[Odonata-l] New ?'s and possible observations of luminescence versus reflected ambient light in Calopteryx maculata album #2

[Martha Smith]

Since there has been some interest in the questions of luminescence versus
relected ambient light in the substance produced on the ventral posterior
section of the Cm's abdomen-at or near the anus-I took another look at my
albums on the site linked to here--AND I think I may have noticed something
new of possible interest:

http://marthasmith.neptune.com/?selectedalbum=marthasmith162309

The film is very dark with resolution problems--BUT, if you look at #2
CMRep.BehavVabc-either at 200%--or better-full screen-you can discern, not
only the "presentation" action, but luminescent/ambient-reflective property
of the expanding area of substance production.

The important *NEW* observation is that it appears that as the Cm is dipping
its posterior, ventral abdomen-anal area in the water, it appears to produce
its own "glow,"  underwater.  You have to look very carefully, stopping th
tape frame by frame if possible.  Would ambient reflected light in the
shadow of a damselfly on its posterior, ventral abdomen produce a
"glow-like," light under water?  Or could this be a case of luminescence?
Does the dipping over a period of time enhance this production--in
preparation for reproductive behavior?

So, here's a list of things to look for:

1.  At first,look at the quick somewhat jerky bending up of the abdomen to
show the, single line of reflective/luminescent(?) substance--It appears to
be three dots that flash in the reflecting sunlight as the anus area is
presented. album #3 has the frame time lengthened to separate and focus on
the action.

2.  The single line of three dots actually increases to at least a double
line of dots, toward the end of the week, on the expanding anal area -
almost a week after the single line was filmed--during this time, possibly,
the anal area either opens up (out), or simply increases in breadth in
preparation for reproductive behavior.

3.  The substance inceases in volume and, possibly,
reflectivity/or/luminescence--unless its, apparent, brightness is only due
to increase in volume and area of production.--This increase took almost a
week to achieve.

4.  The frames are all noted and filming took place over a week, approx.

5.  After the segment with the posterior, ventral anus presentation, it
shows the highly reflective nature of the face plate--but, most importantly,
in the dark -very dark shadows-you can see the Cm dragging/dipping its anus
in the water--it did this over a long period of time--and I have seen this
action before with Cms, and frankly, it doesn't actually appear at these
particular times that it is an act of oviposition.  It looks more like
preparing the anal area for the elasticity needed for copulation.

5a.  At this point, you need to stop the tape and go frame by frame, and
look VERY CLOSELY at the nature of the "glow" produced directly under the
water where the anus is placed--it "reflects(if that is what it is)"-or
luminesces if it is actually producing the light on its own due to enzymatic
activity-either totally insect produced or-a property enhanced by dipping
the anus into the H2O.--After doing that, start watching the tape, watching
the glowing nature of the light as opposed to the adjacent light reflecting
off the underwater debris and the bottom of the stream bed--I think I see a
difference in their respective properties--someone with better equipment,
might be able to give us  a better answer.  Yes, it could just be the sun
reflecting off of the substance---but, it almost seems to me the, the manner
of the way the light is produced could possiblly suggest-something more than
just reflection--Bioluminescence, Phosphorescence,
Fluorescenc-Luminescence---CAN ODONATES SEE THIS "GLOW" FROM THE TOPS OF
TALL TREES---OR, CRUISING STREAMS, ETC.?

Trust me, if you care to do this, the music does make the effort
palatable--and full screen is best--for just looking for the "glow"
property.

Thanks!

Martha Edwards Smith
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