Saturday, February 26, 2011

17. Agriocnemis minima (Selys, 1877)

Number: 17
Family: Coenagrionidae
Genus: Agriocnemis
Species: Agriocnemis minima
Common name(s): N/A
Thai name(s): แมลงปอเข็มเล็กมินิม่า
Habitat: Exposed ponds/lakes/ditches (in the grasses) lowlands/uplands
Province(s) sighted: Widespread (Khon Kaen); Nam Nao NP (Petchabun); Khao Yai NP (Nakhorn Ratchasima); Khao Kitchacut/Khao Soi Dao (Chantaburi); Phu Rua NP (Loei); farmer's pond (Prachaub Khiri Khan).
Sightings (by me): Common and widespread
In flight (that I have seen): March-December (though probably all year)
Species easily confused with: Agriocnemis pygmaea; Agriocnemis femina

Agriocnemis minima is one of seven species of Agriocnemis to be found in Thailand. It is also one of the most common, second only to A. pygmaea. There are supposed to be three common Agriocnemis species found in paddy fields throughout Thailand but I have only found two to be common in Khon Kaen and the surrounding areas. A. femina femina doesn't seen to be present. Agriocnemis is a tiny genus and very often overlooked, as they are tiny. The other problem is correctly identifying the different species. I think differentiating the males is easy, but the females are far more difficult.

The male
The male is easy to identify, especially the adult. It has a green/black striped thorax and a vivid orange abdomen. It also has a distinctive "mask" mark on the 2nd segment of the abdomen. The other big difference on this tiny species, are the anal appendages, which are very prominent (see photo).







The caudal appendages
With such long appendages, this species is the easiest to identify in the genus.


The female
The female is far more difficult to identify. Like other Agriocnemis species, the female changes colour as it matures. It starts off a bright orange/red colour and darkens as it matures, ending up grey (as the first female shown). 



The sub-adult female
This female is at the "mid-stage" of its colour change.



The teneral female
This newly-emerged female is at the very early stage of its colour change.


This species can be found in any field near a waterway. It particulrly likes to be in the open, among grassy areas that grow near swampy areas, ditches and ponds. I think it can be found all year round, though it seems to be more abundant in Khon Kaen from the rainy season (July) until around March. But don't forget... you really have to look closely for it as it is so small.