2014-15 Survivor Stock Study
Background: Since 2009, the Marin Beekeepers Association has been tracking honeybee statistics. The data collected has shown an average annual reported loss of 46% of honeybee colonies. Locally adapted stock (in the form of splits and) and early season swarms (presumably winter survivors) have consistently shown better rates of survival. But how are they doing it?
Purpose: To study the mechanisms, by which untreated colonies might be controlling varroa mite levels, particularly to attempt to document unusual broodless periods observed in bees in Marin and to determine if there is any correlation between varroa mites and periods of brood cessation when food resources are available. Broodless periods – such as those created when colonies in colder climates shut down brood production during winter months or created by some colonies during times of dearth – assist in reducing mite populations. The relatively mild winters and nearly year round nectar and pollen availability in Marin (particularly southern Marin) mean that bees tend to produce brood throughout the year. The observation by local treatment free beekeepers that some of their colonies appear to be creating broodless periods when one would not expect – such as during nectar flows – begs the question of whether or not these periods are an adaptation of the bees that helps to deal with varroa mites.
Why is This Important? If this is a mechanism for helping to control varroa, this knowledge can help beekeepers adjust their management practices to support this behavior. Conventional beekeeping wisdom dictates that colonies found to be broodless during periods of pollen and nectar availability are queenless and should be requeened or combined with another colony.