A bumble bee investigates millkweed for pollen.

Credit: Roger Chalkley

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SYDNEY: Native Australian bees may stop the introduction of a new exotic species to the mainland, perhaps averting yet another ecological disaster like the cane toads or the European carp.

Greenhouse tomato growers want to import bumble bees (Bombus terrestris) to Australia to pollinate their crops, but according to a Sydney scientist, the fuzzy Europeans may be redundant as native bees may be up to the task.

As with other introductions gone wrong, imported bumble bees have already escaped into the wild in Tasmania, and studies there suggest they can out-compete native species for food and nest sites. According to Mark Greco, of the University of Western Sydney's Centre for Plant and Food Science, introducing them to mainland Australia would run the risk of driving native stingless social bees (Trigona carbonaria) to extinction.

"Why risk introducing another exotic species when a native one could do a similar or even better job," asked Greco.

If exotic bumble bees did escape into the wild in mainland Australia, they would endanger not only native bee populations, but the rest of the environment as well. Because bumbles are more familiar with foreign flowers than native ones, "they might help the spread of exotic weeds already present in Australia," said Greco.

Pollinated flowers yield bigger, heavier, better shaped fruits than those that remain unpollinated, according to Greco. Historically, greenhouse crops have been pollinated via 'mechanical vibration' - literally shaking the flowers with an electric vibrating wand to move pollen from the male parts of the flower to the female part - a labour intensive and expensive process. In the last two years, however, greenhouse farmers overseas have begun using bumble bees to pollinate their crops because they 'buzz pollinate'.

"The bees grab the flower with their legs and buzz their wings, shaking pollen from the male parts to the female parts" said Greco. Some of the pollen also lands on the bees, who then fly off and feed it to their young. Using bees in greenhouses means getting all the advantages of pollinated crops, but without the high cost of mechanical methods. Saving on costs while still producing high quality fruit has Australian tomato growers abuzz over bumbles.

Research at the university shows the native bees do just as good a job with tomatoes as do bumbles, and that their pollination prowess extends into a wide variety of other food crops, and may even be enough to launch these stingless bees into outer space. Because of their abilities, and the fact that they can't sting their astronaut keepers, "stingless native bees are being considered for pollinators for greenhouses in space ... and on the Moon and Mars," said Greco.

In the ultimate turnaround, native bees may not only keep bumbles out of Australia, but also beat them to rest of the Solar System.

In order for native bees to become a viable alternative to bumbles, Australia would need lots of colonies and new management regimes, but according to Greco, full development of a native bee alternative could be only 12 to 18 months away, making bumble bee imports unnecessary.

The Australian federal government, which regulates the introduction of new species, has yet to rule on the matter. According to a spokesperson for the Department for Environment and Heritage in Canberra, the Australian Greenhouse & Hydroponic Association - the organisation representing the tomato growers - is investigating the potential risks of bumbles.

Authorities will base a decision on their report, as well as on "the views of relevant state and territory ministers, experts, stakeholders, and analysis and advice provided by his department." A decision by the Minister for Environment and Heritage, Ian Campbell, is not expected soon.