There is something that i think is missing from this thread. Tina mentioned that the bees are eating the pollen from last summer.
If your weather was a crazy as our weather was last year, there is a good chance that the pollen has no protien....bear with me here please...
two years ago we had massive rains...I am in Manitoba just above ND. The rains did not stop. We got our hay tested and the results came in Jan 09. The hay had the protien level of straw, which if you understand anything about feeding cows...no protien for the cows. The TDN...total digestable nutrients was as i said like feeding straw, no value. We ended up supplementing the cows so they could make it to calving, then rebreed on time and still feed a calf. Had we not done that, the cow might have calved a really weak calf, the calf performed weakly and the dam would more than likely not bred back on time
...what does this have to do with bees....
our bees foraged on the same fields the cows did. I have no scientific data to back this up, however, if the hay was garbage, it stands to reason that the stressed out plants pollen was garbage. I mean the apple will not fall far from the tree.
...what does this have to do with bees
bees that feed on stressed out plants will not get all the TDN they need to survive. Basically, the pollen had the TDN or protien of straw.
If a cow who is 1200+ pounds can not survive on straw, can not raise a healthy calf on straw, and can not breed back...how can we expect the bees to?
So lets fast forward to the summer of 2009
again the plants are stressed. Too much water, not enough water = not enough TDN in the pollen where the bees get the protien. Add to it the # of no fly days due to the poor weather, add to it the incredible honey flow when the bees should have been preparing for winter...which shortens their life span ( a forage lives less time if the bee is gathering in the summer than when trying to keep warm over the winter) . So you have the young bees who were meant to grow up and over winter in a cluster now foraging when they were to be preparing for winter. Everything was thrown out of whack.
Is it any wonder we have hives crashing at this point, based from a weather related nutrition stand point, I would say NO. Would this be a stress which would allow other diseases to become more prevailent...yes.
The weather stresses, the feed stresses will lower the disease threshold. So for example...If mite pressure at September 15th was 2%...in a normal year, 2% would be acceptable and wintering success would be good. However, with the stress on the bees with the odd fall flow, and with the lack of protien in the summer flow, that 2% might be above the threshold for mite pressure. Since now the stress is protien, an odd fall and mites, the threshold for the bees to withstand any nosema type will now instead of 1 000000 spores could be 500 000 spores or less.
For us as beekeepers to be surprised at bee losses this spring is crazy....again back to the addage everything we do here and now affects our bees 6 months to a year down the road. This includes weather, plant stress, mite loads and disease pressure.
Please, we need to remember, "just because bees brought in pollen, does not mean the pollen had the protien in it." If a plant is stressed due to weather or even plant pests...like lagus bugs or alfalfa weavles on alfalfa, the plant will not produce the "quality" of protien it normally does. The volume will be there, the but the quality will not.
Just a reminder for those who are not ag growers, plants in a field take several years to recover from stresses...just look at the perennials in your garden.
Cows take two years to recover from a bad summer/winter (drought/flooding, poor quality hay). Why should bees be any different. Plants need atleast a year if not more to recover from a bad year. Maybe if we took a look at this we might realize nutrition has alot to play---or the lack of nutrition.