A recent computer graphical model created from data of collected mites in cells published recently in one of the bee mags showed how varrora is concentrated in the center of the brood nest. One can imagine then that where you select drone brood would have a bearing on the results. 

I seem to recall Marla Spivak saying that drone brood inspection is not a very good indicator of mite loads as compared to the alcohol wash that Bob was suggesting. Often mites are left in the cell also and unless you are looking closely there may be mites there but not on the removed larvae or pupae sample. 

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html

Access BEE-L directly at:
http://community.lsoft.com/scripts/wa-LSOFTDONATIONS.exe?A0=BEE-L