[Odonata-l] Morphology and niche overlap

[Joshua Stuart Rose]

At 02:40 PM 3/26/2006, Dennis Paulson wrote:

>Niche theory has always predicted that there should be some 
>difference in two closely related species to allow them to coexist, 
>yet that doesn't seem to be the case in many odonate genera. Are 
>odonates examples of animals that can be used to refute the 
>absolutes of both niche theory and allopatric-speciation theory?

I do not think the data exist yet to allow us to make this claim. I 
tried to apply niche theory to odonates in my dissertation, and even 
restricting myself to a fairly narrow set of populations, the 
challenge was formidable. And I just worked on adults; to really work 
out the problem would require data on larvae as well. Maybe things 
have progressed a lot in the last year or two, but I did not see any 
ecological niche data on larva except at the coarsest scales: pH, 
plant/aquatic community, seasonal phenology.

I haven't read Mark McPeek's latest stuff - I'm out of academia now 
and so do not have ready access to a decent library - but I think 
short-term, fine-scale allopatry is still a much more likely method 
of speciation, especially for insects with relatively limited 
dispersal and specialized habitat, than simultaneous mutation of male 
and female lock-and-key structures in sympatry. There is relatively 
extensive evidence among birds, and I think Hawaiian Drosophila too, 
that species get much less picky about mates when mates are in very 
short supply; and it is very difficult to figure out patterns of 
sympatry/allopatry in the past.

Would love to hear if there have been some big new publications in 
the above areas that I've missed...

Cheers,

Josh

Joshua S. Rose, Ph.D.
http://www.duke.edu/~jsr6/
<mailto:opihi at mindspring.com>opihi at mindspring.com

Bird Program Specialist
<http://www.worldbirdingcenter.org/>World Birding Center
Bentsen-Rio Grande Valley State Park
<mailto:joshua.rose at tpwd.state.tx.us>joshua.rose at tpwd.state.tx.us
956-584-9156 x 236

Duke Natural History Society
http://www.biology.duke.edu/dnhs/