Evolution is adaptation over time. Not complicated to "prove" on a small
scale; chemical resistance is but one in a long list of adaptations by
mites, continuing their progress on the evolutionary scale.  Chance is but
one mechanism in evolution - it is not at all in opposition to it. When you
only study the final result, then chance seems to be unlikely as a factor.
When studying the entire process, chance is seen as one of the most powerful
mechanisms of evolution.

-----Original Message-----
From: Peter Borst

On another note, one must be very careful when invoking evolution as
a mechanism. I often hear that such and such a species "evolved" to a
certain point -- "mites evolved to reproduce in drone cells".
Evolution, adaptation and resistance are very complicated  processes
and difficult to prove. One must give equal attention to such things
as *chance* and *opportunism*.