> >Spanish researchers continue to insist that Nosema alone can cause colony
> collapse (this is not CCD per se).


Not following you here Pete.  N apis has long been observed to "cause" the
signs of CCD--a sudden disappearance of the adult population, leaving a
handful of young bees and the queen on brood.  The Spanish team observed
similar signs when 50% of the adult population became infected with N
ceranae.

In California, I continue to observe colonies collapsing with CCD signs
when the infection rate with N ceranae reaches about 70% of the bees.

Now I'm not saying that N ceranae "causes" CCD, since it could be an
opportunistic pathogen following immune suppression by a virus or something
else.  But my observations support that it can cause the behavior in bees
that results is sudden colony depopulation.

The data from last winter's Monsanto trial should help to answer the
question of what the progression of pathogens is that led the the collapse
of colonies over winter and spring.

 > The best established criteria for proof of causation were formulated by
Loeffler and Koch in the 1880s. Popularly known as Koch’s postulates, these
criteria require that an agent be present in every case of the disease, be
specific for the disease and be sufficient to reproduce the disease after
culture and inoculation into a naive host.

In my original field trial with Beeologics, the introduction of a
particularly virulent strain of IAPV isolated from an operation collapsing
with CCD symptoms, resulted in creating CCD signs in 71 out of 72 healthy
colonies.  These colonies were also infected with N ceranae, but the
informal controls did not suffer the same fate, despite also being infected
with N ceranae.

The above observations lead me to believe that infection by certain viruses
(or strains thereof) can start the positive feedback loop that can lead to
sudden colony depopulation, as described in my flow chart at
http://scientificbeekeeping.com/sick-bees-part-2-a-model-of-colony-collapse/

-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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