[Odonata-l] Apparent strongly andromorphic female Eastern Forktail

[Nick and Ailsa Donnelly]

Andromorphs of this species are well known but are rarely found.  Possibly
the best way to find them is to see what looks like a male but which
exhibits female behavior. (Like flying around in the grass away from the
water when all the males are doing their territorial thing at water's edge.)
In some species of Ischnura the andromorph and gynomorph females are nearly
equally numerous, but verticalis is one with rare andromorph females.  (Some
species have no andromorph females.)  There has been some study on the
phenomenon but no total agreement on what is happening.  What is undisputed
is that the behavior of the two morphs is very different, and andromorph
females don't get disturbed my males while they ae ovipositing. 

Nick Donnelly 

-----Original Message-----
From: odonata-l-bounces at listhost.ups.edu
[mailto:odonata-l-bounces at listhost.ups.edu] On Behalf Of Julie A. Craves
Sent: Sunday, July 29, 2007 10:27 AM
To: odonata-l at listhost.ups.edu
Subject: [Odonata-l] Apparent strongly andromorphic female Eastern Forktail

Yesterday while doing an Odonata survey at the Detroit River International
Wildlife Refuge Humbug Marsh Unit (adjacent to Detroit River), Wayne Co.,
Trenton, MI, I collected an unusual female damselfly.

Vulvar spine and what I can "read" of the prothorax and mesostigmal plates
under my microscope indicate this is Ischnura verticalis, Eastern Forktail.
However, I've never seen an illustration of one so strongly male-like
(bright lime green and black) and the bright blue pattern on the dorsal
abdomen tip is unlike any I've seen -- on any forktail.

I have posted four photos at
http://urbanodephotos.blogspot.com/2007/07/andromorphic-ischnura-verticalis.
html
(http://tinyurl.com/2ouyrz).  I'd appreciate any feedback on this insect.

-- 
Julie A. Craves					
Rouge River Bird Observatory
University of Michigan-Dearborn

http://www.rrbo.org
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