Dave Haas wrote:>
> This situatuation seems to suggest a positive feed back loop where
> long proboscises select for long corollas and long corollas for long
> proboscises. I can see how long proboscised flies would have an
> advantage over short proboscised flies by being able to obtain more
> nectar and thus more offspring but what about the flowers? Why would
> longer corollas be selected for? Is it exclusively the hover flies doing the
> selecting or is it possibly other pollinators which are able to remove nectar
> without pollinating the smaller corollaed flowers? Any thoughts?
> This is the only explanation I have heard to keep increasing the length
of the corolla. Perhaps others can suggest other reasons.
Janice
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Janice M. Glime, Professor
Department of Biological Sciences
Michigan Technological University
Houghton, MI 49931-1295
jmglime at mtu.edu
906-487-2546
FAX 906-487-3167
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