Colony Collapse Disorder is the single biggest threat currently faced by honeybees. Beekeepers first started to report the sudden disappearance of bees from their hives in 2006 in the Eastern United States. Over the last 3 years, CCD has killed over one in three bee colonies in 35 states across the US. In some cases, up to 90% of bees have been lost, and the problem is now worldwide – there have been losses reported in both Europe and Asia.
So, what are the symptoms and causes of colony collapse disorder? The main symptom of CCD is simply no or a low number of adult honey bees present but with a live queen and no dead honey bees in the hive. Often there is still honey in the hive, and immature bees (brood) are present.
Symptoms of Colony Collapse Disorder
- An almost overnight disappearance of virtually all the worker bees – within a few days, previously thriving well established colonies lose almost all of its adult bees. Unlike other diseases or infestations, there are no dead bees to be found. They simply leave the hive and never come back.
- The queen and a small number of very young bees, just hatched, remain and these tend the queen. You know they are young as they are light colored and still fuzzy.
- Lots of honey and pollen still in the hive, and also a lot of brood left behind.
Normally when a colony dies or is abandoned, scavengers (like ants, small hive beetles, and wax moths) very quickly come in and steal the honey, dead bees, or pollen that has been left behind. But with CCD, the anecdotal evidence is that this does not seem to happen. Other creatures stay away from the hive. No-one knows why, but it does suggest that they somehow instinctively sense that it is contaminated and so stay clear.
Causes of Colony Collapse Disorder
Causes are largely still unknown, but there are several main suspects. There is one theory that cell phone masts may be scrambling bees’ navigational systems. While this has not been completely ruled out, recent research has failed to find any evidence of a link. Most experts believe the cause of colony collapse disorder is more likely to be related to parasites (particularly Varroa and Tracheal mites), disease (especially Nosema) or pesticides.
Each individual beekeeping parasite and disease, while often damaging, is not thought to be sufficient to cause colony collapse disorder. In colonies affected by CCD, scientists found some evidence of infestation or infection, but no more so than in colonies without CCD.
More attention is now turning to chemicals. An analysis by Penn State researchers of beehive wax has shown very high levels of pesticides used by beekeepers in the hives to combat Varroa mites – particularly fluvalinate and coumapho.
The researchers also found lower levels of 70 other pesticides, not used by beekeepers but by farmers on agricultural crops. These were also present in pollen and in the bees themselves.
And particularly worrying is the interaction between these different chemicals. For example, initial research has found that some combinations of fungicides and insecticides can be a 100 times more toxic than any of the chemicals individually.
Whether these pesticides are a contributory factor to CCD is still unclear, but they are definitely stressors. One theory is that the combination of pesticides with the other existing stressors (parasites and disease) together cause the perfect storm, and hence colony collapse disorder.
Whatever the cause, CCD is a serious threat both to bees and to our food supply. The one positive is the increased public awareness of the crucial role that bees play. Hobby beekeeping has never been so popular, which can only be good – the more people who start beekeeping, the better the chance of survival for the honey bee.
So, yet another good reason to get out there, and start beekeeping.