Tuesday, 6 November 2018

Brilliant Emerald v's Downy Emerald

Having collected both Brilliant Emerald and Downy Emerald exuviae this year which do look somewhat similar, I have recently photographed them separately to aid others in the identification of both species but thought it would be a good idea to make some plates of both species together to show some of the key features of the species. Until this year when personally, I was still learning the features of both species for the first time, I soon found out that there are some quite obvious features to look out for and once I had got my eye in, I was then able to quite easily distinguish both species quite easily. I suppose the key features on the Brilliant Emerald exuviae are the prominent dorsal spine on S9 and dark spots on the abdomen whereas the Downy Emerald exuviae can be identified by the small or absent dorsal spine on S9 and the two dark stripes on the side of the thorax. I'm sure throughout the winter period that I will spend some more time studying and photographing exuviae but I hope enthusiasts find the plates of these two species of use to them in the near future.


Sunday, 4 November 2018

Nearing Willow End

It seems to be more difficult in the past few weeks to have weekends where the weather is sunny and warm enough for what dragonflies and damselflies there are left to fly. Yesterday (Saturday) the weather was quite sunny and with twelve degrees celsius forecast, I decided that I would spend a couple of hours at Nethergong hoping to find a few late Willow Emerald Damselflies. On arrival around midday, it was indeed sunny but with a very brisk wind blowing, it was going to be hard work trying to find anything. I spent some time looking in some of the sunny sheltered areas and was pleased to find 11 Common Darter still on the wing but after an initial look in areas for Willow Emerald Damselfly which drew a blank, I had another walk around and thankfully, I managed to find 4 Willow Emerald Damselfly. One of them took a liking to me and landed on my nose for a while before flying off and landing where I managed to take a few photos. I suspect these may be my last images of this species that I manage to take this year but you never know, if we have a week of mild weather, I may just get lucky next weekend. My latest sighting of a Willow Emerald Damselfly at Nethergong is the 13th December so it is possible weather permitting. It's been a very successful year for the Willow Emerald Damselfly this year at Nethergong and hopefully, they have laid many eggs to overwinter to carry on the next generation next year.

Willow Emerald Damselfly (Chalcolestes viridis) - male

Monday, 29 October 2018

Brilliant Emerald (Somatochlora metallica) Exuviae

Having made the trip to Thursley Common in Surrey earlier in the year to photograph the Downy Emerald emerging and collect some exuviae, I was even more looking forward to a return visit to hopefully photograph the nationally rare Brilliant Emerald emerging and hopefully, collect a few exuviae. I have only encountered this species once before in Kent at Bedgebury Pinetium so a chance to see them emerging at close quarters was not to be turned down. On arrival, the mist was rising off the water and the weather was still. I spent some time looking in the emergent vegetation where a number of Downy Emerald exuviae were still to be found but after quite a search, I found an 'Emerald' emerging which I suspected might be a Brilliant Emerald. I wasn't too sure on the features needed to get a positive identification but having done a little homework, I was aware that the Brilliant Emerald exuviae showed a large dorsal spine on S9 compared to the smaller or absent spine on the Downy Emerald exuviae. I took a few photos and zooming in did reveal the larger dorsal spine on S9 so this was indeed my first experience of a Brilliant Emerald emerging. I spent a while photographing the emergence and during my time that morning, I managed to find a few emerging and collected a few exuviae of the species which was an added bonus. To help with the identification of the exuviae for both myself and other enthusiasts, I have put together a number of photos showing some of the key features needed. As mentioned earlier, one of the main features to look out for is the prominent dorsal spine on S9. Also the long spider type legs and rows of dark spots running down both sides of the abdomen help to identify this species. I will in due coarse photograph a comparison between the Brilliant and Downy Emerald exuviae to highlight the differences of these similar species.

Brilliant Emerald (Somatochlora metallica) exuviae (side view)

 Brilliant Emerald (Somatochlora metallica) exuviae showing dorsal spines and
 prominent spine on S9

Brilliant Emerald (Somatochlora metallica) exuviae showing long antennae and deep serrations on the Labial Palps

Brilliant Emerald (Somatochlora metallica) exuviae (top view)

Brilliant Emerald (Somatochlora metallica) exuviae showing dark spots running
 down both sides of abdomen

Brilliant Emerald (Somatochlora metallica) exuviae showing head shape

Thursday, 25 October 2018

Willow Emerald Damselfly - NEW Behaviour Observed?

I have spent the last few years spending countless hours watching, studying and photographing the Willow Emerald Damselflies of Nethergong and during this time, have managed to find out a few interesting aspects of their behaviour. A few years ago and still today, I have observed them ovipositing into Stinging Nettle stems which I believe was one of the first records of this happening in the UK. Yesterday was another one of those days where I observed some behaviour which I have never seen before. I often stand at the side of the stream and observe the Willow Emerald Damselflies on a couple of Alder trees opposite me and with this, have seen them ovipositing into the branches of the tree over the past few years. They often land on the catkins where normally they fly off deeper into cover to egg lay but yesterday was slightly different. I had decided to sit down opposite the Alder trees and have a drink and something to eat and was observing some pairs in tandem whilst males perched and rushed out every now and then to see of rival males. As I watched, I could see a pair of Willow Emerald Damselflies in tandem which landed on a catkin but this time, they stayed and the female curled round her abdomen and started to oviposit into the catkin itself. I have never seen this before despite watching them for many hours over the years and was intrigued if she was aware what she was egg laying in. They stayed for a few minutes where she clearly did egg lay and then both took off and remarkably landed on another catkin where again, she started to oviposit. Although not the best photos due to the stream being in between us, I managed a few useable shots showing the pair in tandem ovipositing into the catkins.
Willow Emerald Damselflies (Chalcolestes viridis) ovipositing into Alder Catkins
As I continued to observe the pair, I soon become aware of another pair which were also ovipositing into catkins. This then begs the question as to why are they doing this and are they clearly aware of their actions? My initial thoughts related to the catkins getting blown down of falling off the tree during the Winter or in the Spring which would then give the eggs inside a safe passage to the stream where they would then wash up providing a safe sanctuary for the eggs to then develop and emerge in the Spring. The newly emerging prolarva would then already be in the water giving them a better chance of survival. On returning home, I looked through some internet sites to see if I could find any information on this but despite a good search, I failed to find any information on the use of ovipositing into catkins by Willow Emerald Damselflies.  I contacted Adrian Parr from the British Dragonfly Society who kindly emailed me back me and said "Your discovery of individuals ovipositing into Alder catkins is pretty amazing, and I've certainly not come across this before, though I'll double check the literature". This all sounds very interesting and it could be that I have indeed stumbled across some new behaviour not really observed before. Despite it being quite late in the season for them but with some nice weather of late, I made an excellent count of 73 Willow Emerald Damselfly yesterday around the Nethergong site. Hopefully they might make it into November although the weekend temperatures are to quickly plummet so fingers crossed, this is not the last time I get to see and enjoy one of my favourite damselflies this year.
Willow Emerald Damselflies (Chalcolestes viridis) ovipositing into Alder Catkins