Function of the legs in Odonata
Mon, 31 Jan 2000 13:03:23 -0800
Odonata - http://www.listbot.com/cgi-bin/subscriber
Tim Manolis wrote me:
>A thought on Bob Behrstock's theories on leg spines and foraging -- if leg
>spines affect perching ability, then possible relationships between spine
>length and hunting from perches vs. constant aerial foraging might be
>affected by the perch rather than the prey.
I'm forwarding this message, as I thought everyone on the list should have
the benefit of Tim's thinking. There might even be some predictions
possible about leg spines vs. perching type. I recently took a photo of an
Erythemis vesiculosa (Great Pondhawk) in Florida that shows the two hind
tibiae squeezing the branch from either side well above the tarsal claws.
This indicates that there are diverse perching options, and perhaps any
kind of spines work for perching; still, this should be examined.
(Parenthetically, this dragonfly perched with 4 legs, something I hadn't
noted in the genus before). The leg spines are probably very versatile for
perching, and someone could actually examine scads of photos of different
species perching (making sure that they weren't posed) and come up with a
nice description of how they do it. It's never been done, to my knowledge,
and we only touched on it last year with discussions of 4 legs vs. 6. The
next project would be looking at videos of dragonflies landing and taking
off, to see how the legs were used in both stages (which might well have an
effect on how they are held during perching).
I could easily see a master's thesis on dragonfly perching!
Dennis Paulson, Director phone 253-756-3798
Slater Museum of Natural History fax 253-756-3352
University of Puget Sound e-mail email@example.com
Tacoma, WA 98416
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