The Carniolan honey bee (Apis mellifera carnica, Pollmann) is native to Slovenia, southern Austria, and parts of Croatia, Bosnia and Herzegovina, Serbia, Hungary, Romania, and Bulgaria. It is favored among beekeepers for several reasons, not the least being its ability to defend itself successfully against insect pests while at the same time being extremely gentle in its behavior toward beekeepers. These bees are particularly adept at adjusting worker population to nectar availability. It relies on these rapid adjustments of population levels to rapidly expand worker bee populations after nectar becomes available in the spring, and, again, to rapidly cut off brood production when nectar ceases to be available in quantity.