A trip To Xuân Son National Park

Xuân Son National Park is the southeastern most extension of the Hoang Lien Son Mountain Range. 
Only three peaks rise more than 1000 m a.s.l.

Xuân Son National Park (130 km northwest from Hanoi, in Phu Tho Province) is a great place with its wide variety of clear streams flowing through untouched karst forest, offering superb Odonata watching. 

Curiously, this national park has been an overlooked hot spot for Odonata until December 2009, when Phan Quốc Toản explored the area. It was certainly the first time that survey on dragonflies was undertaken there. 

This national park is renowned for the richness of Caloptera damselflies, with some rare and endangered species. The best time (for Caloptera at least) is after the rainy season, from September to December.
 

I visited Xuân Son at the end of October 2013 and I was not disappointed at all! For a long time, I had wanted to go there, but I always found a good reason (e.g. autumn bird migration) to avoid a 3 hours motorcycle ride. But after reading the recent adventures of Tom Kompier on his blog odonatavietnam, I finally kicked my lazy butt into action!

One of the highlights of  Xuân Son National Park is the newly (2011) described Matrona taoi, known only from Xuân Son and a locality in central Vietnam (Quang Binh Province). A Matrona species with metallic green abdomen and brown-reddish wings, lacking any milky coloured reticulation at the wing bases of the male (unlike Matrona basilaris for example).

Male Matrona taoi. This conspicuous species is easy to find - but not abundant - in appropriate habitat (and at the right time of year of course) at Lâp and Coi villages (core area of the NP), at ca 400-450m a.s.l.

I spotted M. taoi at this quite open stream at the edge of a dense forest (2 shots, same place but different angles), near the dam between Lâp and Coi villages. I also found there Matrona basilaris, Rhinocypha perforata, Neurobasis chinensis, Euphaea masoni and Euphaea decorata. In fact, M. taoi was in the more shady section, with vegetation on both banks (in the middle part of the pic on the right). I also netted there a female Boyeria karubei and a female of the recently described Planaeschna guentherpetersi.

A slow-moving, well-vegetated shady stream in untouched (lowland evergreen) forest in Lâp village, habitat of Matrona taoi, Noguchiphaea yoshikoae, Atrocalopteryx coomani, Cryptophaea vietnamensis, Rhinocypha arguta and Vestalaria miao. Another goody commonly found there was Coeliccia sasamotoi - recorded at just a handful of sites, in Vietnam and Laos. Tom Kompier observed also some Coeliccia poungyi in this kind of habitat (to my knowledge, Xuân Son NP is the only known locality for Vietnam of this species). More interesting, he found Coeliccia uenoi, a very rare species previously known only from Cuc Phuong NP (about 120 km southeast as the crow flies) ! Fantastic!

A clear, man-made pond, habitat of Matrona taoi (2-3 males spotted), Rhinagrion hainanense, Coeliccia sasamotoi, Ceriagrion fallax and C. chaoi, the two latter in the most open part of the pond, where a carpet of algae can develop - on the right of the pix (Thanks Tom for showing me the place!).

Some photos taken during this trip :

Male Matrona basilaris.

A new species for me. In Vietnam, it is a local and quite uncommon inhabitant 

of forested streams both in lowland and mountains.

A territorial wing-clapping of a male Atrocalopteryx coomani - a northern Vietnam endemic.

Male Vestalaria miao. 

Another most-wanted species at Xuân Son NP. Described in 2001, well distributed in southern China, but known from very few localities in Vietnam (Huu Lien Nature Reserve, Xuân Son NP at least).

Males are easily distinguished from other Vestalaria ssp. by their very short inferior appendages (about 1/4 the length of the superiors).

Male Noguchiphaea yoshikoae. 

Looks superficially like Vestalaria miao, but caudal appendages completely different. Found at ca 400m a.s.l at Xuân Son National Park, which is one of the lowest elevation known for this species. In Vietnam, recorded at least from 2 other localities: Ba Vi and Tam Dao NPs.

A territorial wing-clapping of a male Neurobasis chinensis.
Probably the commonest Caloptera in Vietnam - with Aristocypha fenestrella.

Male Rhinocypha arguta. 

One of the highlights of this trip. Described from Phu Kradung mountains (Thailand) in 1997, actually only known from 4 separated sites in Thailand and Vietnam (Cuc Phuong, Xuân Son NPs). 

 

Female Rhinocypha arguta.

  

Female Rhinocypha perforata for comparison.

A common species throughout its wide range, but surprisingly scarce around Hanoi.

  

Male Rhinocypha perforata.

Male Euphaea decorata.

Male Rhinagrion hainanense. 

This gorgeous creature has been described from Hainan in 2001, and is actually known from southern China, Thailand, Laos and a handful of sites in northern and central Vietnam. Apparently, this stream-dweller can also breed in forest ponds (I had another sighting at a man-made pond at Tây Thiên/Tam Dao NP).

