[Odonata-l] Fwd: Ophiogomphus head damage

[Dennis Paulson]

Begin forwarded message:

> From: "Nick and Ailsa Donnelly" <tdonelly at binghamton.edu>
> Date: March 21, 2008 2:09:18 PM PDT
> To: <dennispaulson at comcast.net>
> Subject: To be posted on the list serve
>
>
> Damage to rear of female heads of Ophiogomphus.
>
> Recently I have been removing the heads of several species of  
> Ophiogomphus
> to examine the rear.  I have noticed some damage, which I can best  
> describe
> as crude near-vertical elongate indentations, usually with small  
> scrape
> marks.  I first thought these were something I was doing while  
> removing the
> heads, but I now think that they are older, and probably existed  
> during the
> life of the female.  Perhaps the pressure of the cerci (which lie  
> on th
> erear of the head) is more important than I had thought in  
> maintaining the
> grab of the close-fitting eprproct on the face.  Has anyone ese  
> wondered
> about these marks?
>
> It seems pretty clear that tandem pairing removes most of the hairs  
> on the
> female occiput by rubbing (teneral females are quite hirsute, but  
> older
> females have few hairs left), and I believe the horns on the  
> occiput are
> often broken right off.  But these marks on the rear of the head  
> baffle me,
> unless they are the marks left by  the medial edge of the cercus.
>
> Nick Donnelly




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