For several years, bee keepers have been seeing the honey bee colonies totally wiped out. Referred to as Colony Collapse Disorder (CCD) it has been a cause for concern for several years.
The exact cause, and how to combat it, have been the subject of vigorous debate.
Researchers from the Department of Agriculture have found that when colonies are infected with both a fungus (Nosema cerenae) and a group of RNA viruses, there is a strong chance of CCD.
Once the viruses become prevalent in a colony, they spread quite rapidly both by contact among the bees and often by a parasitic [Varroa destructor] mite that lives on them.
“We’ve been able to see the viruses move within that mite and actually be transmitted from bee to bee by the mite,” said Dr Evans.
As for the fungus, it is transferred by the insects’ excretions, he said.
“Nosema ceranae will germinate in the stomach of the bees, work its way into the rest of the body and exit when it’s excreted. So when the sick bees defecate in the colony or near a colony, other bees accidentally pick up the spores of the fungus and ingest them – and that restarts the cycle,” explained the scientist.
But that may not be the whole story. There is still the question of what has suddenly made the colonies so much more susceptible to the pathogens. One theory is that it is a combination of factors causing stress in the hives. The stress factors include increased use of pesticides, poor nutrition and long travel times.
“The whole approach to controlling pests with pesticides has really shifted [in the past few years] – for instance, now corn seeds, before they are planted, are dipped in pesticides,” said Mr Mendes.
“There’s research that says that it’s not supposed to affect the pollen and the fruit – well, we’ve done some analysis with our citrus trees and we have found levels of the poison in the pollen that the bees are feeding to their young.”
While some beekeepers have had success with increasing protein and otherwise improving nutrition for the bees. ultimately CCD is another indication of our need to return to more sustainable methods in what we do