>The resistance mechanism is believed to come from a
> change in the sodium channel (do not ask me to explain it!), which is a 
> change which has no cost to the mite.

Italian studies (cited in my article in ABJ) indicate that the mite pays a 
considerable cost.  The reproduce only about half as rapidly.
Randy Oliver 

******************************************************
* Full guidelines for BEE-L posting are at:          *
* http://www.honeybeeworld.com/bee-l/guidelines.htm  *
******************************************************