[Odonata-l] Fwd: Chromagrion mating - photos needed

[Dennis Paulson]

Nick Donnelly is having trouble posting to Odonata-l, so he asked me  
to send this for him.

Begin forwarded message:

> From: "Nick and Ailsa Donnelly" <tdonelly at binghamton.edu>
> Date: May 29, 2008 6:46:11 PM PDT
> To: Cc: <dennispaulson at comcast.net>
> Subject: Chromagrion mating - photos needed
>
> Perhaps the strangest tandem apparatus I have found in North American
> damselflies appears to be that of the Aurora Damsel - Chromagrion  
> conditum.
> We need close-up photos of tandem pairs to figure out how the  
> various pieces
> fit together.  I am preparing illustrations for an Argia article,  
> but the
> article might not appear until the mating season is over for this  
> year, and
> I am hoping that one of the many keen photographers can get some  
> images
> before that.
>
> The male terminal appendages are not obviously odd, until one  
> notices that
> the inferiors (paraproct) have spoon-like dorsal scoops in the  
> distal half.
> The superiors (cerci) have a subbasal flattened spine with a strong  
> hook at
> the end.  This seems to have no equivalent in North American  
> damselflies.  I
> am concerned with where these hooks might engage the female  
> prothorax. (The
> mesostigmal laminae are rather ordinary and do not seem to present an
> opportunity for these hooks.)
>
> The female prothorax is the most modified I have seen in North  
> American
> damselflies.  The hind lobe is large and bent so far forward that  
> one does
> not immediately recognize it for what it is.  It has prominent  
> dorsal knobs
> that seem dimensionally suitable to engage the scoops of the male
> paraprocts.
>
> But what of the hooked accessory inner sub-basal spine of the male  
> cerci?
> These fit somewhere, but where?  I am guessing on the female  
> prothoracic
> hind lobe, but it is difficult to see at this time what the tandem  
> mechanism
> might be.
>
> So, if you are into ultra close-up photos (and I know that some of  
> you are),
> and you are in the northeastern part of the US, please try to  
> photograph
> tandem pairs of this species!




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