First of all, thankyou all for this most excellent discussion thread. It is a shame, Jerry, that your students' research was not published. Their findings are most interesting to anyone tasked with the nuts and bolts work of managing colonies and apiaries. There are so many simple questions relating to basic bee management practice that do not garner research/publication attention...

We were fortunate some years ago to have a lecture from Gloria DeGrandi-Hoffman of the Tucson Bee Lab. They had just collated the first batch of data from a project looking at mite immigration into colonies and their preliminary results indicated that 80% of mite loads came from mites originating outside the colony. Below is a citation from a 2017 paper on the topic from the TBL.

It is possible that in honey bees as in other species, there is a parasite-mediated host response that drives mite-infested honey bee workers to drift at higher than usual rates: great for the Varroa mites, not so great for recipient colonies.

A few of our local beekeepers noted crazy spikes in mite numbers in the fall after what they thought was effective treatment. Some experienced colony collapse as a consequence, in colonies that had before been strong and were expected to do well and winter well. Drift + robbing type mite immigration may be the agent responsible, although for us hobbyists it is difficult or impossible to be certain whether the treatment was ineffective for some reason, or a management practice, or the mites themselves are more virulent for some reason, or whether infested drift bees brought on the apocalypse.

Queens seem to differ in their ability to hold workers: some years ago a friend acquired a number of packages of bees imported from New Zealand and hived a number, in a row, on the same day. Returning to the apiary several days later, one hive had garnered most of the bees from colonies on either side...we could only speculate that these package bees had not only loose affiliation with the queen they were shipped with, but that the "garnering queen" had some special something they all were drawn to...pheromone profile??

Randy, your idea of swapping colony positions to reveal which has the queen who inspires most loyalty may be another tool to "proof" queens in our little queen breeding project, locally.

Citation: Messen, K., Hoffman, G.D., Castillo-Chavez, C., Kang, Y. 2017. Migration effects on population dynamics of the honeybee-mite interactions. Mathematical Modeling of Natural Phenomena. 12(2):84-115. doi: 10.1051/mmnp/201712206.

Interpretive Summary: The survival of honey bee colonies is undermined by numerous factors, but most notably the parasitic Varroa mite (Varroa destructor Anderson and Trueman). A recent field study showed that migration of Varroa into hives on foraging bees greatly contributes to the rapid growth of mite populations in colonies. Motivated by this finding, a simple two-patch honey bee-Varroa model was constructed to explore how foraging behavior of honey bees in the presence of Varroa infested colonies might affect the population dynamics of honey bees and mites. The model revealed that when there are low rates of mite migration between patches with low mite populations, colonies and mites can coexist in both patches suggesting that low-level migration of mites on foragers could be a successful dispersal strategy for Varroa. However, high migration rates from infested to uninfested patches caused a rapid growth of the Varroa population in the uninfested patch, which in turn had a negative feedback on colony growth and survival. The theoretical framework for the interactions of colony and Varroa population dynamics provided by the model underscores the importance of area-wide Varroa control, because colonies with low mite infestations cannot survive when they are surrounded by highly infested hives. 

             ***********************************************
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