  

Female Rhinagrion hainanense. 

Male Coeliccia sasamotoi, a recently (2011) described species, recorded 

at just a handful of localities, in Vietnam and Laos.

Male Coeliccia onoi.

Pair of Ceriagrion bellona in tandem. 

A first record for Vietnam, found by Tom Kompier alias “eagle eyes” one week before this trip.

 Pair of Ceriagrion fallax in tamdem. 

A rather common species in northern Vietnam, in sub-montane and montane localities.

Female Planaeschna guentherpetersi ovipositing in a dead trunk, 30cm above the water. 

Also a newly described species (2013) from Xuân Son National Park.

Female Boyeria karubei. 

A first record for Vietnam, by Tom Kompier also. 

 Female Boyeria karubei in hand.
A large-sized and really stunning dragonfly.

 I also bumped into this nice guy, a Green Pit Viper (Trimeresurus sp.). 

Due to its green color, it is hard to see. Better not to be bitten by any of the Green Pit Vipers, their venom – while not usually deadly – is quite strong and can cause havoc in the human body.

Great river in pristine forest. 
     What other surprises next year ?

More informations about Caloptera damselflies at Xuân Son National Park here.

Mr Lâm, at Du village (3 km from Lâp village), can provide basic accommodation at the cost of 150.000 dôngs/night.

Tramea virginia (Rambur, 1842)

Tramea virginia is a quite large libellulid characterized by very large basal patches to hind wings (obvious even in flight). This late season species can be seen (in my area) from August to November-December.

This male visually track a prey.

Tramea typically have bases of hind-wing more or less broadly marked with a large or irregular opaque spot. In fly, this creates the impression of them carrying bags; hence they are commonly known as “saddlebags gliders”!

A male viewed from above, showing well its famous “saddlebags”. This shot has been taken in mid-November with my old megazoom camera bridge (an interesting concept for a “polyvalent naturalist”, but once you have tasted a DSLR camera, you forget it quickly... Nevertheless, if sharpness is the least of your concerns, it remains a great tool). 

Another male, posed upon release. I didn’t choose the best support. Tramea loves twigs, not leaves! But a leaf is a more comfortable place for recovering...

Tom Kompier recently found the wind blown vagrant T. transmarina euryale at the marsh of Van Long in northern Vietnam (Ninh Binh Province). This is the first record of this species for the country. The most obvious differences between transmarina euryale and virginia concern the hindwings markings (notably reduced in transmarina, extending distally to distal end of discoidal cell and involving nearly whole of anal loop in virginia) and the secondary genitalia (hamules slightly overlapping the genital lobe in transmarina, markedly longer than lobe in virginia). The latter feature is obvious even on perched individuals – if you have binoculars!

Close-up on the secondary genitalia. 

Note the very long hamulus, greatly overlapping the genital lobe - three years ago I thought these things were penis and testicles :))

Tip of abdomen, male, lateral and dorsal views.  Cerci very long, as long as the last three segments of abdomen.

The female is similar to male in head/thoracic colour pattern. Apart sexual characters, the most obvious differences between sexes are the colour of abdomen (amber-brown in the female, bright brick-red in the male; the last three segments are black in both sexes) and the basal marking on hind-wing (amber-yellow reticulation in the female, red in the male).
Anal appendages nearly as long as in the male, black, straight, very narrow.

The female above was caught as she was flying above a recently harvested rice field, in company of many Pantala flavescens. Both are great gliders! 
Many Tramea species engage migratory flight, but not to the same extent as seen in Pantala ; during the flight of the latter a good proportion of specimens of Tramea are to be seen accompanying them. All Tramea spp. appear to be physically adapted for gliding flight, and thus potentially for migration, by virtue of their broadly expanded hind wings, and extreme vagrancy (Michael L. May, 2012).

What the heck is that? If you answer “her eggs”, it is time to immerse yourself in the anatomy of Odonata! No, these bugs are water mites larvae. For more details about these ectoparasites, click here (an excellent post on Jim Johnson’s blog).

Female, posed upon release. Again, not the best support!

Spot in hind-wing very large, extending distally to distal end of discoidal cell and involving nearly whole of anal loop. Within this mark, the reticulation is amber-yellow in the female (left), bright red in the male (right), well defined against the dark background.

 Vulvar scales of great size, deeply cleft into two keeled processes, rounded at apices.

T. virginia is known from India, Myanmar, Bangladesh, Nepal, China, Taiwan, Japan, Korea and Vietnam. There is a single old record from Thailand.

I spotted it at ponds, marshes, often in human altered habitats. It is probably a fairly common species, but surprisingly I had few photo opportunities.

Due to its strong migrating power, Tramea basilaris is likely to appear as vagrant in Vietnam (apparently already recorded).