Melissa Bell of the University of Western Sydney – Hawkesbury is conducting Australia’s first-ever glasshouse experiments with blue banded bees. These trials, in collaboration with the Australian Native Bee Research Centre, are testing the potential of Australian native blue banded bees (Amegilla) as pollinators of glasshouse tomatoes.

Tomato crops grown inside glasshouses need a special kind of pollination to maximise their production. The flowers must be vibrated to release the pollen which is held inside tiny capsules in the flower. In Australia this process is currently done manually with mechanical vibrators. However, in overseas countries European bumble bees (Bombus) are often used to do this job.

Australia has no native species of bumble bees, and horticulturalists are applying to introduce European bumble bees to mainland Australia for crop pollination. Conservationists, however, are most concerned about the impact such an introduction would have on our Australian environment (see Aussie Bee Bulletin Issue 13). Could an Australian native bee be used instead to pollinate glasshouse tomatoes? Melissa Bell’s experiments are showing that this may indeed be possible.


Early Success in the Glasshouse

The earliest stages of this pioneering experiment were described in Issue 17 of Aussie Bee Bulletin. Blue banded bees were successfully introduced into a University glasshouse room (5.25 m long x 3 m wide x 4.3 m high) in late March, 2001. The bees rapidly accepted the confined space and began feeding on flowers and honey feeders that we had provided.

Les Dollin of the Australian Native Bee Research Centre made 55 nest blocks for the bees. These were Besser bricks, each filled with a soft clay mixture. Soon the bees began visiting these blocks too, digging nesting holes and bringing in supplies of pollen.

Blue Banded Bees Don’t Fly During Winter

In April and May, at the natural nest sites (outside of the glasshouse) all the adult bees die as the cold weather starts. In the nest burrows, though, immature bees (called prepupae) are curled up inside their sealed cells. These prepupae become dormant during winter and stay inside their cells until the weather warms up in spring. Then they complete their development into adults and emerge into the sunshine to begin the new flying season. So from about May to October no adult blue banded bees can be found flying in the garden.


So How Can We Pollinate Crops in Winter?

The biggest challenge with pollinating glasshouse tomato crops is that they flower all year round. If we want to use blue banded bees to pollinate these crops we will need to be able to supply flying adult bees during the cold months when the bees are normally dormant. Melissa wondered if she could make some of the blue banded bee prepupae develop into adults much earlier than usual by keeping them at warmer temperatures.