In a message dated 3/7/00 2:46:15 AM, [log in to unmask] writes:

<<What has Australian imports got to do with this?  >>

Nothing. Perhaps I stated my case too strongly. My apologies for baiting you.
I'm upset about this issue and spoiling for an argument.

<<We have cases now of leaf cutter bees being imported to Australia for
lucerne pollination and I am told that some of our native wasps are
parasitising them.>>

Thank you, that's new information to me.

<<What happens when some native pollinators are forced into a small area?
Does one outcompete the other?>>

  The greatest threat to native pollinators is habitat loss. Take, for
example, here in North America, the migration of pollinators along a
"pollination corridor" between Mexico and the US. I recently posted a long
quote from an article about a Colorado study that showed climate change
having a deleterious effect on animals (2/16, Animal Starvation and the
Weather). The study looked at how warm springs with deeper snowpacks cause
animals to come out of hibernation too soon before vegetation appears, with
starvation being the result.
   The article said researcher David Inouye's next study will look at how
these changes affect hummingbirds that migrate long distances from Mexico to
the US. Pollinators that migrate rely on a "pollination corridor" with a
carefully timed sequence of appearance of flowers needing pollination. The
results are not in and the study has not been done, but If that timing is
thrown off by widening variations between low and high altitude habitats,
then the situation for native pollinators can only worsen.
   Essentially, it's another way native pollinators are losing habitat, this
time brought on by climatic change. Habitat loss is a significant threat to
native pollinators. So are pesticides. Competition from honey bees, if any,
is not.
John Mitchell