Since late 2006, honeybees in Europe and North America have been mysteriously disappearing. Once abuzz with activity, hives suddenly turned into honeycombed Marie Celestes. They still had plentiful supplies of honey, pollen and youngsters but the adult workers vanished with no traces of their bodies. The phenomenon has been dubbed colony collapse disorder (CCD). In the first winter when it struck, US hive populations crashed by 23% and in the next winter, they fell again by a further 36%.
Eager to avert the economic catastrophe that a bee-less world, scientists have been trying to find the cause behind the collapse. Amid wackier explanations like mobile phone radiation and GM crops, the leading theories include sensitivity to pesticides, attacks by the vampiric Varroa mite or a parasitic fungus called Nosema, infections by various viruses, or combinations of these threats.
In 2007, US scientists thought they had revealed the main villain in the piece, by showing that the an imported virus – Israeli acute paralysis virus (IAPV)- was strongly linked to empty hives. But since then, another group showed that IAPV arrived in the US many years before the first signs of CCD were reported. Other related viruses have also been linked to CCD hives, including Kashmir bee virus (KBV) and deformed wing virus (DWV).
To pare down these potential culprits, Reed Johnson from the University of Illinois compared the genetic activity of bees from over 120 colonies, including some affected by CCD and healthy ones that were sampled before the vanishing began. He looked at their digestive systems – one of the most places where infections and environmental toxins would start wreaking havoc.
The analysis didn’t offer any simple answers, but Johnson found some evidence to suggest that CCD bees have problems with producing proteins. In animal cells, proteins are manufactured in molecular factories called ribosomes. These factories assemble proteins by translating instructions encoded within molecules of RNA. Ribosomes themselves are partially built form a special type of RNA known as rRNA. And when Johnson looked at the guts of CCD bees, he found unusually high levels of fragmented rRNA.
This article is reposted from the old WordPress incarnation of Not Exactly Rocket Science. There’s been more work on CCD since, but I’m reposting this mainly because of some interesting follow-up research that will I will post about tomorrow.
In 2006, American and European beekeepers started noticing a strange and worrying trend – their bees were disappearing. Their hives, usually abuzz with activity, were emptying. There were no traces of the workers or their corpses either in or around the ghost hives, which still contained larvae and plentiful stores of food. It seemed that entire colonies of bees had apparently chosen not to be.
The cause of the aptly named ‘Colony Collapse Disorder’, or CCD, has been hotly debated over the last year. Fingers were pointed at a myriad of suspects including vampiric mites, pesticides, electromagnetic radiation, GM crops, climate change and poor beekeeping practices. And as usual, some people denied that there was a problem at all.
But a large team of US scientists led by Diana Cox-Foster and Ian Lipkin have used modern genomics to reveal a new villain in this entomological whodunnit – a virus called Israeli Acute Paralysis Virus or IAPV. By and large, the team found that where there was IAPV, there was CCD. The virus and the affliction were so stongly connected that Cox-Foster and Lipkin estimated that a hive infected with IAPV had a 96% chance of suffering from CCD. Once infected, the chances of a colony collapsing shot up by 65 times.