> Similar was the recent NBC segment on bee pesticide kills, which showed
> crawling bees supposedly dying from clothianidin dust.  Anyone could
> clearly see that there was none of the twitching indicative of
> neonicontinoid poisoning.  Such lethargic crawlers are indicative of a
> heavy infestation by nosema, not from neonic poisoning!



http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2847190/ (Full Paper)
Interactions between Nosema microspores and a neonicotinoid weaken
honeybees (Apis mellifera)

Abstract
Global pollinators, like honeybees, are declining in abundance and
diversity, which can adversely affect natural ecosystems and
agriculture. Therefore, we tested the current hypotheses describing
honeybee losses as a multifactorial syndrome, by investigating
integrative effects of an infectious organism and an insecticide on
honeybee health. We demonstrated that the interaction between the
microsporidia Nosema and a neonicotinoid (imidacloprid) significantly
weakened honeybees. In the short term, the combination of both agents
caused the highest individual mortality rates and energetic stress. By
quantifying the strength of immunity at both the individual and social
levels, we showed that neither the haemocyte number nor the
phenoloxidase activity of individuals was affected by the different
treatments. However, the activity of glucose oxidase, enabling bees to
sterilize colony and brood food, was significantly decreased only by
the combination of both factors compared with control, Nosema or
imidacloprid groups, suggesting a synergistic interaction and in the
long term a higher susceptibility of the colony to pathogens. This
provides the first evidences that interaction between an infectious
organism and a chemical can also threaten pollinators, interactions
that are widely used to eliminate insect pests in integrative pest
management.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3310228/ (Full paper)
Parasite-insecticide interactions: a case study of Nosema ceranae and
fipronil synergy on honeybee
Abstract
In ecosystems, a variety of biological, chemical and physical
stressors may act in combination to induce illness in populations of
living organisms. While recent surveys reported that
parasite-insecticide interactions can synergistically and negatively
affect honeybee survival, the importance of sequence in exposure to
stressors has hardly received any attention. In this work, Western
honeybees (Apis mellifera) were sequentially or simultaneously
infected by the microsporidian parasite Nosema ceranae and chronically
exposed to a sublethal dose of the insecticide fipronil, respectively
chosen as biological and chemical stressors. Interestingly, every
combination tested led to a synergistic effect on honeybee survival,
with the most significant impacts when stressors were applied at the
emergence of honeybees. Our study presents significant outcomes on
beekeeping management but also points out the potential risks incurred
by any living organism frequently exposed to both pathogens and
insecticides in their habitat.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3264871/ (Full Paper)
Pesticide exposure in honey bees results in increased levels of the
gut pathogen Nosema

Abstract
Global pollinator declines have been attributed to habitat
destruction, pesticide use, and climate change or some combination of
these factors, and managed honey bees, Apis mellifera, are part of
worldwide pollinator declines. Here we exposed honey bee colonies
during three brood generations to sub-lethal doses of a widely used
pesticide, imidacloprid, and then subsequently challenged newly
emerged bees with the gut parasite, Nosema spp. The pesticide dosages
used were below levels demonstrated to cause effects on longevity or
foraging in adult honey bees. Nosema infections increased
significantly in the bees from pesticide-treated hives when compared
to bees from control hives demonstrating an indirect effect of
pesticides on pathogen growth in honey bees. We clearly demonstrate an
increase in pathogen growth within individual bees reared in colonies
exposed to one of the most widely used pesticides worldwide,
imidacloprid, at below levels considered harmful to bees. The finding
that individual bees with undetectable levels of the target pesticide,
after being reared in a sub-lethal pesticide environment within the
colony, had higher Nosema is significant. Interactions between
pesticides and pathogens could be a major contributor to increased
mortality of honey bee colonies, including colony collapse disorder,
and other pollinator declines worldwide.



Juanse Barros J.
APIZUR S.A.
Carrera 695
Gorbea - CHILE
+56-45-271693
08-3613310
http://apiaraucania.blogspot.com/
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