Friday, 4 September 2015

Chlorogomphidae - just beautiful

Over these 2 years I have been lucky enough to encounter many species from the Chlorogomphidae. A tip of the Iceberg, but I am not complaining. Almost all are spring species, with a few lingering on into early summer. This year I caught up with a species that earlier I had failed to see, although I went looking for it in Cao Bang Province in an area where it is not uncommon. This was magical Chlorogomphus papilio. There are actually quite a few Chlorogomphids with colorful wings, but this species stands out. In most species it is the female that has colorful wings, but in C. papilio it is the male that is wonderfully striking. It inhabits medium-sized streams with some rocks and I have encountered it at least at 4 different sites scattered around the province.

This is one of the first specimens I observed. I had already seen it the evening before, hunting high over the forest, but the second day could take a few photos of it. Even at long distance with a telephoto lens it is recognizable! I was so very excited. In fact, at a distance the translucent parts are difficult to see and it truly looks like a butterfly.
This is another male in hand. They have quite a slow and deliberate flight when patrolling.

Scan of a male in dorsal view. Luckily this species is not all that rare, although the river systems it inhabits are vulnerable to all sorts of pollution.

 Another magnificent species is C. auratus. This species was considered near-threatened according to IUCN, because of the scarcity of records, although it had been found at Tam Dao and in Central Lao PDR. It is however one of the commoner species and I have seen it in Yen Bai Province, in Cao Bang Province, in Lang Son Province and in Ninh Binh Province, and sometimes in surprisingly disturbed areas. The female has beautifully colored wings.

A female posed in Cuc Phuong, where it co-occurs with C. nakamurai, although much less common
In this dorsal view scan of a female the golden-brown wings with dark-brown tips are more obvious.
And the last colorful-winged species I would like to introduce here is female C. nakamurai. This female is very similar in wing-pattern to C. albomarginatus, but is a shade lighter and has dark wingtips. Apparently this species is also known from former Ha Tay Province, but I do not know the location of Mount Tan Vien. The only well established population seems to be in Cuc Phuong National Park, where it is in fact surprisingly common in the few available shallow streams. But water availability is low in the forest, so in absolute numbers it is certainly not abundant. Males patrol incessantly, but females drop down from the canopy and then flutter in dark shady places close to the surface. They keep on moving about while ovipositing left and right and are not easy to take pictures of in their dark surroundings.

A female fluttering low over leaf litter in the dark. Compare the female of C. albomarginatus, a mountain species, on Sebastian's blog.

An old female in dorsal view. Note the dark wingtips and brown, not black coloring.

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