Thursday, August 6, 2015

Which Damsel ? - My Distress

This damselfly showed up on a branch just off of our deck.  I enjoy the challenge of identifying insects but a long visit to OdonataCentral and other sites convinced me that I was out of my depth.  I sent it to fellow amateur naturalist Jon Rapp of Columbia who responded in an hour with my answer.

Jon pointed out that it is difficult to identify because females are hard to understand.  Yeah Jon, tell me about understanding females!  Actually to use his words:
"Now then, the first two aren't as easy because they are female. Some guides don't even bother to show female damsels. They tell you that your best bet is to find the nearby males and ID those because so many females look alike. Given that, I think I can ID this one as a female Dusky Dancer - Argia translata. Females of this species are very similar to female Powdered Dancers. However, your view shows the striping on the segments S8-10 which Dusky's have and Powdered don't. So I think you're safe with this ID. (But keep in mind I am no expert!)."
Few people would claim to be an "Odonate expert" but the fact is that much of what we know about frequency and distribution of Odes (dragonflies and damselflies) and insects in general depends upon a core of "citizen scientists" who find and study a class of insects or other animals and diligently report their findings to scientific databases such as OdonataCentral and BAMONA.

With modern pocket cameras or even cell phones it is possible to get good insect photographs.  An example from this online key requires an examination of the hairs on the legs. "Are the spines on the 2nd joint of the legs twice as long as the spaces between the spines? Then your damselfly is a Dancer belonging to the genus Argia." By adjusting the camera angle in another photograph to get a better background and cropping to enlarge the legs, you can make the call - it is a Dancer.

Identification of insects to the species level often depends on identifying small differences in body parts that otherwise would escape notice.  An example is Jon's statement "striping on the segments S8-10" as seen above to separate a Dusky from a Powdered Damselfly.

I would encourage you to try finding your own answer using field guides and online resources.  You may find your inner naturalist.  We have listed some sources in the "Resources" link found at the top of the right hand column above.  WARNING- IT CAN BECOME ADDICTIVE!

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