Analysis

Colony Collapse Disorder

What’s Happening?

In recent months, Colony Collapse Disorder (CCD) has become a major concern in North America. According to the Canadian Honey Council, CCD is present if the following conditions occur simultaneously:

  1. The complete absence of adult bees, with no accumulation of dead bees.
  2. The presence of capped brood in colonies.
  3. The presence of food stores not immediately stolen by other honeybees, or attacked by pests such as wax moths.

A recent New York Times article states that over a quarter of America’s 2.4 million colonies have been lost – totaling some tens of billions of bees (Barrionuevo). According to an MSNBC report, 27 states, including California, have been affected, and similar occurrences have been reported in Brazil, Canada and Europe.

This is especially worrisome for the agricultural industry. The same MSNBC report cited earlier states that one-third of our diet comes from pollinated plants, and honeybees account for 80% of that pollination. But it might be too early to hit the panic button. Dr. Eric Mussen of UC Davis believes that California should still have enough bees to pollinate this year’s crops. However, this supposes that further collapses do not occur.

Similar Occurrences

This is not the first time CCD has appeared. Dr. Eric Mussen cites a one-year CCD occurrence in 1975, and a three-year occurrence from 1963-65. It was a situation similar to CCD that prompted the Higes study that discovered N. ceranae in Spain.

What’s causing it?

Scientists throughout the world are trying to find out what’s behind the latest CCD.

In April 2007, the San Francisco Chronicle reported that UCSF biochemist Dr. Joe DeRisi had discovered N. ceranae in dead bees from Merced County, California. The Spain study had already shown that N. ceranae could wipe out a colony.

Nosema might not be the only cause though. Some scientists still suspect varroa mites, especially in Hawaii, are responsible.

Dr. Mussen cites other issues that could be behind the reduced populations. Honey crops were down last year, and many bees didn’t access adequate forage. In addition, bees have been exposed to toxins, such as insecticides, and been subjected to 3,000 mile cross-country trips to be used in almond pollinations. He agrees with Dr. DeRisi that N. ceranae has reached the States, but also notes that it isn’t present in every collapsed colony.

The Future of Honeybees

Colony Collapse Disorder is a great concern for the future of honeybees and the agricultural industries that depend on their pollination services. Unfortunately, nothing can be done to prevent or control CCD until a definitive cause is discovered. Once a diagnosis is reached, there is no certainty that an effective treatment will exist. If nosema is responsible, then effective antibiotic treatments exist, but if mites are the culprits, the treatment options are far less effective. If environmental causes are found, then treatment will have to involve widespread and difficult changes in the management of bee colonies (such as not moving bees cross-country) and in agricultural practices in general (such as reducing the use of insecticides).

In general, honeybees face a precarious future. Infestations by mites, protozoan parasites, and pests, as well as a variety of diseases caused by viral, bacterial, fungal, or environmental agents have caused (and continue to cause) much devastation for honeybee colonies. The demand for pollination services continues to grow, while colonies continue to face increased threats and losses. More ways to effectively treat and control honeybee diseases must be found. Potential substitutes for commercial pollination are also needed. Honeybees are an essential component of agricultural production worldwide, and their loss would be extremely damaging. While it is unlikely that any drastic changes will occur in the near future, this is a topic that should be of concern to everyone.



© 2007 The Board of Trustees of the Leland Stanford Junior University. All rights reserved.