Showing posts with label Honey Bee. Show all posts
Pesticides Confuse Bees : Study Suggests
Posted by Unknown in Beekeeping, Honey Bee, Pesticide, Research and Studies on Tuesday, 14 May 2013
John von Radowitz, PA
Times of Malta
 |
| Insecticides disrupt their learning, threatening survival and reducing pollination |
Commonly used pesticides confuse bees by disrupting the learning circuits in their brains, a study has found.
The effects
could make it harder for bees to forage among flowers for food, thereby
threatening their survival and reducing pollination.
Bees exposed to
two kinds of pesticide were slower to learn or completely forgot
important associations between floral scents and nectar.
The impact of the chemicals increased when they were combined together.
One group of
compounds tested were neonicotinoids, which are related to nicotine and
used around the world to control a variety of pests. The other
pesticide, coumaphos, is employed outside the EU to kill the Varroa mite
that attacks honeybees.
In the laboratory, scientists exposed bees’ brains to levels of the pesticides similar to those found in the wild.
They then
recorded electrical activity from cells from a higher order bee brain
structure called the ‘mushroom body’ which is important for memory and
learning. Forty per cent of a bees’ neurons can be found in the mushroom
bodies.
The results showed that both chemicals targeted this region of the bee brain, causing a loss of function.
Other research
by collaborating scientists showed that up to 30 per cent of honeybees
exposed to combinations of the pesticides for four days failed to learn
and performed poorly in memory tests.
The findings are published in the journal Nature Communications.
Geraldine
Wright, from the University of Newcastle, said: “Pollinators perform
sophisticated behaviours while foraging that require them to learn and
remember floral traits associated with food. Disruption in this
important function has profound implications for honeybee colony
survival, because bees that cannot learn will not be able to find food.”
Christopher
Connelly, whose team at the University of Dundee conducted the brain
recordings, said: “Much discussion of the risks posed by the
neonicotinoid insecticides has raised important questions of their
suitability for use in our environment.
However, little
consideration has been given to the miticidal pesticides introduced
directly into honeybee hives to protect the bees from the Varroa mite.
We find that both have negative impact on honeybee brain function.
“Together,
these studies highlight potential dangers to pollinators of continued
exposure to pesticides that target the insect nervous system and the
importance of identifying combinations of pesticides that could
profoundly impact pollinator survival.”
Bee expert
Francis Ratnieks, professor of apiculture at the University of Sussex,
said: “Bees are wonderful creatures in their own right, and are of
increasing importance to our own food supply through pollination. This
makes it extremely important that we understand what affects their
health and causes declines in their populations.
“It’s no
surprise that insecticides at high concentrations are harmful, but we
don’t know whether the low levels of neonicotinoid insecticides in the
nectar and pollen of treated plants, such as oil seed rape, are harmful
in the real world.
“This new
research gives us basic knowledge of how these insecticides affect
specific cells in the honeybee brain that play a role in honeybee
learning and behaviour.”
Reduced numbers
of flowers and wildlife habitats due to the intensification of farming
was probably the most important factor behind bee loss.
Ratnieks added that coumaphos could not legally be used to control Varroa mites in the UK and EU.
Pesticides, Habitat Loss, Parasites Blamed for Bee Loss
Posted by Unknown in Beekeeping, Colony Collapse Disorder, Honey Bee, Report, USDA on Wednesday, 8 May 2013
WASHINGTON -- A new federal report blames a combination of problems for a mysterious and dramatic disappearance of U.S. honeybees since 2006.
The intertwined factors cited include a parasitic mite, multiple viruses, bacteria, poor nutrition, genetics, habitat loss and pesticides.
The multiple causes make it harder to do something about what's called colony collapse disorder, experts say. The disorder has caused as much as one-third of the nation's bees to just disappear each winter since 2006.
Bees, especially honeybees, are needed to pollinate crops.
The federal report, issued Thursday by the Agriculture Department and the Environmental Protection Agency, said the biggest culprit is the parasitic mite varroa destructor, calling it "the single most detrimental pest of honeybees."
The problem has also hit bee colonies in Europe, where regulators are considering a ban on a type of pesticides known as neonicotinoids that some environmental groups blame for the bee collapse. The U.S. report cites pesticides, but near the bottom of the list of factors. And federal officials and researchers advising them said the science doesn't justify a ban of the pesticides yet.
May Berenbaum, a top bee researcher from the University of Illinois, said in an interview that she was "extremely dubious" that banning the pesticide would have any effect on bee health. She participated in a large conference of scientists that the government brought together last year to figure out what's going on, and the new report is the result of that conference.
Berenbaum said more than 100 different chemicals -- not just the pesticides that may be banned in Europe -- have been found in bee colonies. Scientists find it hard to calculate how they react in different dosages and at different combinations, she said.
Some of these chemicals harm the immune systems of bees or amplify viruses, said Penn State University bee expert Diana Cox-Foster.
At a news conference Thursday, Sonny Ramaswamy, a top USDA official, said the scientific consensus is that there are multiple factors "and you can't parse any one out to be the smoking gun."
USDA bee researcher Jeff Pettis also cited modern farming practices that often leave little forage area for bees.
