Monday, February 28, 2011

40. Prodasineura autumnulis (Fraser, 1922)

Number: 40
Family: Platycnemididae
Genus:  Prodasineura
Species: Prodasineura autumnulis
Common name(s): Black Threadtail
Thai name(s): แมลงปอเข็มหางเข็มดำ, แมลงปอเข็มเรียวดำ
Habitat: Tree-lined or exposed rivers, streams and ponds (uplands & lowlands)
Province(s) sighted: River Chi (Khon Kaen); Nam Nao NP/environs, waterfall, Lomsak environs (Petchabun);  Phu Kradueng, Phu Rua NP/environs (Loei); Widespread (Chiang Mai); Widespread (Chiang Rai); Khao Yai (Nakhorn Ratchasima); Nakhorn Nayok; Khao Soi Dao NP, Khao Kitchakut NP/environs (Chantaburi).
Sightings (by me): Extremely common
In flight (that I have seen): All year

When I first visited the River Chi, Khon Kaen back in early 2008, I spotted my first ever Prodasineura species - Prodasineura autumnulis. I took a number of photographs of both the male and female. In this area they are in small numbers, but you often see one or two there. For over a year, I thought that the sub-adult male was fully grown. It wasn't until I went  to another place south of Nakhon Sawan that I noticed the adult males are jet black. At first I thought it was a different species, but research proved otherwise.

The male (various stages)
The adult male is black on the thorax and abdomen and also becomes slightly pruinosed with age. It is easily frightened and quite hard to photograph. This is the most common stage.

As the male ages, it changes slightly. This specimen, I captured in Nakhorn Nayok, has slight pruinescence to the side of the thorax (photo 28/03/2011 - added 02/04/2011) ... 

... and this one is completely pruinosed save a small greenish-bronze? part of the thorax. I must admit, this is the only specimen I have seen like this. It was at a largish waterfall in Lomsak province, Petchabun (14/07/12). Though it looks right, it acted differently to all the others around it and the colours add to the mystery. Maybe, just maybe, it may be a slightly different form. Can anyone shed light on this?

The teneral male
This male has just emerged and you can still see his exuvia at the base of the stick he has climbed.

The female
The female is almost identical to the sub-adult male, but the abdomen is far more robust. Like the sub-adult male, it tends to hide away and is less commonly seen.

A newly emerged female...

Although it is called Prodasineura autumnulis, it is common all year round. It prefers slow moving rivers and streams, but I have also seen it at small ponds.

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