Sunday, June 12, 2011

127 Brachydiplax sobrina (Rambur, 1842)

Number: 127
Family: Libellulidae
Genus:  Brachydiplax
Species:  Brachydiplax sobrina
Common name(s): Little Blue Marsh Hawk
Synonyms: Brachydiplax gestroi (Selys, 1891); Brachydiplax indica (Kirby, 1889) *
Habitat: Large, exposed rivers, small lowland forested ponds
Province(s) sighted: Large river, Lomsak environs (Lomsak); River Chi, Khon Kaen environs; small lowland forested ponds (Udon Thani province)

Sightings (by me): Rare (though common in one area of Udon Thani province)
In flight (that I have seen): July-October


A really difficult genus to ID is Brachydiplax. However, with the help of Noppadon Makbun and Oleg Kosterin, I am now able to ID species in the field (hopefully). With Brachydiplax sobrina I am leaning towards their preferred habitat being large exposed rivers, as opposed to marshy/weedy ponds preferred by other species in the genus - though I could be completely wrong, especially as its common name is Little Blue Marsh Hawk.


(Yes, I am wrong ... I have seen this species thriving at small farmer's ponds.)
The male
The male is almost identical to other species in the genus. However, it can be identified by its antenodal crossveins. This species has 7 as opposed to 8-9 of B. farinosa. I first saw this species back in 2008, I saw it again briefly in 2011 and then recently in Udon Thani province where it seemed fairly abundant, though mature males were hard to approach.

An unfortunate ending ...


The young male
Similar to the older male, but the thoracic markings are still visible.


The best way to separate this species ... 

I haven't managed to spot the female, though it was photographed recently at the same place in Udon Thani, by my fellow Issarn dragon hunter, Joe Hartman. I will return to find her one day soon.

Saturday, June 11, 2011

126. Orolestes octomaculatus (Martin, 1902)

Number: 126
Family: Lestidae
Genus: Orolestes
Species: Orolestes octomaculatus
Common name(s): N/A
Thai name(s): แมลงปอเข็มป่าผู้ปีกลาย, แมลงปอเข็มปีกแผ่ใหญ่แปดจุด, แมลงปอเข็มปีกกางแผ่นปีกลาย
Habitat: Exposed ponds on the edge of forests (lowlands)
Province(s) sighted: Phu Wiang NP & Phu Pha Man NP (Khon Kaen); Nam Nao NP (Petchabun).
Sightings (by me): Uncommon
In flight (that I have seen): April-June (longer, I'm sure)
A spreadwing that is widespread (that's a mouthful!), but uncommon and had eluded me until now, is Orolestes octomaculatus. I saw a male for the first time on June 11, 2011. However, today (June 18, 2011) I returned to find the female. Where I had seen three males at Tad Fah Waterfall, this time there was only one and I thought my luck was out. So I decided to visit Phu Wiang National Park itself about 20 kms away from the waterfall. About 300 metres inside the entrance there was a tiny and muddy clay pool to my left with a few bushes and trees overhanging and I thought I may as well have a look, seeing as though I was there already. To my amazement, there were around 20 male O. octomaculatus resting out of the sun under the leaves of a small tree. I managed to improve my photos from the previous week (though it took a long time as they fly high up into the tree the moment you even breathe) and then tried to take even more shots (sometimes I'll take hundreds of photos of the same individual just to make sure it's OK). As I was about to shoot again, I noticed something above it on the same branch... I took a photo just to see what it was and it turned out to be a female! Yet, it was in the strangest position I have ever seen. Watching her for about 20 minutes, I discovered she was ovipositing into the bark of the tree that overhung the pond. See female below for more information.

The male
It is easy to distinguish because of its beautiful wings, blue/green eyes and S9-10 are bright blue and it has large claspers. It is also large for a damselfly.


Lateral view. This shows the thoracic stripes very well indeed.


Here's looking at you ... 



Thoracic view of another male. This shows the thoracic stripes very well indeed.



The female
The female is rather dull in comparison, but what she did amazed me... 
The standard dorsal view. Note the 3 1/2 wings. Those boys are rough with her...



A slightly different angle...


Thoracic view. Note how much cover from the leaves she had...


And now for the acrobatics. Here you can see she is ovipositing by first making a hole into the bark...


You can clearly see that she twists her abdomen (from S5 down) to make the hole bigger (or whatever she is trying to achieve for the eggs)... This is something I have never seen before.


Bear in mind that the female was deep inside the tree and I had to shoot from a fair distance with flash, using a 300 mm lens... and this is what I saw at first... a male with a strange-looking thing above it. Actually, it was the female, carefully guarded by the male throughout the whole procedure... It really was a bizarre position.


More bizarre positions later... she slowly moved around the bark of the tree that overhung the pond and carried on doing this for about 20 minutes (you can see the little holes in the branch that she has made). Eventually, the guarding male interlocked with her and they flew high up into the tree canopy. As soon as this happened, most of the other males disappeared too.


Though it was a quiet day on the odonata front, today was special for me, as I saw something I am not sure many people have ever seen. It was an amazing spectacle for a girl with only 3 1/2 wings to produce. 

