Good lecture for discussion, Charles!  Thank you.  It tells us that cyhalothrin affects feeding and fat stores in bees.


We learn:

Bees with poor nutrition have more viral problems.


Bees that have viral problems have a higher tendency to abandon their colonies (CCD?).


Bees with viral stress and nutritional stress have higher mortality.


Toth and company saw that dandelion pollen caused higher mortality:  They were surprised...so they had it tested...and found that dandelion pollen had higher levels of cyhalothrin, a pyrethroid pesticide.  This higher level of exposure, they learned, comes from spillover due to nearby crops...the dose was reported as "sublethal".  They found that this contaminated dandelion pollen was rejected by bees in choice trials, even actively pushed away.  Bees that had no choice but contaminated dandelion pollen had less fat stores. Bees also ate less of it.


Conclusion:  Vicious cycle of poor nutrition, pesticides, viruses lead to unhealthy bees.


See my recent Lundgren posts.


In the ESHPA meeting I attended this weekend, where I listened to Lundgren, I was surprised to learn from other talks at the same meeting that commercial beekeepers are applying protein patties ALL SUMMER!  This was never the case "back in the day". (I am a daughter of commercial beekeepers, and based on what I know about beekeeping practices since the late 1800s when my family began beekeeping, protein supplementation on hives all summer is new).  Nowadays, I learned that commercial beekeepers routinely supplement protein to overcome colony stress throughout the year.   In my opinion, this is a "new" form of management.


We also learned at ESHPA that the number of colonies has increased in the USA, but honey production has decreased. There seems to be a correlation here....nutrition on limited forage (monocultures) is affecting colony success...the landscape has changed.


In the end, Toth shows what Lundgren tells us will happen....HIGH DIVERSITY IMPROVES COLONY SUCCESS.   She then quotes Lundgren studies.  They then filtered their results based on mite levels.  More mites = more viruses, and that wasn't a surprise.   So Toth group evaluated samples, and filtered samples to reanalyze data.  Presence of mites made a big difference.  Mites absent showed that bees are better off on low cultivation than high cultivation areas.


Toth concluded that interactions are very important.  "the devil can be in the interactions".  She said a wider diversity of species will help.


All this dovetails very nicely with the Lundgren talks I reported on earlier today.

Christina

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