Wednesday 13 January 2021

Southern Emerald Damselfly (Lestes barbarus) Exuviae

I am very fortunate that the nationally rare Southern Emerald Damselfly can be seen in Kent at a couple of sites but in quite low numbers at present. Trying to find their exuviae then as you can imagine is hard to say the least but luckily last year, I acquired 2 Southern Emerald Damselfly exuviae for my collection from former Kent Dragonfly recorder, Gill Brook. With quiet times here now for a few months, I finally got round to photographing them a few days ago in the warmth of the conservatory. They are very similar in size and shape to the other Emeralds but there are a few identification features which I have tried to capture with the camera. The racket shaped mask is similar in shape to the Emerald (sponsa) and Scarce Emerald (dryas) whereas the Willow Emerald Damselfly has a more Aeshnid shaped mask. The caudal lamellae  have two distinct dark bands, with the distal end forming a point. A point that is also shared by the Scarce Emerald Damselfly. The Emerald Damselfly on the other hand has three distinct dark bands and the Willow Emerald Damselfly, 2 dark bands with sometimes a paler third band. Whilst the males in the field can be quite hard to identify from the Scarce Emerald Damselfly, the use of a microscope reveals the Southern Emerald Damselfly has longer finer hairs on segments seven to nine compared to the shorter hairs of the Scarce Emerald Damselfly. The females thankfully are a little easier with the ovipositor reaching just beyond the tenth segment whereas the Scarce Emerald ovipositor reaches well beyond segment ten. As I have found out through observations, at first it's quite hard to learn all these features but with constant revision, reading and looking back over specimens, The information does slowly go in. It's certainly keeping me quite busy in these times where we can not really leave the house and hopefully all this practice will pay off in the spring and summer when hopefully, I can find a few exuviae of different species for myself. 

Southern Emerald Damselfly (Lestes barbarus) exuviae showing typical Emerald shape, racket shaped mask and pointed banded caudal lamellae


Southern Emerald Damselfly (Lestes barbarus) exuviae showing caudal lamellae with two dark bands and pointed tip

Southern Emerald Damselfly (Lestes barbarus) female exuviae showing the ovipositor 
reaching just past the tenth segment

Southern Emerald Damselfly (Lestes barbarus) exuviae the long thin racket shaped mask


Southern Emerald Damselfly (Lestes barbarus) exuviae showing the long thin racket shaped mask

Southern Emerald Damselfly (Lestes barbarus) exuviae - male (left) female (right)

4 comments:

  1. Very interesting Marc but I think I will stick to larger creatures or get myself more powerful glasses. The pictures are brilliant at least I can see what you are talking about. Take care and stay safe.
    Mike.

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    1. Many thanks Mike. It's quite intricate work as you can imagine but nice to be able to educate myself and hopefully others with some of the id features on this rare species. Take care.

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  2. Excellent photography and information, Marc, but I fear that I'll never be in a situation to use the information as I suspect that this is a species that I'll never have the pleasure of encountering!

    Take great care and stay safe - - - Richard

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    1. Many thanks Richard. You never know, a trip to Kent at some point when we can all get out may yield a reward or two. It's certainly helping me out in these testing times and keeping me mentally sane and busy. Take care.

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