> On Sep 10, 2015, at 1:51 PM, Christina Wahl <[log in to unmask]> wrote:

> 

> This is back to my question about mite behavior.  I wonder if they somehow manage to converge on a specific hive regardless of whether bees are drifting into that hive too.  Tom Seeley has not observed such intense mite populations in isolated forest hives, so maybe this behavior (mite bomb) is limited to high-density apiaries.



I think we don’t really know very much about how mites are dispersed. The theories have all referred to robbing of sick hives and drifting. I don’t think in-apiary drifting can account for a sudden spike in mite populations. But if bees are all robbing out sick hives, this cannot account for the difference between the high levels in apiaries vs the low levels found in isolated hives. 



What would account for both of these is a theory where the bees from a collapsing hive leave to seek other healthy hives. In this way, the varroa would be able to abandon the sinking ships and get on board the floating ones. There are other examples of parasites driving their hosts into behaviors to enhance their propagation, so it isn’t far fetched. It would be very difficult to prove, though.



I have seen hundreds of hives that were booming in August, made a couple of full deeps of honey, and then the bees just vanished. In fact, when people started talking about colony collapse in 2006, I thought “what’s new about that?” Untreated hives always collapsed in fall. The question for me was “where did the bees go?” If they flew off to look for healthy hives, they would be more likely to find an apiary than an isolated colony in a tree in the woods.



Obviously, I have no evidence to support this theory, other than what I have already presented. But the fact remains, even in hives where mites are low during mid-summer, there is a spike in mite population in late summer to early fall, which appears to come from external sources. By the way, we see a similar thing with ticks. In early spring they seem to drop off the deers and try to get picked up by new hosts. This also happens again in the fall. 



P





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