< The researchers
are working on the theory that the reason some colonies are wiped out
while others remain healthy could be down the genetic diversities of
the hives. (Honeybees with queen marked; Credit: Bill Hughes) One
possibility is that the loss of honeybees means that the number and
variety of potential mates for a queen is becoming too low to maintain
genetic diversity and therefore disease resistant populations. Says
Dr Hughes: “Given the choice, queen honeybees will typically mate with
up to 12 different male partners in a matter of minutes and some with
over 20. The record is the giant Asian honeybee whose queens normally
mate with well over 40 males - and in one case was found to have mated
with over a hundred.” The Leeds scientists will be examining the
question of genetic resistance by studying honeybee reactions to a
common fungus parasite called Chalkbrood, under carefully controlled
laboratory conditions.
Dr Bill Hughes, from the Faculty of Biological
Sciences at the University of Leeds, says: “By making sure queens mate
with enough genetically variable males, we may be able to boost
resistance levels and so protect our honeybee populations from disease
attacks like the ones we have seen hitting the US.”
The fungus, already found in the
majority of UK hives, infects and ‘eats’ larvae, giving them a chalky
appearance. Individual larvae die but the parasite rarely kills the
whole colony.
In 2008, US average losses of honeybee colonies
were 35%, with some beekeepers losing 90% of their colonies. A
contributing factor to these high levels of honeybee deaths may have
been a virus. However the same virus has been found in other countries
yet does not seem to cause the same problems.
Dr Hughes and
his team think infections by hidden parasites in genetically
susceptible bees may be combining with other factors to produce a
lethal ‘perfect storm’ which overwhelms their defences.
Honeybee
survival is vital to the protection of our food supplies because they
pollinate up to a third of the food we grow in the UK.
The
project, which has received just under £500,000 in funding from the
Natural Environment Research Council, is due last for three years.
Collaborators include the UK Government’s National Bee Unit based near
York and the University of Copenhagen.>>
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