As a producer of bumble bees, I will be perceived as tending to portray the positive aspects of the introduction of bumble bees to the mainland. However I also come here as an insect ecologist and do feel that the cautionary comments made at this meeting by the "environmental" side, particularly concerning seed production by weeds, should not be dismissed out of hand.

Bumble bees are reared in indoor controlled-environment facilities and have no interaction with "nature" until point of sale to greenhouse vegetable growers. Wherever bumble bees have become available for greenhouse tomato pollination the uptake by growers has been extremely rapid and always seems to put a strain on supply in new markets. This is due to their extreme cost effectiveness whereby each dollar spent on bumble bees can translate to ten dollars of EXTRA tomato production (even in comparison with hand pollination at a similar or greater cost) and where the cost of the bees is approximately 1% of the value of the crop.

Another environmental issue is that bumble bee use forces a reduction in the use of wide spectrum insecticides.

The escape of bumble bees into the natural environment is probably inevitable but because of the lack of success of previous deliberate introductions I suspect they may have difficulty maintaining a population in mainland Australia. On the other hand, they are doing well in Tasmania, so if my suspicion was to be correct there must be some limiting factor (possibly a ground dwelling or aerial predator) which is absent from Tasmania.

A feature of bumble bee biology that is likely to limit their niche competition with Australia's native solitary bees is that the bumble bee colony cycle covers several months and populations will be limited by nectar and/or pollen shortage at any stage of the season. So, it can be concluded that unless food availability exactly tracks bumble bee colony growth (most unlikely to be correlated) most of the time the food availability will exist in surplus to the bumble bees' requirements.