Due to hot and dry weather in many areas, beekeepers are already messing with robbers. I’ve heard sad stories from beekeepers whose full honey supers suddenly turned up empty, and others whose smaller colonies were wiped out. This is not unusual, but it can bewilder new beekeepers.
Besides taking the honey, the presence of robbing bees attracts wasp predators, especially yellowjackets and hornets, who dine on all aspects of a beehive: bees, brood, honey, and bee bread. Once they get started, both robbers and wasps are hard to stop, so prevention is key.
Having lost hives to these predators myself, I believe in reducing entrances early—much earlier than seems necessary. If you think of an entrance of a source of ventilation, and keep it wide open, you are more apt to get caught by a robbing frenzy.
Think of an entrance as an entrance for everyone—your bees, other bees, and predators. If you want ventilation, use alternate devices such as a screened bottom board, screened inner cover, screened ventilation ports, or similar. A large entrance is not ventilation—a large entrance is trouble.
Where I live, I reduce the entrances when I remove the honey supers at the end of June. The key to entrance size is to make it commensurate with the size of the colony.
Most standard entrance reducers come with two hole sizes, one about 3/4-inch long, and one a little less than five inches long. I sometimes use the longer opening for large colonies, but I rarely use the 3/4-inch size except for the smallest of colonies. Instead, I like a two-inch opening for most hives during a dearth. You can make them easily out of a piece of 1-by-1. I made a bunch one year with various hole sizes. When it comes times to reduce, I carry the bucket of reducers with me and select a size on a colony-by-colony basis.
Last week I was near my smallest hive when I noticed a commotion on the landing board. When I got closer I was amazed to see this little colony with a much-reduced entrance had taken down a bald-faced hornet. Way to go! They were in a tizzy trying to remove it, with two to three bees pushing and dragging to no avail. (After I shot the photo, I gave them a hand.)
The other thing that works well is a robbing screen. I have some that I bought online, but I think they are too complicated and too expensive. I don’t need all the adjustable entrances and swinging doors, so I’m in the process of making a simpler design which I will share once I’ve tested it. Remember that robbing screens work just as well for yellowjackets and hornets as they do for robbers, so don’t hesitate to use them.
Robbing bees: questions and answers
What is robbing?
Robbing is a term used to describe honey bees that are invading another hive and stealing the stored honey. The robbing bees rip open capped cells, fill their honey stomachs, and ferry the goods back home. They will fight the resident bees to get to the stores and many bees may die in the process.
When does robbing occur?
Robbing can occur anytime during the year, but it is most evident in the late summer or early fall, especially during a nectar dearth. Robbing can often be seen in the early spring as well, most frequently before the first major honey flow.
Why does robbing occur?
Honey bees are compulsive hoarders. They will collect nectar or honey from any source they can find, and that includes a poorly guarded or weak hive. Personally, I think “looting” is a better description because, like human looters, they tend to prey on the weak and vulnerable, especially a hive with a problem.
Think of it like this: It is a hot August afternoon. It hasn’t rained in weeks. The flowers are long past their peak and the few that remain are crispy. A gang of bored workers with too much time and not enough to do is hanging out, looking for trouble. Suddenly, one of the gang picks up on a scent . . . sweet! It’s coming from a nearby hive where the beekeeper has spilled some syrup. A few scouts check it out and believe they can overpower the lethargic guard bees lounging in the heat. Within minutes the dancers post directions on CombBook and the siege is on.
How can I recognize robbing?
Sometimes a weak hive will suddenly come to life. You, a new beekeeper, are ecstatic because a hive you thought was dying is now thrumming with activity—bees are everywhere. You think the colony has finally turned itself around. But when you go back the next day, no one is home. The honey frames have been stripped clean, bees lie dead on the ground, and the small colony is decimated.
At other times, the signs are more subtle:
- Fighting bees tumble and roll—sometimes on the landing board, sometimes in the air.
- Dead bees lie on the landing board or on the ground in front of the hive.
- Robbing bees can often be seen examining all the cracks and seams in a hive, even at the back and sides.
- Robbing bees are often accompanied by wasps that are attracted to the dead bees as well as the honey.
- Some of the bees in the fray may appear shiny and black. This appearance is created when the bees lose their hair while fighting. Both attackers and defenders may have this appearance.
- Robbing bees never carry pollen on their legs.
- Robbing bees often sway from side to side like wasps, waiting for an opportunity to enter the target hive.
- Pieces of wax comb may appear on the landing board as the robbers rip open new cells.
- Robbing bees are louder than normal bees.
- Because robbing bees are loaded down with honey when they leave the target hive, they often crawl up the wall before they fly away and then dip toward the ground as they take off. This may not be immediately obvious, but if you study them for a while, you can see it.
What can I do to prevent robbing?
It is much more effective to anticipate robbing and take preventive measures than to try to stop it once it starts. Here are some strategies that may work—at least some of the time.
- Reduce entrances at the first sign of a nectar dearth. Bees can successfully defend their hive if they have a large enough population and a small enough entrance.
- Many beekeepers have observed that Italian bees rob more often than other sub-species. If you keep Italians, you should be more vigilant.
- It appears that queenless hives are more vulnerable to robbing than queenright hives. Make sure all your hives are queenright as robbing season approaches.
- Entrance feeders seem to promote robbing more than other feeders, probably because the food source is so near the hive opening. Use some other type of feeder during nectar dearths.
- Small or weak hives are particularly vulnerable. Consider combining such hives before a nectar dearth.
- Commercial robbing screens are highly effective devices that allow the resident bees to get in and out while discouraging the robbers. These can be especially valuable for use on weaker hives that you do not want to combine.
What can I do to stop it?
Once it starts, stopping a robbing frenzy is not easy.
- Smoking will not stop robbing, but it will give you a reprieve while you close up the hive. Get the smoker going and set it next to the hive while you work.
- Reduce entrances to a very small opening. Some beekeepers stuff grass in the entrance—a technique that keeps out the robbers but allows some airflow.
- If robbing is really intense, you can simply close up the hive opening with hardware cloth or screen in a size the bees cannot get through (#8 or #10 work well). Close up the hive completely for several days until the robbers give up. If necessary, be sure to provide feed, pollen, water, and ventilation for the confined colony.
- A water-saturated towel thrown over the hive confuses the robbers but allows the hive residents to come and go from underneath the towel. Evaporation from the towel keeps the hive cool.
- Install a robbing screen. This device re-routes the hive residents through an alternative entrance while the robbing bees, following the scent from the hive, continue to butt into the screen.
- Some beekeepers spread a commercial product such as Vicks Vaporub at the entrance to the colony. This product contains strong-smelling compounds such as camphor, eucalyptus oil, and menthol that mask the hive odor and confuse the robber bees.
- Some beekeepers recommend removing the lids from all the hives in the apiary. The theory is that the bees become so busy defending their own hives that they stop robbing other hives. However, if the robber bees are coming from somewhere other than your own apiary, it won’t work. Also, it will do nothing to stop wasps and other predators from entering your hives at will. This is not a good strategy for an inexperienced beekeeper.