Roe Valley Beekeepers Association
Robbing can be considered under the following four headings:
1. Causes of Robbing are often avoidable
2. Prevention of robbing is easier than cure
3. Early recognition of the signs of robbing is essential
4. Management of robbing should be decisive.
Robbing occurs when colonies are maintained in close proximity, when beekeepers carelessly spill sugar or honey in the apiary, when a nectar flow suddenly ceases and when in times of dearth colonies are opened for unnecessarily long periods. Nucs and small colonies are at particular risk if placed in close proximity to stronger ones and when entrances are left open. Some bee types (eg Italian Yellow ) are more likely to rob othan others. Robbing generally occurs within apiaries but can also occur between apiaries, and can be performed by other insects, particularly wasps. Beekeepers may inadvertently initiate robbing by feeding during daylight hours, and when selectively feeding only some colonies within the apiary. Bees only rob honey, not oother stored colony products. A colony which looses its queen is more likely to be robbed, and a hive which perishes in winter will be robbed in early spring by hungry neighbours
Care in beekeeping activities can minimise the possibility of robbing. Avoid situations where drifting can occur by careful positioning of hives. Keep entrance blocks in place when nectar flow is reduced and always on nucs. Ensure that there are no other access routes into the hive. When working, avoid spillage of sugar or honey, and minimise the time hives are opened. Open weak colonies before stronger ones to avoid being followed to vulnerable small hives by robber bees. Feed at dusk so that the excited agitated flying which can occur when bees are fed is minimised. All colonies should be fed together and beekeepers should be alert to the early warning signs of robbers entering hives which are being manipulated.
There are two possible versions of robbing to be considered.
Silent robbing can occur insidiously and the robbed bees appear to accept the robbers without signs of agitation or defence. Robber bees fly directly into the robbed hive and will be observed to fly between hives. When a bee leaves a hive it has robbed its ventriculus will be full and this will result in an imbalance causing it to fly head down with rear legs forward. An empty bee leaving its hive flies with rear legs extended and in a more head up posture.
When robbing occurs from a hive which has pewrished the bees will be seen entering the hive but will not be bringing pollen inwards.
When robbing involves defence, guard bees will intercept robbers on the landing board ‘roughing up’ those which are not passive and submissive and which do not have their own brood smell. Robbers will attempt to avoid guards by approaching the hive in a zig zag flight pattern.
Prevention is more effective than cure and when robbing begins it can be difficult to stop. At the first signs of robbing entrances should be closed to a single beeway if possible to provide easier guarding conditions. Entrances can be disguised with plugs of dried grass or a sheet of glass placed in front of the landing board to confuse robber bees more than the hives inhabitants which will exit the sides. Robber hives may have to be relocated a good distance from the apiary but if this is not possible an alternative approach is to swap the robber and robbed hives positions in the apiary to cause confusion. There is little point in moving robbed colonies as they are likely to have been chemically marked, and will continue to be a target. If the robbed colony is to be moved the beekeeper should set up a hive on the original robbed site containing a frame or two of stores so that the robbers finish their work and are more likely to leave the robbed hive alone.