Dragonflies and Damselflies

[AlanF]

Really beautiful shots, Alan. Compliments to your wife. Esp. the fist one with the blurred bg is wonderful.

But if I may say so, I believe that both IDs are not correct. But of course, I may be mistaken.

The willow emerald damselfly (chalcolestes viridis) is known to be flying from August to October, sometimes starting in July.
Even if we take climate change into account, this is much too early. And though its wings look like it is freshly hatched - not fully transparent -, its wings should spread slightly.

And when I look at the pattern of the abdomen of both, esp. the first abdomen segment, my guess would be that both are the same species.
The first one is a little bit older and has turned already blue, while the second one is freshly hatched and has to mature a bit.
With the mark on the first abdomen segment and the mostly black rest of the segments, I suppose both are female azure damselfly (coenagrion puella), esp. as they are known to also have a green female form.
The female red-eyed damselflies (erythromma najas) have an almost fully black first abdomen segment.
These two have a first abdomen segment with a waisted colour pattern. That'll be common to azure d.

I hope someone can correct me or substantiate my opinion.

The Willow Emerald began to colonise the UK about 2010. Since then, as numbers have increased, it is being seen earlier each year, which is a function of statistics, and the August to October range is out of date. Here are records for Sussex https://sussexdragonflies.org.uk/speciesAccount.php?species=Chalcolestes viridis. The sightings fit a bell-shaped curve, which is centred in the August to October region, which was the only time range seen when the numbers were very small before 2020 but since then extends much earlier and later, and will become even wider as the numbers increase. I did find it difficult to identify them and welcome help.

 

[P-visie]

Really beautiful shots, Alan. Compliments to your wife. Esp. the fist one with the blurred bg is wonderful.

But if I may say so, I believe that both IDs are not correct. But of course, I may be mistaken.

The willow emerald damselfly (chalcolestes viridis) is known to be flying from August to October, sometimes starting in July.
Even if we take climate change into account, this is much too early. And though its wings look like it is freshly hatched - not fully transparent -, its wings should spread slightly.

And when I look at the pattern of the abdomen of both, esp. the first abdomen segment, my guess would be that both are the same species.
The first one is a little bit older and has turned already blue, while the second one is freshly hatched and has to mature a bit.
With the mark on the first abdomen segment and the mostly black rest of the segments, I suppose both are female azure damselfly (coenagrion puella), esp. as they are known to also have a green female form.
The female red-eyed damselflies (erythromma najas) have an almost fully black first abdomen segment.
These two have a first abdomen segment with a waisted colour pattern. That'll be common to azure d.

I hope someone can correct me or substantiate my opinion.

ObsIdentify says the first picture is an Azure bluet (Coenagrion puella), 99% identification. The second picture is a red eyed damselfly (Erythromma najas), 100% identification.

 

[AlanF]

Thanks for the comments @Maximilian and @P-visie. I think the first is either an immature male Azure damselfly or female. The second still confuses me, despite Obsidentify's identification.

 

[Maximilian]

ObsIdentify says the first picture is an Azure bluet (Coenagrion puella), 99% identification. The second picture is a red eyed damselfly (Erythromma najas), 100% identification.

Thanks for the comments @Maximilian and @P-visie. I think the first is either an immature male Azure damselfly or female. The second still confuses me, despite Obsidentify's identification.

Firstly, both damselflies are females. That I am 100% sure.
The last abdomen segment of both is thicker (ovipositor).
And both have no cerci (see here), the pair of pincers (or how should I call it?) that the male use to connect to females while mating.

@P-visie ID works well with mine for the first to be an azure bluet/damselfly, female. So I think that is settled.
And if ObsIdentify gives 100% for the second, then I suppose that its AI/database is better than we are.
But it is always very (!) difficult to ID damsels and dragons when freshly hatched and not even matured for a few days at least.

Nice puzzle. thank you @AlanF and @P-visie.

 

[Maximilian]

Here are records for Sussex https://sussexdragonflies.org.uk/speciesAccount.php?species=Chalcolestes viridis. The sightings fit a bell-shaped curve, which is centred in the August to October region, which was the only time range seen when the numbers were very small before 2020 but since then extends much earlier and later, and will become even wider as the numbers increase. I did find it difficult to identify them and welcome help.

