The global food crisis has prompted experts to point the finger at everything from stressed farmland to high oil prices to the impact of futures markets.
Now a United Nations report has raised another red flag for the future of food production: the plight of honeybees.
Bees are integral to agriculture: Of the roughly 100 crop species that provide 90 per cent of food worldwide, the UN food agency estimates 71 are pollinated by bees.
The report warns that a collapse of honeybee colonies would be devastating for fruit and vegetable production, and can be avoided by improving habitat protection and reducing pesticides.
In vast pockets of the world, their numbers are already in decline. A serious problem in Europe and the United States for decades, sudden bee colony losses are now surfacing in China, Japan and along the Egyptian Nile in Africa.
Scientists from around the globe have worked to unravel the mystery behind disappearing bees. The UN report, released Thursday, examines the latest science on collapsing bee colonies and points to about a dozen likely factors, from agriculture's increasing reliance on pesticides to air pollution and migrating parasites.
Yet the study also paints a hopeful picture for one of nature's most formidable pollinators. If certain agricultural practices and public policies are changed, says Marie-Pierre Chauzat, one of the report's lead researchers, a full-scale bee crisis can be averted.
"The warning at the moment is that we are maybe at a threshold. We have lights at the moment saying, 'Be careful,' " says Dr. Chauzat, a scientist with the French Agency for Environmental and Occupational Health Safety.
"The magic with nature is that it's reversible."
Concern about declining honeybee colonies is most prevalent in Europe, dating to the mid-1960s. The problem landed in North America about three decades ago. Today, the continent has its lowest number of commercial bees in 50 years.
In the United States, for example, the report cites expert estimates that honeybee colony losses during 2007-2008 were 36 per cent, much higher than the 10 to 20 per cent considered normal.
In Canada, bee hives are down four per cent, to roughly 575,000 from 600,000 two years ago, says Rod Scarlett, executive director of the Canadian Honey Council. But the insect's outlook has improved from a few years ago, when sudden bee deaths puzzled honey producers in several regions of the country, including Vancouver Island, Alberta and Ontario.
One of the main threats to commercial bees in Canada is the Varroa destructor, a parasitic mite that feeds on bee fluids and has spread nearly worldwide from its origins in southeast Asia.
Ernesto Guzman, an entomological researcher at the University of Guelph, believes more research is needed on controlling the mite - one of the main factors in bee-colony demise cited in the UN report.
"With better management and better mite control, the number of honeybee colonies that die could be reduced significantly," Dr. Guzman says.
Though their numbers are down in Europe and North America, the global stock of honeybees has in fact increased nearly 50 per cent in the past half-century, as pollination-dependant agricultural production has risen fourfold.
Dr. Chauzat suggests there are ways to boost numbers in hard-hit countries. For example, farmers could be given incentives to leave sections of land unplowed for several years, creating an enticing breeding ground for bees and other insects.