Then again, a stupid fat idiot travelled 400 kms (2 round trips) to see this species. Was it worth it? Of course it was. And my next trip... Nam Nao National Park (again). However, this time on my motorbike from Khon Kaen to Nam Nao... the distance on a 110cc bike makes me want to cry!

Thursday, June 9, 2011

125. Pseudagrion australasiae Selys, 1876

Number: 125
Family: Coenagrionidae
Genus: Pseudagrion
Species: Pseudagrion australasiae
Common name(s): Blue-headed Sprite, Look-alike Sprite
Thai name(s): แมลงปอเข็มบ่อออสเตรเลีย, แมลงปอเข็มบ่อฟ้าใหญ่
Habitat: Exposed ponds and lakes (uplands & lowlands)
Province(s) sighted: Khon Kaen environs; Nam Nao NP/environs (Petchabun);  Widespread (Chiang Mai); Khao Yai NP (Nakhorn Ratchasima); Khao Kitchakut NP (Chantaburi).
Sightings (by me): Fairly common
In flight (that I have seen): April-December
Species easily confused with: Pseudagrion microcephalum; Cercion malayanum;

One species that I'm sure I have seen a number of times is Pseudagrion australasiae. However, unless you are very, very close to it, it is hard to tell the difference between P. australasiae and P. microcephalum. Having studied photos for a long time, one difference I have noticed (I think) is that P. microcephalum is a brighter, more vivid blue. Whereas P. australasiae is a slightly more muted blue. Also, P. australasiae is slightly bigger but has shorter caudal appendages compared to that of P. microcephalum

The male
As mentioned above, the male is very similar to the male of P. microcephalum. If you see two together, it is easier to compare as P. australasiae is duller in colouration and is also larger. Also, P. microcephalum is far more common in Khon Kaen and the surrounding areas. 


 









P. australasiae is slightly larger than P. microcephalum (a good way of IDing if seen together)



The superior (top) appendages are shorter than those of P. microcephalum



dorsal view ...





A youngish male
This one hasn't quite developed that shimmering blue colour.


The 'adult' female...
The female is very similar to other females in the genus. However, for me, I was lucky recently. At at large, shallow lake I saw recently at Khao Yai, Nakhon Ratchasima province, I spotted many males and females, including the female at all stages. P. microcephalum wasn't present, making identification much easier.

Here is a very old female.


The adult female is blue in colour.


The 'mid-stage' female...
Here, we have a mid-stage female, which is just showing signs of blue on the thorax.


The 'young' female...
This is a young female, which is brown in colour. There were many of these early in the morning. However, once the sun came up, they all vanished into the bushes and trees.

Monday, June 6, 2011

124. Epophthalmia frontalis frontalis Selys, 1871

Number: 124
Family: Corduliidae
Genus: Epophthalmia
Species: Epophthalmia frontalis frontalis
Common name(s): N/A
Thai name(s):แมลงปอป่าตาเขียวปีกใส
Habitat: Unknown
Province(s) sighted: Khon Kaen environs (Khon Kaen)
Sightings (by me): Commonly seen in flight but never perching (4 specimens - all seen dead along the roadside, one found dead in a house)
In flight (that I have seen): June-October (probably longer)

Who says you need lots and lots of patience to capture photos of dragonflies? Try cycling around the country roads and you may get a nice suprise. I did anyway. About 10 kms outside Khon Kaen, along a quiet country road, I cycled past a large, dead dragonfly, probably hit by a car. I stopped and picked it up. Unsure of the species, I carefully placed it into a small pouch I have under the seat where I normally keep my phone and cycled another 20 kms before returning home. Fortunately, it survived the journey and I was able to get good photos of it, before the ants moved in and left just a pair of wings! I searched the Internet and thought it was Epophthalmia frontalis frontalis, which was later confirmed as correct by Noppadon Makbun. Since then, I have spotted 2 more specimens (2 males and 1 female in total). Maybe they are more common that I thought in Khon Kaen, but rarely seen as they reside high up in the trees.

The male
Here is one of the males 'in situ'. Well, he is totally dead, but I just wanted his to look a little bit more natural and I think this is how they rest.



... and back to the better-for-science shots.




Wing venation 
This photo shows the distinctive hyaline wings with slight yellow colouration to the base of the hind wings.

Caudal appendages
Views of the terminal segments which also help with identification.

 Lateral view ...


Lateral view (from a slightly single angle) ...


Dorsal view ...


Basal view ...


The female
I have finaly managed to find a female ... and again, it is dead! Thus, more unnatural shots ... though probably better from an ID point of view. Similar to the male, but slightly more robust. Also, note the eggs still attatched to the appendages.




Wing venation ...
 with broken tips - this was the better side! I think she was quite old.


The female appendages ...
amazing how the eggs are still attatched!




Male vs. female
I was lucky enough to also spot a female (this was my first female sighting), though she is really smashed up. It does, however, allow me to spot a few differences - the abdomen is more robust, the wings have a brown tinge (not clear like the male) and don't have any yellow colouration at the base. The eyes don't seem to be metallic either, though this could be simply because it has faded.