These sighting curves have a very low database.
I am referring to different sources (internet, classical ID books) etc.
All say willow emerald damselfly (chalcolestes viridis) known to be flying from August to October, sometimes extending to July or November.
This fully meets my personal experience here in Franconia and Bremen.
For example this: (source https://www.ag-libellen-nds-hb.de/, German)



Here the database for Niedersachsen and Bremen is 4k sightings.
I see no reason why willow emeralds should change their behaviour when colonising the UK.
Maybe they've learned to use the left side of the steam

 

[AlanF]

These sighting curves have a very low database.
I am referring to different sources (internet, classical ID books) etc.
All say willow emerald damselfly (chalcolestes viridis) known to be flying from August to October, sometimes extending to July or November.
This fully meets my personal experience here in Franconia and Bremen.
For example this: (source https://www.ag-libellen-nds-hb.de/, German)

View attachment 223909

Here the database for Niedersachsen and Bremen is 4k sightings.
I see no reason why willow emeralds should change their behaviour when colonising the UK.
Maybe they've learned to use the left side of the steam

I presented the data actually observed in the UK, and the behaviour of birds and insects changes with change in climate and indeed global warming so you can't use "classic ID" of a few years ago or extrapolate from the German climate. We now have many examples of events occurring earlier in the year. See for example https://www.rothamsted.ac.uk/news/fifty-year-study-shows-climate-change-pushing-uk-wildlife-out-sync
"Published in the journal Global Change Biology, the study charts the seasonal habits of more than 250 UK species of birds and insects, and shows clear evidence that aphids, moths and butterflies are now on the wing, and birds are laying their eggs, much earlier than they were in the mid twentieth century."

 

[AlanF]

Firstly, both damselflies are females. That I am 100% sure.
The last abdomen segment of both is thicker (ovipositor).
And both have no cerci (see here), the pair of pincers (or how should I call it?) that the male use to connect to females while mating.

I used the image from the British Dragonfly Society used to illustrate the immature male Azure Damselfly (first on the left, second row in https://british-dragonflies.org.uk/species/azure-damselfly/ and attached here, copyright Ritchie 2013.) The anal appendages (cerci) are the same to my eyes, and I have reposted the previous shot for comparison. I am not expert enough to differentiate.


.

 

[Maximilian]

I presented the data actually observed in the UK, and the behaviour of birds and insects changes with change in climate and indeed global warming so you can't use "classic ID" of a few years ago or extrapolate from the German climate. We now have many examples of events occurring earlier in the year. See for example https://www.rothamsted.ac.uk/news/fifty-year-study-shows-climate-change-pushing-uk-wildlife-out-sync
"Published in the journal Global Change Biology, the study charts the seasonal habits of more than 250 UK species of birds and insects, and shows clear evidence that aphids, moths and butterflies are now on the wing, and birds are laying their eggs, much earlier than they were in the mid twentieth century."

I agree with you, that climate change has effect on animals (and plants) behaviour.
Flowers and trees bloom earlier, migrating birds fly earlier, later or no longer at all.

But a damselfly won't change its hatching behaviour that extremely, that it hatches 2 or 3 (!) months earlier than 2 or 5 years ago.
Maybe in 2040 this will happen. But even that would make me want to place a bet, though I don't like bets.

 

[Maximilian]

I used the image from the British Dragonfly Society used to illustrate the immature male Azure Damselfly (first on the left, second row in https://british-dragonflies.org.uk/species/azure-damselfly/ and attached here, copyright Ritchie 2013.) The anal appendages (cerci) are the same to my eyes, and I have reposted the previous shot for comparison. I am not expert enough to differentiate.

I believe and hope that we all don't want to accuse each other of anything or be smart arsees. We want to help each other. And since this shouldn't be a competition, nobody should have to justify themselves, but rather be happy to have learnt something again.

Dragons and damsels have become my big hobby and I have read and researched a lot.
And if I think someone wants to participate from my knowledge, then I am happy to share it.

If I behave like a smart-arse, please let me know. I don't want to.

Playing smart-arse on purpose, the first photo (from the British Dragonfly Society) show a male that I immediately ID as male for those reasons:

• I see cerci
• I see a thin last abdomen segment
• I see the typical mostly blue pattern in the other abdomen segments (females are mostly black)
• I see the typical (for male) black horse shoe mark at the first abdomen segment,
  giving it its German Name "Hufeisen-Azurjungfer" = "horse shoe azure damselfly"

And those two photos together show a wonderful pair of azure damselflies, male and female, and how much they differ.
I can tell you, that I quite often spotted a female azure damselfly, thinking I got a new species, but at home just landed on the hard floor of reality

 

[Click]

I really like the first one with the 45 degree angle.

 

[AlanF]

I agree with you, that climate change has effect on animals (and plants) behaviour.
Flowers and trees bloom earlier, migrating birds fly earlier, later or no longer at all.

