Are Pesticides Pushing Honeybee Die-offs Past the Tipping Point
17 Jan, 2012
Anyone who’s been stung by a bee knows they can inflict an outsized pain for such tiny insects. It makes a strange kind of sense, then, that their demise would create an outsized problem for the food system by placing the more than 70 crops they pollinate — from almonds to apples to blueberries — in peril.
Although news about Colony Collapse Disorder (CCD) has died down, commercial beekeepers have seen average population losses of about 30 percent each year since 2006, said Paul Towers, of the Pesticide Action Network. Towers was one of the organizers of a conference that brought together beekeepers and environmental groups this week to tackle the challenges facing the beekeeping industry and the agricultural economy by proxy.
“We are inching our way toward a critical tipping point,” said Steve Ellis, secretary of the National Honey Bee Advisory Board (NHBAB) and a beekeeper for 35 years. Last year he had so many abnormal bee die-offs that he’ll qualify for disaster relief from the U.S. Department of Agriculture (USDA).
In addition to continued reports of CCD — a still somewhat mysterious phenomenon in which entire bee colonies literally disappear, alien-abduction style, leaving not even their dead bodies behind — bee populations are suffering poor health in general, and experiencing shorter life spans and diminished vitality. And while parasites, pathogens, and habitat loss can deal blows to bee health, research increasingly points to pesticides as the primary culprit.
“In the industry we believe pesticides play an important role in what’s going on,” said Dave Hackenberg, co-chair of the NHBAB and a beekeeper in Pennsylvania.
Of particular concern is a group of pesticides, chemically similar to nicotine, called neonicotinoids (neonics for short), and one in particular called clothianidin. Instead of being sprayed, neonics are used to treat seeds, so that they’re absorbed by the plant’s vascular system, and then end up attacking the central nervous systems of bees that come to collect pollen. Virtually all of today’s genetically engineered Bt corn is treated with neonics.
The chemical industry alleges that bees don’t like to collect corn pollen, but new research shows that not only do bees indeed forage in corn, but they also have multiple other routes of exposure to neonics.
The Purdue University study, published in the journal PLoS ONE, found high levels of clothianidin in planter exhaust spewed during the spring sowing of treated maize seed. It also found neonics in the soil of unplanted fields nearby those planted with Bt corn, on dandelions growing near those fields, in dead bees found near hive entrances, and in pollen stored in the hives.
Evidence already pointed to the presence of neonic-contaminated pollen as a factor in CCD. As Hackenberg explained, “The insects start taking [the pesticide] home, and it contaminates everywhere the insect came from.” These new revelations about the pervasiveness of neonics in bees’ habitats only strengthen the case against using the insecticides.