September 28, 2012
Dying Honey Bees Fight Colony Collapse With Resistance Genes
Brett Smith for redOrbit.com - Your Universe Online
As the phenomenon known as Colony Collapse Disorder (CCD) continues to plague North American honey bees, apiologists have been scrambling to find both the cause and the cure for the disappearance of millions of insects.
According to a report in the open access journal Genome Biology, new research from a group of Canadian scientists may have found a major culprit responsible for the disorder: a parasitic mite known as Varroa destructor.
Researchers found that the tiny mites suck the blood of larval and adult bees, which leaves them weak and more susceptible to infections. This parasitic relationship also increases the risk of viral disease among hosts that already have a relatively weak immune system due to a low number of immunity genes compared to more solitary insects like flies.
The researchers also report that the bees are not without recourse in their battle against the V. destructor menace. At a research apiary in Grand Forks, British Columbia, members of the honey bee colonies were observed removing diseased or parasitized larvae from their brood cells and removing mites from remaining larvae.
This behavior prompted the research team to examine protein differences in larvae and adults that could serve as a signal for the hygienic insects. After analyzing approximately 1,200 proteins, the team found that several proteins that were associated with both the opening of brood cells and the elimination of larvae. Some of the proteins they identified were signals the probably assisted the adult bees in locating infected larvae in a brood.
In addition to identifying the key proteins in adult bees that are responsible for their hygienic behavior, experts spotted a protein in damaged larvae that could also play a key role and uncovered several other larval proteins that help fight off or resist infection.
The study´s lead scientist said he hoped the identification of these proteins could translate into more robust and disease resistant bee colonies.
"Bee keepers have previously focused on selecting bees with traits such as enhanced honey production, gentleness and winter survival,” said Leonard Foster from the University of British Columbia. “We have found a set of proteins which could be used to select colonies on their ability to resist Varroa mite infestation and can be used to find individuals with increased hygienic behavior."
“Given the increasing resistance of Varroa to available drugs this would provide a natural way of ensuring honey farming and potentially survival of the species,” he added.
The discovery could play a key role in reversing the fortunes of honey bees, which have been devastated by a variety of forces. CCD was first identified in 2006 when beekeepers across the continent began noticing large numbers of the insects disappearing from their hives. Since honey bees are a valuable pollinator of agricultural products, a massive loss of bees could have a huge financial impact on farmers.
After six years of research from many institutions, most experts agree that CCD is caused by nutritional stress factors, pathogens, parasites and pesticides. Many studies, like the one from British Columbia, have offered solutions, but a comprehensive turnaround has yet to occur.