Bees – do they need to be actively managed during vegetation clearing

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European Honey Bees were introduced into Australia 190 years ago, but their wide distribution has mostly occurred in the last 80 years. As we all know, honey bees are cultivated by apiarists for the commercial production of honey but they are also important in pollinating plants. However, bees that have escaped from apiarists hives have now colonised many parts of Australia, including semi-arid eucalypt woodlands, rainforests and coastal heaths. These feral bees can be a particular nuisance during the spring and summer months in residential areas when they collect water to cool their hive. These bees can also become aggressive if disturbed.

Feral European Honey Bees occupy tree hollows that could be used as nesting sites for our three species of Black-Cockatoo, as diurnal retreats for Brushtail Possums and a diverse range of other arboreal mammals and tree hollow nesting birds. Feral honey bees may also reduce the populations of native pollinators and may adversely impact on bird pollinators (Oldroyd et al. 1997).

In the right conditions, feral honey bees can reach high densities. Oldroyd et al. (1994) reported 77.1 feral bee colonies/km2 in the riparian woodland of Wyperfold National Park in north-west Victoria and we recently had 22 bee hives removed from 13ha of bushland in Mandurah before vegetation clearing for a new subdivision.

Disturbing a European Honey Bee (Apis mellifera) hive during vegetation clearing can have serious consequences if done poorly. Feral European Honey Bees will routinely colonise hollows in tuarts, jarrahs and marri trees on the Swan Coastal Plain and if a tree with an active hive is disturbed or felled during a vegetation clearing program, then you are likely to have an angry and aggressive swarm of bees looking for revenge. Angry bees are often seen for up to 50m from where they were disturbed but can move much further in large swams.

We have watched as a poorly prepared pest exterminator sprayed a large hive of bees in a tree hollow after the tree was lowered to the ground. The hive was substantially larger than first thought and multiple bees strung the exterminator which required a quick trip and an overnight stay in the emergency department of the local hospital.

Large hives can be located deep in a tree trunk or fill a large hollow in a branch. A midday inspection might indicate only a few bees moving in and out the entrance, but once disturbed a large number of bees will emerge from the hive.

We recommend that professional advice from someone experienced in dealing with feral bees is engaged before trees are cleared, particularly if they are near to housing or built up areas. The bee extermination professionals will search the area using thermal imaging sensors and can detect hives that aren’t obvious to an untrained eye. Typically, hives that can be reached using a pole and treated from ground level with a low pressure powder spray unit but sometimes a cherry picker is deployed enabling the exterminators to get close enough to the entrance to partially destroy the honeycomb and then spray the occupants.

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References

Oldroyd, B. P., S. H. Lawler, and R. H. Crozier. 1994. Do feral honey bees (Apis mellifera) and regent parrots (Polytelis anthopeplus) compete for nest sites? Australian Journal of Ecology 19:70-76.

Oldroyd, B. P., E. G. Thexton, S. H. Lawler, and R. H. Crozier. 1997. Population demography of Australian feral Bees (Apis mellifera). Oecologia 111:381-387.

Photo credit: Top – nest box that has been overtaken by feral bees; bottom – nest boxes being removed or treated due to infestation by feral bees

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