Pseudagrion microcephalum (Rambur, 1842) 瘦面細蟌

Genus : Pseudagrion

Pseudagrion microcephalum is a very common in ponds, lakes and drains. The male bright blue with black bands.

It can be confused with many other common coenagrionids, including Archibasis species and Argiocnemis rubescens, all of which fall into the same size range (S hw, 16-24 mm) and have a similar pattern of blue on black.

It is difficult to separate from other blue Pseudagrion species, but Pseudagrion microcephalum is by far the commonest and most widespread member of its genus and the only one known from disturbed habitats.

Male Pseudagrion microcephalum skimm just few inches above water surface (above photo insert).

The female is light brown with obscure greenish markings. Mating start at midday throughout  the afternoon.

After insemination the pair may remain in tandem for well over an hour, skimming the water surface and resting frequently on lily pads. Females often submerge completely to lay their eggs in the stems of water plants.

Reproduction of  Pseudagrion microcephalum (Rambur, 1842)

The male using his genital claspers located at the tip of his abdomen to  grab hold of her by the pro-thorex. The two will form a circle while the female aligns her genitilia with the secondary genitilia of the male located at section two (S2) of abdomen. The male then deposit his sperm into the female.

After copulation, the male will continue to hold onto the female's neck to prevent other males from mating with her. The male will fly around with the female while she lays her eggs, often guiding her to the most ideal spot for the eggs. Once a location has been selected, the female will insert her ovipositor, a knife-like egg-laying organ, into stems of growing plants.

Females always lay copious amounts of eggs in order to ensure that at least some will hatch and fully mature into adult dragonflies.

Diagram below : Male and female Blue Sprite Damselflies in tandem position

Identify a female Pseudagrion microcephalum (Rambur, 1842)

An immature and matured female Pseudagrion microcephalum (Rambur, 1842) are so different in color that it often mistaken as another species.

An matured female's greenish blue color is similar to few other species and again often wrongly identified as the same species.

One can  tell it is  a female Pseudagrion microcephalum (Rambur, 1842) by the 3 unique black spots on each side of the thorax.

Above :  A male Pseudagrion microcephalum (Rambur, 1842)

The male damselfly is brightly blue  in color with black pattern on abdomen and blue thorax with black marks. Its long and slender abdomen is black in color with blue rings. There is the blue tip at the end of abdomen. 

The female are look the same except pale blue to grayish-green in color. When Blue Sprite Damselflies are at rest, they held their wings closely folded up vertically over their thorax. 

Then the female will return to the water and lay her eggs, usually with the male still in tandem position. 

Damselflies lay their eggs in the plants under the surface of water. Female damselflies have their blade-like ovipositor for making an opening in the plant for her eggs.

Some other damselflies female lays eggs alone with no male around.

Below : A female

Blue head, Blue face and eyes are Blue too.

A few species of damselflies in Sabah are blue and look similar. One can easily  mistaken Pseudagrion microcephalum as Ischnura senegalensis.

We can tell it is a Pseudagrion microcephalum by its Blue eyes and bright Blue face.

Blue Sprite - The Blue damselfly

Pseudagrion microcephalum (Rambur, 1842) Blue Sprite Damselflies are one of the most common damselflies found in Sabah. They can easily be found near running water or still water. They usually rest on the plants in the middle of ponds or at the water edges.

In warm sunny days, you can see them flying over the water completing for a good perching position with other damselflies.

This slender blue damselfly flies gracefully above pond and stream. The most abundant of all damselfly species, this beautiful blue damselfly can easily be spotted in grass. The males are beautifully blue, while the females are dull light green.

Which one is Pseudagrion microcephalum ?    Which is Ischnura senegalensis ?

I thought my pond has only one blue damselflies. But why some are longer in sizes ? Until after careful observation I noticed they are actually 2 different species of damselflies. The Pseudagrion microcephalum  and the  Ischnura senegalensis

复眼大部分是水青色·   胸部水青色，侧视前端有二条黑色条纹·  腹部背侧黑色，第八至十节水青色·  第十节背侧黑色·

INDEX : Dragonfly     September 15, 2007 01:18:34 PM