No. 19 Dragonflies and Damsel flies




[Remember to click on the photograph to enlarge the image]



Broad Scarlet Dragonfly (male) in flight

Now that the spring bird migration has largely finished, there are fewer unusual species that I can get out to watch or photograph. So, in an effort to find a different aspect of natural history to discover and photograph, I have been out looking at Dragonflies and Damsel flies during the last month or two. And what an impressively colourful selection of insects I have found. All of the individuals illustrated below were found either in Secret Valley or at Ayia Varvara.



Dragonfly
Broad Scarlet - female


Dragonfly
Broad Scarlet - male

Dragonflies and Damsel flies are all members of the Order of insects called 'Odonata' (which means 'toothed', from their protruding mouthparts). They are all long, slender-bodied insects with two pairs of wings, each with an intricate network of veins. They all have large compound eyes but have only short or inconspicuous antennae. The head (and eyes), thorax and abdomen can all be the same or different in colour and pattern,  according to species, sex and age.


Dragonfly
Southern Skimmer - male


Dragonfly
Southern Darter - male

The two groups (dragonflies and damsel flies) are fairly easily identified by the following characteristics. The sub-order Zygoptera (the Damsel flies) have similar sized wings, while the sub-order Anisoptera (the true Dragonflies) have unequal wings. The resting damsel fly generally holds its wings vertically over the body, or partly spread, whereas the true dragonflies always rest with the wings fully outspread. The dragonfly hind wings are also usually broader than the front pair.

Dragonfly
Red-veined Darter - female



Dragonfly
Red-Veined Dropwing- male



Dragonflies are generally day-flying insects and rely almost entirely on sight for carrying on their daily lives. In many species the head appears to consist of little but the compound eyes, which generally meet (or almost meet) on top of the head. The mouth parts are largely hidden on the underside of the head, beneath the compound eyes. The eyes of the damsel flies are smaller than those of the dragonflies and are set wide apart on the sides of the broad head (giving an overall shape similar to that of a hammerhead shark). The large number of facets in the compound eyes of both sub-orders makes them very sensitive to external movements, allowing the insects to see and catch small insects in flight.


Dragonfly
Indigo Dropwing - female


Dragonfly
Indigo Dropwing - male


The colours of dragonflies are produced by pigments and/or structural effects, and are some of the most striking of the animal kingdom. The females frequently differ in colour or pattern to the males, and sometimes the colours change as the insects get older. An interesting feature of several species is a gradual development of a powdery bloom on the surface of older individuals, particularly the males, and this bloom may be whitish or powdery blue, which can completely alter the appearance of individuals in two or three days. These changes in colour between the sexes and ages can make species identification rather testing, particularly if you are as new to the task as I am!

Dragonfly
Common Darter - male

Dragonflies spend the early part of their lives in water, the majority of species favouring ponds or slow moving streams. All damsel flies and some dragonflies lay their eggs in or on water plants, putting their abdomens below the water surface to make contact with the plant (the ovipositor makes a slit in the plant tissue and the eggs are inserted). Most dragonflies simply scatter their eggs by skimming over the water and dipping the tip of the abdomen into the water, the eggs then slowly sinking into the stream or pond substrate. It is easy to watch them use this technique to deposit their eggs on still water bodies.



Dragonfly
Slender Skimmer - male
(Note: this species occurs only on Cyprus and Rhodes)



The eggs hatch into nymphs (the larval stage), and subsequent development of the wings and the compound eyes gradually takes place.The duration of the nymph stage depends on water temperature and food availability, but nearly all damsel flies complete their life cycle within one year. In the UK, however, the dragonfly life cycle can take between one to five years, and can require 10-15 moults during the nymph stage, but in Cyprus I would imagine that the life cycle is generally completed within two years.


Dragonfly
Violet Dropwing - female



Dragonfly
Violet Dropwing - male


The basic wing structure and venation is the same for both sub-orders. Towards the tip of the wings there is a dark area, called the pterostigma (or just stigma), and the colour of this cell is species specific, and generally helpful for identification. Some of the larger dragonfly species will fly considerable distances away from any water in their hunt for their insect prey, but all are dependent on water to complete their life cycle. The larger dragonflies will often have an established territory along a river or pond bank that the insect regularly patrols backwards and forwards for long periods.


Damsel flies are very slender and delicate insects with weak powers of flight, movement being more of a silent drift from reed to reed. They are usually found resting on waterside vegetation, as the following photographs illustrate.

Damsel fly
Common Bluetail (female) 


Damsel fly
Blue-eye (male) 

Damsel fly
Small Bluetail (male)

Damsel fly  
Common Bluetails mating



All Photographs by Trevor Fordham.  5 July 2020















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