Dear Plant-eders,
The other day I showed my botany class part of the Private Life of
Plants video on flowers and pollinators. There was a part
where a hover fly with an extremely long proboscis was visiting
flowers with extremely long corollas. I explained how this was an
example of co-evolution where the population of hover flies through
natural selection evoleved long proboscises to reach the nectar
and the flowers long corollas accomodate the insect.
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?
Dave Haas
