Collapse of the Colonies
Can Vermont’s Bees Remain Strong and Independent?
Written onMarch 01 , 2008
“One of every three mouthfuls of food we eat, and of the beverages we drink, are delivered to us roundabout by a volant bestiary of pollinators.”
- Edward O. Wilson, Harvard University
The word “localvore” may have been Oxford American Dictionary’s word of the year for 2007, but a close runner-up was “colony collapse disorder,” an unexplained phenomenon in which bees disappear mysteriously from their hives. The two words are more related than one might think, though. Given the risk this disorder poses to the foods we eat in Vermont, it’s important to ask: how serious is colony collapse disorder in our state?
It’s easy to ignore the myriad organisms on which we depend. Most are small, unnoticeable creatures that we simply label as pests. But as we support local farmers and seek to sustain ourselves from our own gardens, we must remember that our endeavors would not be possible without pollinators–the multitude of seemingly tireless workers who transfer pollen from anther to stigma, all for the simple reward of a drop of nectar.
Pollination is the essential reproductive strategy of the world’s more than 240,000 flowering plants–at least three quarters rely on an animal to conduct the necessary transfer of pollen. The best known pollinator is the honey bee (Apis melifera), which effectively pollinates more than 100 commercially-grown crops in North America. It is the supreme pollinator, living in colonies of thousands of workers, pollinating acres of plants, and providing honey for human consumption. But the honey bee is not alone, and is not even native to this continent. For the millennia prior to the bee’s introduction, pollination was performed by a multitude of native insects, including solitary bees, wasps, flies, beetles, moths, butterflies, and thrips, as well as birds and a few mammals.
Honey bees were first introduced to North America at the Virginia colony in the early 1600’s, and from there, beekeeping slowly spread north into New England, arriving in Vermont around 1720. At first, bees were kept in makeshift hives and allowed to gather and hoard their honey supply. In the fall, keepers would simply kill the bees with a sulfur gas and destroy the hive to collect the honey, hoping they could restock in the spring by finding wild swarms.
In 1862, modern apiculture was born when L.L. Langstroth developed the movable-frame, top-bar hive. This invention permitted access to the hive’s interior so that honey could be collected without destroying the occupants. Beekeeping flourished, and by 1900, Vermont and Maine led New England in honey production.
In 1947, the U.S. Department of Agriculture estimated there were 5.9 million colonies in the United States, but by 2005 that number had dropped to 2.4 million. Much of the decline has been attributed to the Varroa mite, a tiny parasite that lays its eggs in comb cells so its young can feed on the developing bee larvae. Apiculturists warn that once a hive is infected with this mite, it is destined to fail within one or two years.
Colony Collapse Disorder (CCD) gained media coverage in 2006, when some large beekeeping operations in the U.S. reported losses as high as 80% of their hives. Many causes have been suggested for CCD, including electro-magnetic radiation associated with cell phones (a theory now discounted), genetically-modified crops, malnutrition, and use of synthetic pesticides. Compounding these issues is the practice of moving colonies long distances to service crop monocultures during peak flowering periods. Notable are the large numbers needed to pollinate the California almond crop during a short period in the spring, when colonies are imported from as far away as Australia and Canada. More than half of the 2.4 million colonies in the U.S. are needed for this single crop, and the co-mingling of millions of bees, along with their parasites and diseases, increases the potential for spreading pathogens around the continent.
Experts are now saying that CCD is more likely caused by a combination of factors that stress and weaken a colony to the point of collapse. Among these stressors are malnutrition, long-distance transport of hives, Varroa mites, viral infections, other diseases (such as American Foul Brood), and the use of chemicals to control these pathogens. Ross Conrad of Dancing Bee Gardens in Middlebury observes that the answer to CCD is simply to reduce stress on the bees. “Just like people, if you burn the candle at both ends, or eat poorly on a consistent basis, you will be much more likely to come down with a cold.”
In the midst of all this bad news is something encouraging. According to Steve Parise, the Vermont State Apiculturist, CCD has not yet been reported in Vermont. “The decline of honey bees,” he reports, “has not been as evident here, and the number of beekeepers [about 1,600] and annual production of honey [500,000 pounds] has remained fairly constant the past few years.” This brighter picture may be testament to the good hive husbandry practiced by many of Vermont’s beekeepers, the majority of whom keep fewer than five hives. Also, many have adopted an organic approach that, in Ross Conrad’s view, “reduces stress on the bees, and is why organic beekeepers seem to be faring better during these times of such devastating losses elsewhere.”
Still, Vermont’s beekeepers must remain diligent in protecting themselves from losses caused by Varroa mites. According to the 2007 report of the Vermont apiculturist, 93% of inspected hives were infected by this parasite, and some keepers are losing as much as one third of their colonies each year. Although these numbers seem high, many keepers are breeding their own replacement stock with bees resistant to mite and viral problems. Michael Palmer, president of the Vermont Beekeepers Association, predicts a brighter future as more of the state’s beekeepers conduct on-site breeding and build resistance into their colonies.
Although honey bees are faring relatively well in Vermont, there is growing concern about some wild pollinators. There are 49 species of bumble bees in the United States (18 in Vermont), and some have become commercially important because they function as “buzz-pollinators”–a bee that literally vibrates pollen grains from the anthers of certain flowers, including cranberry, blueberry, tomato, and cucumber. As an alternative to honey bees (which do not buzz-pollinate), several bumble bees are imported and managed for crop production, most notably greenhouse-cultivated tomatoes. However, imported bumble bees often escape to the wild, where they can potentially infect native populations with pathogens that arise in confined colonies. As a result, several species of native bumble bees have suffered significant declines.
In 2007, the National Academy of Sciences published the Status of Pollinators in North America report, warning that “pollinator decline is one form of global change that has a credible potential to alter the shape and structure of the terrestrial world.” Landowners throughout Vermont can help improve habitat for native pollinators by doing three basic things.
First, provide a diversity and abundance of pollen and nectar sources by planting flowers that bloom at different times during the growing season. For bumble bees, the most critical period is early spring, when freshly-emerged queens (the only members of the previous year’s colony to survive the winter) need substantial amounts of food to establish new colonies. Native or naturalized plants are considered best, since they have adapted to local growing conditions and native pollinators have evolved along with them.
Second, provide quality nesting sites. Because many native bees nest in soil, this can be done by simply providing patches of bare ground adjacent to crop fields and gardens. For some species, including mason bees and bumble bees, homemade nest boxes can be set out. Guidelines for constructing nest boxes (and selecting beneficial plants) are available from the Xerces Society for Invertebrate Conservation, www.xerces.org.
Third, cut back or eliminate the use of pesticides on your land. This will reduce the chance of inadvertently killing beneficial insects and/or plants. If chemicals are deemed necessary, choose ones that directly target specific weeds or pests, and make sure your application methods reduce drift into natural habitats and are used at night, when bees are inactive. The Natural Resource Conservation Service, www.nrcs.usda.gov, offers guidance on how to improve pollinator habitat through such actions as the creation of hedgerows and wildflower meadows.
Homeowners can also learn to tolerate weeds along property edges and allow old fields to repopulate with weeds and wildflowers. Simple measures such as these will help perpetuate healthy populations of beneficial insects and ensure that the pollination services they perform in Vermont will continue to enhance our local food production for years to come.
Photo by Anicet Desrochers