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!

2 comments:

  1. hi dennis, nice and interesting photos, i am interested in the oviposition of the orolestes species. I would like to know if you know how far from water was this specimen ovipositing? there was near a water course or pond/lake?
    do you saw other species ovipositing?
    thank you, julian

    ReplyDelete
  2. Hi Julian.
    Thanks for your comments.
    Unfortunately, this is the only species in the genus Orolestes found in Thailand (that I know of, anyway).
    However, it really is a beautiful species. This specimen was, indeed, close to a water source. It was ovipositing into the bark of a tree (no idea of the species). The tree, itself, was at the edge of a small, clay-based and almost featureless ditch (I was extremely surprised to find so many male specimens here, as well as at other similar ditches in the locality that had the same species of tree). The photographed female was the only female specimen I saw (and have ever seen) and while she was ovipositing a male was always present (can be seen in some photos). The female also oviposited just over the water's edge. If you look closely at the bark, you can see the tiny holes that she has left. The process took around 20 minutes, with a few breaks in between. She would oviposit for 3-4 minutes and then seemed to rest momentarily, before continuing (always with the same male close by). Eventually, and to my surprise, a different male swooped in - during mid-oviposition - and grabbed the female, carrying her high into the treetops in the distance. Once she had gone, the majority of the males in the same tree (around 15) seemed to disperse too.
    Thanks, Dennis.
    I do have a few photos of Lestes sp. ovipositing in tandem http://thaiodonata.blogspot.com/2011/07/136-lestes-praemorsus-decipiens-hagen.html

    ReplyDelete