* I believe any theory which singles out the sole cause of bee die-offs will
fail to reflect the actual situation. There are many interconnected factors.
If the bee population is inherently weakened, whether by varroa, nosema, or
inbreeding, it will be very difficult to prove that an additional burden,
such as barely detectable amounts of imidacloprid, was the straw that broke
the camel's back. But, good luck.

> Wuerzburg, Germany - The collapse of bee populations, which is worrying
farmers in many nations, has multiple causes including a loss of wild
countryside which used to offer the insects a varied diet, a German biology
professor said Wednesday. Some German apiarists lost their entire stock of
bees in the past winter. The direct cause of most bee deaths is the varroa
mite, which infects bees, but the indirect causes for the insects' lack of
immunity to parasite and illnesses were highly varied, Tautz said, blaming
breeding programmes that had created docile, weak bees. "Nowadays it only
takes one tenth as many mites to wipe out a swarm as it took a decade ago,"
he said.

Citation: "Bee population collapse: multiple causes, says German expert"
http://tinyurl.com/3t2xtp



> A population can become extinct by chance, if its environment is highly
variable or if it happens to suffer a few bad years in a row. It is easy
enough to imagine situations in which low densities just make things
progressively worse. This effect may be due to generic impacts like
inbreeding or limitations on the availability of mates due to geographic
dispersion, or species-specific traits such as the breakdown of
anti-predator herd guarding or the failure of male bird breeding arenas
(called leks) to attract females if they are too small. Such problems, where
low numbers of individuals in a population leads to a self-perpetuating loss
of demographic, genetic, or ecological fitness, are called "Allee effects". 

Citation: Brook BW (2008) "The allure of the few." PLoS Biol 6(5): e127.
doi:10.1371/journal.pbio.0060127

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