts of North America, Europe, and Asia have been struck by a mysterious ailment known as Colony Collapse Disorder (CCD). Although bee communities naturally lose around five percent of their numbers during normal times, up to 90 percent can be wiped out in CCD.
The CCD phenomenon is frightening for beekeepers, many of whom are small-scale operators or hobbyists without the clout and subsidy support that other agricultural sectors receive.
Food experts and environmental scientists are concerned as well, given that the Western honeybee is such a critical link in the food chain, fertilizing about 100 different types of crops.
Indeed, more than 30 percent of the food on our plates gets there thanks to Apis mellifera. Some estimate that this unseen, unsung pollination is worth more than $200 billion a year, with hives often transported to monoculture farms to work at specific times of the year.
Wild bees, bats and other pollinators are not ample enough to perform an equivalent amount of work, leaving significant implications for large-scale agricultural production if honeybees and beekeeping are wiped out.
"In China, fruit farmers in Sichuan are having to hand-pollinate their orchards," Henri Clement, president of the National Union of French Beekeepers, told the AFP news agency.
The underlying cause of CCD, which involves a complex web of factors, remains unclear despite extensive investigation.
Among the suspected culprits are a blood-sucking mite called varroa, a single-celled fungal parasite known as Nosema cerenae that causes bee dysentery, and pesticides used in fields that are pollinated by bees.
Some in Europe have suggested that an intruder known as the Asian hornet, or Vespa velutina, may be responsible. The insect lurks near beehives and captures the honeybee in flight and devours it.
Other possible explanations include poor nutrition caused by mega farms stripped of hedgerows and wild flowers, and spreading suburbs rife with concrete, roads and lawns. Both would deprive the bees of a proper diet.
But despite the theories, there is no consensus or single theory that explains why bee colonies are simultaneously collapsing in so many different parts of the world. Some say climate change may play a role.
Entomologists at the University of Illinois reported last month that bees in hives affected by CCD had high levels of damaged ribosomes "“ a critical protein-making system within the cells.
These ribosomes seemed to have been hijacked by picornia-like viruses, which took control of the cellular machinery to force it to produce only viral components.
Picorna-like viruses are carried by the varroa mite, which has proliferated by being unintentionally introduced through commercial transactions of bees.
"If your ribosome is compromised, then you can't respond to pesticides, you can't respond to fungal infections or bacteria or inadequate nutrition because the ribosome is central to the survival organism," researcher May Berenbaum told the AFP.
Meanwhile, researchers at University of Leeds in Britain have begun a three-year study to investigate whether the bees' decline might be due to a lack of variety in the sex life of queen bees.
The scientists are looking into whether a smaller number of potential mates would cause the bee colonies to become less genetically diverse, and therefore more prone to disease.
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