Dluogs's picture

Damselfy needing ID correction - probably Azure

Observed: 3rd June 2011 By: DluogsDluogs’s reputation in InvertebratesDluogs’s reputation in InvertebratesDluogs’s reputation in Invertebrates
Variable Damselfly S2
Variable Damselfly S2 1
Variable Damselfly S2 1 2
Variable Damselfly S2 1 2 3
Variable Damselfly S2 1 2 3 4

The marks on the second and ninth abdomenal segments made me and others think this was a Variable Damselfly, until someone pointed out the pronotum structure is wrong for this species. I have been convinced it's an Azure Damselfly.

Species interactions

No interactions present.


RoyW's picture

An interesting specimen.

Although the S2 (second abdomenal segment) marking seems to identify this as a Variable Damselfly, and the S9 marking also seems to fit well with this ID, the truth is that these markings can be variable in most Coenagrion species (especially the markings on S9, which are certainly not something to rely on for an ID - very similar markings can often be seen on Azure Damselflies).

A summary of the features on this individual:
S2 marking - U-shaped marking joined to the black ring at the rear of the segment (the typical marking of pulchellum; puella typically has the U-marking separate from the black ring - but this mark can vary in most Coenagrion species).
S9 marking - perhaps most similar to the more typical marking of pulchellum, but the marking is variable on both species and very similar markings are often seem on puella
antehumeral stripes - Unbroken, which is typical for puella; pulchellum more often than not has broken antehumeral stripes, but it is not uncommon for them to be unbroken and identical to this individual.
bar between post occular spots - typically absent in puella (as seen here), almost always present in pulchellum.
rear edge of pronotum - A diagnostic feature which is more reliable than all others (except perhaps abdominal appendages). The rear edge of the pronotum should be deeply indented in pulchellum, but is more gently curved - as in the subject photos - in puella. See this link: http://www.habitas.org.uk/dragonflyireland/femaleblues.htm
abdomenal appendages - Unfortunately not clear in the photo.

So, in my opinion, there is more to suggest that this is an abnormal puella (Azure Damselfly), than there is to suggest that it is pulchellum (Variable Damselfly) - including the shape of the pronotum, which is the most important feature which can clearly be seen in the photos.

(Of course, there is always the theoretical possibility that this, and other odd damselflies that seem to show characteristics of more than one species, could be hybrids).

Dluogs's picture

Thank you!

I'm glad you find it interesting! Thank you very much for the detailed response. It's the thing that has really impressed me about this site - people are very generous in helping others learn from their wisdom.

I had noticed the lack of break in the ante-humeral stripes but I am too much of a novice to be able to really see what shape the rear edge of the pronotum is, though I had been trying to look.

I've found a couple more photos of what is almost certainly the same specimen which I've uploaded in case they shed any further light on its ID. They all have a distinctive narrow dark blob blue part on the top of the of what is probably S5, so I think it's the same one. It came and went so I couldn't be completely sure.

If it is the same animal, and I think it is, that would mean that I have yet to see a Variable Damselfly. If I were less of a novice, I'd be very pleased to have found an unusual Azure one, but at this stage, I would have preferred to have correctly identified a species new to me. Azures are common here - or they were in 2010. I only saw one or two this year, but then I wasn't free to look on so many suitable days.

I've changed the title and see if it attracts any more interest so that the correct ID is accepted. If no one else comments, then I will accept your judgement and change it to Azure Damselfy.

Thank you again!


RoyW's picture

Still Azure for me.

These additional photos convince me even more that this is an odd Azure Damselfly - though there is some disagreement at the moment!

You could try posting the photos on UKdragonflies for some other opinions (.co.uk I think), or if you like I could start a thread there with a link to this observation, and then post a link here so you know where to find it.

Edit: forgot to say, the pronotum is the bit between the head and thorax.

RoyW's picture

Reasons why this is a Variable?

Would any of those who have agreed with the initial ID of Variable Damselfly (which has 3 agreements at present) be prepared to say why they think that this is the correct ID?

Dluogs's picture

You've convinced me...

You've convinced me - it seems pretty clear to me that body structure wins over surface markings which seem to be pretty variable for several members of this genus.

As for my photos, please feel free to use them however you wish. If they would be useful on the dragonfly site as a case study, do post them. But I am happy to accept this as an a-typical Azure Damselfly. Perhaps I'll meet a true Variable Damselfly another year.

RoyW's picture


Thanks for the permission to post your photos.
I have attached two of them to this thread ( http://www.ukdragonflies.com/index.php?topic=2021.msg11369#new ).
Initially I expect that there may be posts that identify these photos as a Variable, but I expect this to be challenged when some of the more experienced members look at it closely - two of them are based in Hampshire and I have seen web postings from both saying that they have not seen the species in the county but are actively searching - which is why I mentioned that the photos were taken in Hampshire in the post! ;o)

Nb: If you are not registered with the UKDragonflies website, and signed in when you view the thread, you will be able to see the posts but not the attached photos.