Photo: Megachile fidelis on Mexican sunflower. Credit: Kathy Keatley Garvey
The specter of election season is upon us and once again, the phrase “addiction to foreign oil” seems to be a particularly popular bludgeon among political rivals. As a nation, we are as fond of our addictions as we are of scrutinizing them. In the spirit of self-flagellation, let us add another to the list: addiction to foreign pollinators.
The European honeybee (Apis mellifera) is one of the most intensively managed introduced species in the world. Before high fructose corn syrup, honey was one of the few sweeteners available for human consumption. Early honey hunters scaled trees and endured countless stings to collect the elusive amber substance. In the 1600s, European colonists transported their tiny insect cargo around the world, from the shores of Tasmania to the North American colonies. In a few short centuries, the honeybee has spread to every continent except Antarctica.
Despite its cosmopolitan nature, the honeybee is not the hardiest of creatures. Colony counts have been declining for decades in the face of an onslaught of human-caused threats, including the introduction of an invasive endoparasitic mite, exposure to lethal viruses, and widespread pesticide use in industrial agriculture. In recent years, these threats have had very real consequences; between 1947 and 2005, biologists estimate that the number of honeybee colonies declined by 59%.
The outlook for honeybees was already looking grim, but few could have predicted the mysterious Honeybee Armageddon of 2006. In a single year, a previously undocumented phenomenon now dubbed Colony Collapse Disorder (CCD) resulted in the loss of hundreds of thousands of colonies worldwide.
Since then, bee biologists have borne a remarkable resemblance to their study organisms, busily trying to identify what has caused the deaths of billions of honeybees. A break in the case occurred this spring, when Chensheng Lu and colleagues at Harvard University identified a direct link between CCD and the use of neonicotinoid insecticides. Unlike other pesticides that kill insects nearly instantaneously, neonicotinoids persist in plant tissues long after spraying, presenting a risk to honeybees that consume plant pollen.
Despite the targeted efforts of beekeepers worldwide, honeybees appear to be in terminal decline. Given that this species is responsible for the pollination of 75% of our crops, this presents a serious problem for global food security. Native pollinator species, while historically viewed as inefficient and unreliable, are moving into the spotlight as a potential alternative to the honeybee. Last year, researchers at UC Berkeley reported that native pollinators in California already contribute at least 1 billion to the agricultural economy and pollinate 35-39% of California’s crops.
Though much of native pollinator conservation is tied to agricultural production, for some plant species, pollinator survival is quite literally a matter of life and death. “Some flowering plants have evolved to depend on a particular species of native bee for pollination,” says UC Davis bee biologist Katharina Ullmann. “It’s assumed that in these cases, if the bee species disappears the plant will disappear too.”
Organizations such as the Xerces Society are working to encourage the conservation of native pollinators and their habitats. Unlike many threatened mammalian species, pollinating insects can exploit tiny habitat patches, even rooftop gardens buried in the concrete jungle of Los Angeles.
In the face of plummeting honeybee colony counts and ominous predictions about the fate of US agriculture, it can be hard to look on the bright side. Even so, increasing appreciation for native pollinators has proven to be an unexpected silver lining. The saga of the honeybee is far from over, but a new age has already begun.
For more on native pollinators, visit Chris Bowman’s companion column Saving Bees in a Post-wild California.