GAUSE -- For the first time since Thanksgiving, commercial beekeeper Clint Walker III is working with his colonies of honeybees scattered across Central Texas ranchland.
By April 1, Walker hopes to triple the size of his hives that are currently pollinating yaupon holly trees several miles from the Brazos River. A few hundred yards from a herd of grazing cattle, Walker, who runs the honey business started by his father in 1938, is checking on the colonies' health and giving them nutrients to stimulate the queens to start laying eggs.Unlike those of most U.S. commercial beekeepers, Walker's hives are staying home this winter. For the second straight year, he won't be shipping bees to California for February's annual pollination of the almond crop."I've been chemical-free for nearly two years," Walker said. "We've stayed out of agricultural fields to cut out their exposure to chemicals, and my bees are finally starting to behave like bees again."It's a result of his experiences with colony collapse disorder, a malady that has hit U.S. beekeepers hard in recent years and caused his hives to plummet from a peak of 2,500 in 2006 to fewer than 1,000 today.While a variety of culprits have been identified as possible causes of colony collapse, including pesticides, varroa mites, viruses and a parasitic fly that turns them into so-called zombie bees, the search for a solution is crucial with bees pollinating about a third of the U.S. food supply.Since Walker changed his business practices to focus solely on honey making, new research about the risks of pesticides continues to come forward.This month, the Sierra Club called on the EPA to ban clothianidin, a seed treatment for corn, after scientists at Purdue University found that it affected bee health. The research showed that clothianidin, a neonicotinoid pesticide, is present in areas where bees pollinate long after the seed has been planted. Neonicotinoids target the central nervous system of insects."Despite numerous attempts by the beekeeping industry and conservation organizations to persuade the EPA to ban clothianidin, the EPA has failed to protect the food supply for the American people," said Laurel Hopwood, chairwoman of the Sierra Club's Genetic Engineering Action Team.Emerging researchWhile many headlines in recent years focused on chemicals that could kill bees, much of the new research is concentrating on lower levels of the pesticides that may be changing bees' behavior or weakening their immune system.These sublethal effects may play a role in explaining why many beekeepers like Walker struggled to rebuild their hives years after they were hit by colony collapse.Last week, a study published in the science journal Naturwissenschaften, documented the effects on bees given sublethal doses of the widely used pesticide imidacloprid. The study showed that the number of infections from a parasite, Nosema, increased significantly after exposure."Interactions between pesticides and pathogens could be a major contributor to increased mortality of honey bee colonies, including colony collapse disorder and other pollinator declines worldwide," wrote authors Jeffrey Pettis of the USDA-ARS Bee Research Lab; Dennis vanEngelsdorp and Galen Dively, both of the University of Maryland; and Josephine Johnson of the University of Maryland Baltimore.At the North American Beekeeping Conference this month in Las Vegas, Walker, whose term on the National Honeybee Advisory board ended in December, surveyed an audience of beekeepers to see whether they had seen their colonies being lethargic, not multiplying and not producing the normal amounts of honey. Almost all in the audience raised their hands."I call it colony malaise," Walker said. "It's a failure to thrive."Those beekeeper accounts shouldn't be taken lightly, said James Frazier, an entomology professor at Penn State University who is also studying the sublethal effects of pesticides."These guys understand the impacts pesticides are having; they just don't understand how, and it's up to the research community to figure out those answers for them," Frazier said last week.Multiple causesFrazier cautions that it is a mistake to focus on a single cause for colony collapse or related problems. Instead, researchers should take a more nuanced approach, he said."I think in the end, there could be a number of scenarios from two, to a dozen or up to 20 that give similar impacts, the worst of which would be the collapsing colony," Frazier said.There are an estimated 250,000 honeybee colonies in Texas, with each typically housing 40,000 to 60,000 bees.Nationally, beekeepers reported total losses from managed honeybee colonies of about 30 percent from all causes for the 2010-11 winter. Those totals were similar to losses from the previous four years. The latest annual survey conducted by the U.S. Agriculture Department and the Apiary Inspectors of America should come out this winter.Finding answers is important because bees add an estimated $15 billion in value each year to such staples as nuts, fruit and vegetables, many of which require bee pollination.Marion Ellis, a University of Nebraska-Lincoln professor of entomology, said more research is needed on sublethal doses as scientists work to give the EPA and other agencies new screening tools for pesticide use, including neonicotinoids and fungicides."Our work with sublethal effects is in its infancy," Ellis said. "I have a lot of good questions and need a couple of good years of research. I certainly don't have all of the answers."Bill Hanna, 817-390-7698Twitter: @fwhannaHave more to add? News tip? Tell us
