Bee Disappearance Has Baffled Experts
For several years, honeybee colony collapse disorder (CCD) — a mysterious malady that destroys honeybee hives, causing worker bees to abandon their home and die alone — has alarmed beekeepers and farmers and baffled scientists.
Since 2006, up to 40 percent of the bee colonies in the United States have succumbed to the disorder. Last winter alone, more than one-third of domesticated honeybees kept by beekeepers died.
As key pollinators, honeybees are an integral part of their ecosystem. More than one third of food crops in the United States depend on honeybee pollination for successful production, so a threat to bees is also a serious threat to the human food supply.
Viruses, fungi, parasites, pesticides, and even mobile phone signals have all been tested by scientists in the search for the culprit behind CCD. But until recently, no studies seemed to point to a single definitive cause.
Military and Civilian Partnership Leads Scientists to Possible CCD Cause
As it turns out, there may well not be a single cause of CCD. A study published this week in the journal of the Public Library of Science points to two pathogens, working in concert: a bee virus called invertebrate iridescent virus, or IIV, and a fungus called Nosema.
U.S. military microbiologists who specialize in protein analysis teamed up with civilian entymologists who specialize in the study of bees to uncover the connection. (Check The New York Times for the interesting story of how this military-civilian partnership was formed.)
By carefully analyzing the remains of dead bees from CCD-affected hives, the scientists were able to identify several different types of viruses, mites and fungi infecting affected bees. And they discovered that in nearly every CCD-affected hive, both the IIV virus and the Nosema fungus were present.
By itself, neither pathogen seems to cause full-blown CCD, but according to this study, in combination, the two illnesses are nearly always present together in hives destroyed by CCD.
More Research Still Needed to Find a CCD Cure
Despite the promising results from this CCD study, several issues surrounding CCD remain unclear. The study’s scientists are not certain whether the virus makes the bees more susceptible to fungal attacks, or vice versa. And it is not known why bees have become so much more affected by these illnesses over the past several years.
Could there be another environmental factor making the bees’ immune systems less capable of fighting off disease? One of the study scientists, Jerry Bromenshenk of the University of Montana, has taken care not to rule out that possibility, saying, “We truly don’t know if these two pathogens cause CCD or whether the colonies with CCD are more likely to succumb to these two pathogens.”
How You Can Help Honeybees Right Now
While the scientific world waits for further research on how to prevent honeybee colony collapse disorder, there are a few common-sense things that you can do right now to help support struggling honeybee populations.
Loss of plant biodiversity has caused bees to rely on a less varied, less nutritious diet. Concerned gardeners can help by growing plants that provide food for bees, such as hyssop, asters, and lemon balm.
Honeybees are also highly susceptible to the same pesticides that are often used by homeowners to kill carpenter bees and wasps. If you want to protect honeybees from pesticide stress, check labels carefully and avoid the use of pesticides that harm bees whenever possible — try to find alternative, organic ways of dealing with insect pests.
Image: Detail of honeybee photo from USDA. Public domain.