In another thread, Randy said:

"The counts for colonies adjacent to colonies with counts near 40 are often zeroes or 1's."

...and John said:

"Varroa are nearly clonal (as the usual mating is older brother to younger sister)."

I have been mulling over the question of mite behavior for awhile now.  I started thinking about it when I was taught at an EAS meeting some time ago that foundress mites produce offspring that mate with each other.  I wondered:  How can genetic diversity happen in these circumstances?  We all know what happens to humans when inbreeding is practiced.  The same should be happening to inbred mites.  So this summer, I have taken the time to pull drone pupae over entire sides of drone brood frames.  To my surprise, I found some drones had 3-4 foundress mites while others had no mites at all.  There was "mite congestion" in patches on the drone frame.  These "congested" cells would typically have 2 or more foundress mites and many offspring all feeding on one poor drone.

This behavior offers an explanation (at least to me) as to how mites can evolve, as they do need a mechanism to avoid clonal reproduction.  Clonal reproduction is a strategy to practice only when times are good (think spring and bee populations increasing).  However, if all that ever happens is that daughters breed with sons, the only way genetic variation can occur is through random mutations.  This is not a good way to promote "survival of the fittest".  The best way is to have genetic mixing with other mites at least some of the time, so that the genome can re-sort itself for the best mix of traits.  This would be prudent when times are tough (think bee population growth slowing down).

If mites congregate on occasion in order to improve sexual selection and diversity, then they can develop their own version of resistance to local stressors.

Does anyone know of any studies that might show how mites behave in this way.... whether they are attracted to certain hives at some times of the season (like I have seen they are attracted to certain patches of cells)?  Mite behavior that promotes "mite bomb hives" would mean that selecting for mite resistance in the bees and expecting this will work in all daughter queens will be frustrating at best.

Christina

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