In the latest issue of the journal Austral Ecology is an article (link is to abstract) about the invasion of the large earth bumblebee (Bombus terrestris) into Tasmania and nearby mainland Australia. This species is one among several non-native bees in that region competing with native bees for food. Conflicts arise because at the same time, they are valued by farmers and others who depend on pollinators for economic reasons. Click here to see a pdf file with a brief history of bumblebee introduction in Australia (and a nice identification guide).
Update 5/26/04: Thanks to Jenny L. for sending a link to this interesting article that speculates about exotic bumblebee impact in Australia. The Aussie Bee website is definitely the place to go when you need info about any bee sighted in Australia.