Wednesday, 14 April 2021

Dainty Detective

I spent a few hours at Sandwich Bay this morning where after meeting Steffan (the warden) at 9am, we made our way to the Dainty pool where I spent about 15 minutes collecting a few larvae which we hoped would be Dainty Damselfly nymphs. I had brought my tank set up with me and after sitting down and going through the nymphs looking for the key features of Dainty, I spent some time setting up. Having never seen Dainty Damselfly nymphs before and hardly any literature out there about identifying them, (what there is in often in a foreign language), I spent some more time with Steffan going through the various species that they could be confused with. I still have much to learn myself about identifying some of the species at this stage but a few nymphs were found with spotting behind the eyes. This ruled out Dainty straight away as these were likely Azure or Variable Damselfly nymphs which have spotting. A careful count of the antennae on some of them revealed 7 segments which through elimination, ruled out Common Blue which generally have 6 segments. This left us with Blue tailed Damselfly nymph which also has 7 segments. It was then left to look at the caudal lamellae which in Blue tailed Damselfly nymphs, are long, thin and tapered towards the tip. The setae on one side reach the mid point and the other side, about a third. A few nymphs I think were of this species but a couple had very broad caudal lamellae which in Dainty are more broad in the distal half and ending in a point. The setae on one side reaches the mid point and the other side, over a third in length. With all these factors in mind, I photographed one of the likely candidates which showed the 7 antennae, lack of spotting on the head and broad rounded caudal lamellae. The only slight nagging point is are the setae slightly wrong? Looking at other photos on the internet vary in size and these fit within the range I have seen. There is still much to be written and learnt  about these nymphs and hopefully these photos might help out at some point with a discussion on the id features. Whether it or isn't a Dainty Damselfly nymph, it was an educational few hours where hopefully I can return soon to maybe look for some more nymphs before the real fun begins when the adults emerge in a month or so. 

'Hopeful' Dainty Damselfly Nymph

Saturday, 16 January 2021

Dainty Damselfly (Coenagrion scitulum) Exuviae Studies

With a bit of time on my hands at the moment as we are on a rota at work currently, I thought it would give me the chance to spend a few days examining the Dainty Damselfly exuviae I collected last year at Sandwich Bay. A look through the books I have provided very little information as did the internet surprisingly and even then, a few sites of interest I did find were in languages I didn't understand. There were also few photos showing how to identify them which to someone like me, made the task quite difficult as I hope at some point later this year all being well, to hopefully gain permission to visit the site again to survey for nymphs and adults. With this seemingly lack of information out there about our rarest damselfly, this provided me with an opportunity to spend a few days in the warmth of the conservatory slowly investigating the various parts of the exuviae which make up the Dainty Damselfly. A shout out on Twitter for any help resulted in Dave Smallshire and Thomas Buchner providing me with some much needed help which I soon put into practice as I studied a number of exuviae to see the key features needed. As I got my eye in, the features became easier to see and comparing these to other 'blue' damselflies exuviae with which they look very similar, I was starting to have a better understanding at identifying the Dainty. With my knowledge at a satisfactory level now and feeling more confident, I started to take apart one of the exuviae to study it in closer detail. A few minutes soaking in some water and vinegar enabled me to prize apart the caudal lamellae and remove them whilst looking through the hand lens. This was followed by then carefully removing the mask which I can tell you, was very fiddly indeed. With the parts removed, this gave me the chance to study them better and see the proper shape of the caudal lamellae and mask. Each part was photographed individually and although I use a trusty Sigma 150mm macro lens, I really could have done with a 100mm macro lens for this work to achieve some closer and sharper images. Having said that, I ended up with some useful photos hopefully showing off some of the key identification features to identify the Dainty Damselfly exuviae which I know will definitely me and hopefully help others should they suspect they have found this species elsewhere in Kent. With some more time available next week, I may well chose a few more species exuviae and try this approach with them to show off their id features. 

Dainty Damselfly (Coenagrion scitulum) exuviae studies

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)

Tuesday, 5 January 2021

Golden Ringed Dragonfly (Cordulegaster boltonii) Exuviae

Having collected dragonfly and damselfly exuviae for the past 5 years or so, I have wanted to get my hands on what has to be the most impressive set of teeth on an exuviae, the Golden ringed Dragonfly. Although this species is present in small numbers in West Kent, the chances of me finding an exuviae of this species are quite low although I must say, I haven't personally looked for them. Luckily for me, during a conversation last May with Gill Brook (former Kent Dragonfly Recorder), we got onto the talking about exuviae and I mentioned that I needed Golden Ringed Dragonfly for my collection. The next time we met a few weeks later, Gill brought along a number of different species exuviae that I needed including 2 Golden ringed Dragonfly exuviae. They were just as impressive as I imagined and to actually study those jaws at close range was pretty good. This species is a sit and wait predator, laying in the mud and debris on the bottom of streams with just its eyes above the mud. Any passing prey getting close enough will probably not know much about the sudden attack which is about to happen. I can only imagine that when in those inter meshing teeth, escape is near impossible. This species also has I believe the longest time as a nymph where it can emerge any time from 2 -5 years depending on water temperature and location. Now that winter has arrived and no odonata are to be seen, I intend to pass some time either net dipping and photographing some nymphs and also photographing the new exuviae that I received last year. With this in mind, I spent and afternoon last weekend taking a number of photos of the Golden ringed Dragonfly exuviae from a number of angles to show off some of the identification features. Although the shape is quite diagnostic with bits of debris also sticking to the exuviae, the key feature unique to this species is those impressive teeth, which are quite unlike any other species. I would love to find one of these for myself at some point but i'm just very pleased now to have these in my collection. Hopefully over the next few weeks, I will get around to photographing a few more species which I shall share in due coarse. 

Golden Ringed Dragonfly (Cordulegaster boltonii) - female exuviae