Bee Decline Not Yet Felt in Agriculture

Nov. 10, 2008 -- A decline in bees and other insect populations is yet to impact on global crop yields, according to an international study.

But in the latest edition of Current Biology, researchers warn an increasing reliance on crops that need pollination could lead to future problems.

Co-author Saul Cunningham, of CSIRO Entomology, said the research was prompted by increasingly alarmist views about food availability in the face of declines in insect pollinator populations.

Research into the reliance on bee pollination for global crop production, estimates about one in three mouthfuls of food comes from insect-pollinated crops.

Cunningham said the loss of bees and other insect pollinators is due, among other things, to a combination of disease, reduction in native vegetation and use of insecticides.

In particular managed honeybees, which are used by farmers to pollinate large tracts of monocrops, have been decimated by disease in the form of the varroa mite and colony collapse disorder.

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During the 2006-07 northern hemisphere winter, a quarter of U.S. beekeepers lost more than half of their hives.

Cunningham said the research team, which included scientists in Australia, Argentina, Germany and the United States, looked at global crop yields during the past 45 years to determine whether the loss of pollinators was affecting the global food supply.

They rated crops on how much they depended on pollinators for maximum production.

This ranged from zero for crops such as wheat that are pollinated by the wind to 100 percent for crops such as almond trees that will not produce nuts without pollination.

He said they were surprised to find crop yields in the 45-year period had grown consistently by about 1.5 percent a year due to improvements in agriculture.