! Those of us who kept bees through the initial collapse of feral populations due to varroa remember the effect well--our colonies, made nearly mite-free by application of Apistan strips, were simply overwhelmed by an influx of mites from the collapsing feral colonies. Today, the same likely happens in urban areas containing large numbers of treatment free beginning beekeepers. As their colonies collapse from varroa, they flood the neighborhood with mites by drifting and robbing behavior of bees. I have been pondering this for months now. While some of what Randy points out makes perfect sense in areas with many yards, the math of the mite counts going up in hives does not work in what I consider to be the average area. Here is why. Please point out my errors in thinking. The base assumption is that mite numbers are doubling or better. That would entail pretty close to literally every mite from a collapsing hive to immigrate (depending on the number of brood cycles after immigration and before the count) This also would require that roughly 1/2 the hives in a given area collapsed. This is something I have never seen. Fall collapse (aug/sept) are non existent here. Always some failure to thrives, but they don't collapse until later in the season. Those hives with high mite counts are starting to fail, but given deformed wings are a main source of this issue, obviously these bees will not be part of the problem. Given the higher number of mites on nurse bees, this theory also requires the mites to make a jump to foragers and pack the traveling bags. It seems a stretch that mites do this as a matter of intent. Yes I realize that younger and younger bees are recruited to forage, but also recognize they don't all drift to other hives. Alternative thought, 2 fold, first as mentioned elsewhere the amount of bees drops a bit, thereby increasing the infestation rate, and secondly and I think much more mathematically viable, is the slowdown in brood chamber temps. A lower temp will increase the capped time by 24 hours this is going to allow around a 25%increase in the number of mites per cycle, about 2 rounds of that and you have a huge issue, and on top of that the increased mite load (5 mature mites instead of 4) means that the brood survivability dropped and again back to less bees per mite. It seems to me to prove or disprove, would take a bit of genetic monitoring of mites.. In the end I am not sure it really matters. But it is an interesting discussion. It seems to me the studies so far show a snapshot in time and location. Dr. Seelys work seems closer to what I think the majority of the country sees. I was looking at his work on Drifting in general, I did not see his work on drifting as it pertains to mite load increase? Charles *********************************************** 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