Robbing occurs when bees from one colony enter another and “steal” the honey. This is the anthropomorphic view (seen from the human eye). It has been suggested, however, that robbing is nothing more than human induced foraging strategy adopted by bees in close proximity to each other’s colonies. In nature, there are never many hives concentrated in one area. Robbing is particularly virulent during times of nectar scarcity (dearth).
The beekeeper must be ever vigilant when feeding honey bees during nectar dearths to avoid letting honey bees entering other hives. Robbing is a major way the devastating disease American foulbrood is spread via spores in the infect colony. When robbing gets started, it can also lead to severe stinging incidents. The excitement level shown by honey bees engaged in a large robbing episode is something not soon forgotten. Whole apiaries have been reportely destroyed in a few instances. Some robbing probably goes on all the time between colonies. This endemic robbing level only becomes epidemic when conditions are right.
Once robbing has begun, it is almost impossible to stop. About the only thing a beekeeper can do is put colonies back together and reduce their entrances, as well as those of nearby colonies, letting the behavior run its course. The best ways to avoid robbing is to keep colonies strong so they can defend themselves and never allow bees free access to honey, syrup drippings or wet combs. Robbing will always be minimal during a nectar flow.
Beginners often unwittingly allow robbing to build up when they keep colonies open for long periods while making inspections or taking off honey. Weak colonies are particularly vulnerable to robbing. The best way to protect such colonies is to reduce entrance openings with wooden blocks, grass or straw. In queen rearing operations, specialized “robbing screens” are used to protect small colonies or nuclei from invasion.
Potential robbers can often be found at the rear of hives attempting to enter through cracks. Other signs of robbing include unnecessary excitement and large numbers of bees “inspecting” other colonies. Cappings on the bottom board are also a sign. Robbing bees have been anthropomorphically characterized as “furtive and nervous,” or “black and greasy.” In the latter cases, many of the bee’s hairs have been pulled out by numerous guard bee maulings.
When entering an apiary, the beekeeper should always take stock of the robbing potential and maintain a constant awareness of the excitement level of the bees. If robbing gets out of hand, both bees and beekeeper suffer. Controlling this destructive behavior is one of the quintessential acts of good beekeeping.
Although care should be taken to ensure that cracks or holes don’t exist in hives which incite robbing, free air exchange is vital to a colony’s health. This is not always apparent, particularly to beekeepers in colder climates. See more about robbing via the World Wide Web.