Q. What is Colony Collapse Disorder?

Bee colonies are attacked by a variety of pathogens and parasites.

One major pathogen is the acute bee paralysis virus (IAPV), which causes a breakdown of the ribosomes in infected bees. The infected bees become paralysed and die when outside the hive.

Two major parasites are:

• the varroa mite (Varroa destructor), which feeds on the blood of bees, wounding the bee and weakening its immune system. Varroa mites are also vectors for viruses such as IAPV.

• the fungus (Nosema ceramae), which infects the intestinal tract of bees, reducing the bee's ability to process food, and makes the bee susceptible to infection and chemical attack.

During the colder winter months in the USA, on average about 15 - 25% of bee colonies die. However, in late 2006 American beekeepers began reporting much higher losses of colonies (up to 90% in extreme cases), and in the four years since then, more than a third of bee colonies (approximately three million) have failed to survive the winter in the USA. Similar losses have been reported in Canada and Europe, resulting in the loss of billions of honey bees.

This phenomenon has been termed Colony Collapse Disorder (CCD) and to date no cause has been identified. The main symptoms of CCD are a bee hive that has a live queen in residence with very few or no adult bees; no dead bees are present in the hive. Honey is often present in the hive along with immature bees. As there are no workers to care for these young bees, the colony soon dies.Scientists are investigating the possible causes of CCD; it is unlikely that it is caused by a single factor.