I once ran a study of mites in bees, sampled every month for 48 months, 16 colonies per location, multiple locations, all in varying compass directions around a smelter in East Helena, MT. Results were that mites took out the colonies faster, at the locations nearest the smelter. The point is, we had to open and sample bees every month. We'd pop the lid, pull the frame closest to the outside of the cluster, vacuum up bees from outside of cluster to look for tracheal and varroa mites. Colonies farthest from smelter latest for a full two years, also had fewest mites. Obviously our distant control were not harmed by the intrusions. We tried to avoid cold wind, but we opened these in below freezing weather, many times. We did our best to not break the cluster. But we pulled lids, pulled frames, sucked up bees - all in winter conditions, snow on ground, etc. Hives were wrapped in black roofing felt, and we always tried to work about mid-day. Rule was to never open them near end of day - we wanted to give bees some time to recover before nightfall. Jerry *********************************************** 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