But a damselfly won't change its hatching behaviour that extremely, that it hatches 2 or 3 (!) months earlier than 2 or 5 years ago.
Maybe in 2040 this will happen. But even that would make me want to place a bet, though I don't like bets.

You are assuming that the emergence is just an all or or none event that occurs between August and October so to hatch in mid-May would require a shift of 2-3 months. But, the very graph you have presented is roughly a normal distribution, which peaks about 1 Sept and drops to half on 1 Aug and 30 Sept, and is not an all-or-none step function. It falls to about 10% on 1 July and some non zero values in June. Just a small change will push the tail more into May where some will be observed, it doesn't require a 2-3 month shift. Laboratory experiments on damselfly hatching have found a 5 deg increase of temperature gives 3 week earlier shift in hatching. Biological events can change quickly. For example, from the Guardian newspaper this week:

"Midsummer butterflies are on the wing in early May after a sunny spring prompted one of the most advanced seasons for Britain’s Lepidoptera on record.
The Lulworth skipper – usually found in June and July – is flying at Lulworth Cove in Dorset, the chequered skipper emerged in April rather than mid-May in Scotland and the first swallowtail, which is most common in mid-June, was spotted in Norfolk on 1 May.
“The chequered skipper is a butterfly you can set your calendar by – it typically comes out 13-15 May,” said Tom Prescott, the head of Butterfly Conservation Scotland. “I was absolutely staggered when it was seen on 26 April.”"

Midsummer butterflies spotted early in Britain after sunny spring

Scientists fear early emerging insects may fall out of sync with pathogens, predators or availability of food

www.theguardian.com

 

[Maximilian]

You are assuming that the emergence is just an all or or none event that occurs between August and October so to hatch in mid-May would require a shift of 2-3 months. But, the very graph you have presented is roughly a normal distribution, which peaks about 1 Sept and drops to half on 1 Aug and 30 Sept, and is not an all-or-none step function. It falls to about 10% on 1 July and some non zero values in June. Just a small change will push the tail more into May where some will be observed, it doesn't require a 2-3 month shift. Laboratory experiments on damselfly hatching have found a 5 deg increase of temperature gives 3 week earlier shift in hatching.

Alan, your assumption about what I am assuming is wrong. I said:

All say willow emerald damselfly (chalcolestes viridis) known to be flying from August to October, sometimes extending to July or November.

So I am fully aware that the bell graphs are showing some early sightings while the majority is later.
And the graph I presented is showing this. As this is not a one-year graph but an accumulation of several years, your earlier approach because of higher temps is already included and visible by a few in June sightings. We had record year after record year throughout the last two decades.
And a June sighting doesn't mean it was seen on June 1st or 15th. It could also be a very late June sighting.
I don't have the raw data.
But when we say the damselflies start hatching in August and in warm summers also in July or even late June, then my calculation of 2 to 3 months earlier is still correct. And I am referring to the bell curve and not to "an all or none event".

 

[Nemorino]

R5 + RF 200-800
@200mm, f/10

 

[Click]

The subject comes into sharp focus in this magnificent bokeh.

 

[AlanF]

ObsIdentify says the first picture is an Azure bluet (Coenagrion puella), 99% identification. The second picture is a red eyed damselfly (Erythromma najas), 100% identification.

I found a photo of an immature female Red Eye damselfly and it is identical to my wife's photo. https://shropshirebirder.co.uk/xxredeyeddamselfly.html
Obsidentify is becoming one of my favourite apps - thanks for the heads up on it, but it would be even better if it added info like the sex and growth stage. Here's my shot of it from the R5ii + RF 200-800mm at 455mm as I was looking over her shoulder. And below is a genuine female Willow Emerald I took last year.


.

 

[Maximilian]

Today's series of a four-spotted chaser, that was friendly enough to pose for me.
R6m2+100-500+1.4x@700mm close to MFD and almost FF.

 

[Maximilian]

Here is a scarce chaser that has already matured somewhat.
You can still see some orange at the edge of the abdomen. But most of it is already blue.
R6m2+100-500+1.4x@700mm close to MFD and almost FF.

 

[Maximilian]

Downy emerald IF
R6m2+100-500+1.4x@700mm, f/14, 1/2000, ISO6400

 

[Click]

Amazing details in your shots. Well done, Maximilian.

 

[Maximilian]

Amazing details in your shots. Well done, Maximilian.

Thanks, Click
The DIFs would have been even better if I had set the ISO lower.