January 11, 2011
By: Nick Engelfried
A sharp decline in the populations of several bee species threatens to affect the health of important US food crops by depriving them of the pollination service bees provide. Since 2005 bees in the US have been declining due to a once-mysterious illness known as colony collapse disorder. Not all the news is grim however: recent scientific studies suggest banning the use of certain pesticides could help bees recover and go on pollinating crops for years to come. In response to these findings, environmentalists have launched a campaign pressuring the Environmental Protection Agency (EPA) to ban chemicals linked to bee die-offs.
US bee keepers and researchers first began noticing large-scale honey bee die-offs in the in 2005, and the name “colony collapse disorder” was coined soon afterwards. For years scientists were unable to pin down the cause of the die-offs, though parasites and chemical pesticides were regarded as the most likely suspects. Meanwhile the severity of the problem has continued to grow: there is now evidence that colony collapse disorder or a similar malady is affecting not only honey bees, but at least four bumble bee species that are also important plant pollinators. Today researchers suspect bee declines are caused by a combination of factors, including parasites and habitat loss. But the most important contributor of all may be a group of pesticides known as neonicotinoids.
Based on the chemical nicotine, neonicotinoids were first applied to crop fields in the United States in the late 1990s, and since that time their use has increased steadily. In 2003 the German-based company Bayer applied to the EPA for permission to sell a neonicotinoid called clothianidin on the US market. Now used on corn, sugar beets, canola, wheat, and other crops, clothianidin interferes with the nervous systems of insects and is meant to kill insect pests. However deadly compounds from the pesticide also end up in the nectar and pollen of crops, where they affect bees and other pollinators that come to the flowers to feed.
Unbeknownst to the public in 2003, EPA scientists expressed concern that clothianidin could seriously harm the honey bees that pollinate important crops. However the EPA granted “conditional approval” for Bayer to sell the pesticide anyway, allowing its application on vast stretches of US farmland. Since then Bayer has conducted studies it says show the pesticide has no significant effect on bee populations.
But independent researchers, like entomologist James Frazier of Pennsylvania State University, say the studies were flawed. According to Frazier, Bayer attempted to compare the health of bee colonies exposed to clothianidin with those not exposed to the chemical. But Bayer’s methodology failed to ensure the bee populations were kept separate, invalidating the conclusions drawn from the study.
Finally in December of 2010, leaked emails and other documents highlighted instances where the EPA ignored the advice of its own scientists so Bayer would be allowed to sell clothianidin in the United States. During the same time period other countries where bees have declined have been banning use of the chemical. France, Slovenia, Italy, and Germany—the country where Bayer is based—have all outlawed the use of clothianidin. Since banning the pesticide these countries have seen dramatic improvements in their bee populations. Environmental organizations like the Pesticide Action Network are now calling on the EPA to ban clothianidin in the United States. The online activism group Avaaz.org has launched a petition asking EPA Administrator Lisa Jackson to end the use of the chemical.
Losing the most important pollinator bees in the US would affect not only crops grown for food, but natural ecosystems from woodlands to alpine meadows. Particularly worrying from the standpoint of native plant and animal life is the fact that bumble bees as well as honey bees are showing signs of decline. Populations of four bumble bee species studied by researchers have already declined by 96% leading to fears that these species could disappear completely. Part of the importance of bumble bees is they remain active at lower temperatures than most other insect pollinators, and emerge from hibernation to pollinate the first flowers of spring before other bees are out and about.
“Bees are dying off and our entire food chain is in peril,” says Avaaz.org. “If we urgently get the [US] government to join the ban [on clothianidin] we could save bees from extinction.”
Photo credit: Andy Hay