A major article by John Solomon, August 2020
A guide to the ODONATA of the ANDOVER region.
Introduction
Odonata is the Latin term for the insects more commonly known as Damselflies and Dragonflies. While superficially very similar they do differ in several ways. Firstly, Dragonflies are larger than Damselflies and when they rest they always do so with their wings stretched out from the body. The nymphs, the immature forms that live in rivers, streams, lakes and ponds, add another major difference in the positioning of the gills they use to breathe. Damselflies have three feathery gills, known as caudal lamellae, attached to the end of their abdomen. Dragonfly nymphs, on the other hand, have their gills inside their abdomen, actually taking water in and then expelling it through the rectum. If necessity demands they can eject this water very forcibly to give them a short burst of speed, perhaps to escape a predatory fish.
Being insects all Odonata larvae have six legs, an exoskeleton with wing buds and a hinged jaw. A characteristic of this is the extendable lower lip, or labium. This mask consists of two connected parts and a pair of labial palms, these end in thorns which are used to grab the prey. In resting state the mask is held under the head and covers the mandibles, but when striking prey the mask is extended by a contraction of muscles and bodily fluids, greatly increasing the reach. This strike can happen in as little as 25 milliseconds and enables the nymph to catch and kill prey even larger than itself. It was this that provided the inspiration for the Alien in the movies of the same name. While young nymphs might feed upon small water insects such as Water Fleas more mature and larger nymphs might take on small fish, tadpoles and even newts. They live in submerged vegetation, or even down in the silt and sediment at the bottom of bodies of water, and are prodigious hunters.
As insects they cannot grow by simply getting larger, their exoskeleton prevents that, so at regular intervals they shed the exoskeleton they have replacing it with a new one a size larger. The smaller Damselflies will go through 5 such moults but the larger Dragonflies might moult as many as 14 or 15 times. Similarly, the larger the insect the longer it takes for it to feed up and reach the state of emergence. The Common Emerald Damselfly lays its eggs towards the end of Summer and they do not hatch until early the following Spring. The larva then feed voraciously, emerging only 3 months or so later as adults, but this is exceptional. Most Damselflies take 1-2 years to reach the point where they are ready to leave the water and take to the sky, although this is dependent upon the availability of food. Larger Dragonflies, such the Golden-Ringed, can remain as nymphs and feeding up for as long as 5 or 6 years.
The timing of the emergence the insect is decided by the nymph being fully grown, but also the length of daylight and the temperature. When the insect decides the time is right it climbs up out of the water, often using a reed. The exoskeleton of the nymphs splits and the adult insect starts to push itself out. It pauses once the head, thorax and legs are free, waiting for half an hour or so to allow the fresh and soft new exoskeleton to harden. Once the legs are firm it then hauls out the abdomen. By pumping fluids around the body and through the veins of the wings the abdomen is extended and the wings reach out into their full glory. The fluids are then drawn back into the body and the wings and exoskeleton allowed to dry and set. This is a crucial period in the insect’s life. Not only is it intensely vulnerable to any predator but if the expansion of the wings is compromised, for instance by being restricted by vegetation, then the wings will not form properly and it will not be able to fly … and if it cannot fly it cannot catch prey and feed.
They leave behind the empty shell, or exoskeleton of the nymph they have been through their water-bound phase, known as an exuviae. These can often be found still attached to reeds around the water margins. This is the exuviae of a Migrant Hawker:
The newly emerged adult, or teneral, may not necessarily have its full adult colouration and patterning. Dragonflies are often pale green while the Damselflies offer a variety of different colours, the female Blue-Tailed Damselfly being an excellent example, and the insect may take around a week before the full, adult pigmentation is seen. This can make identification interesting.
With wings dry the insect now heads skyward to take its place as one of the most deadly predators on Earth. Their hunting success rate has been estimated at 95%, so if you are a small flying insect and a Dragonfly or Damselfly decides that you are lunch, then you are truly lunch. They owe their devastating prowess in part to their four magnificent wings. They can operate all of them independently through a wide range of movement, enabling them not only to fly forwards, upwards or sideways but also to hover and even fly backwards. Furthermore, they are able to execute a change in direction at blinding speed. To guide this amazing flying ability and pinpoint their prey they have remarkable vision. All insects use what are known as compound eyes, being formed of a series of what are effectively tubes, known as facets or ommatidia. These contain light sensitive proteins, or opsins, which respond to different wavelengths of light. In the case of Dragonflies and Damselflies there four or five different opsins enabling them to see beyond our own spectrum and into such optical regions as ultra violet. Each eye can contain up to 30,000 of these ommatidia and, thanks to their round structure, the two eyes give them a fully spherical field of vision. Last, but not least, careful examination of those 6 legs will reveal what look like hairs or bristles, but they are not. Instead they are stiff, hard spikes of the chitin that forms the insect’s exoskeleton. When it attacks its prey it wraps them up in its legs, which form a cage known as the basket, and those spikes help hold it secure. Damselflies and Dragonflies really are the dragons of the insect world. Unsurprisingly, the choice of prey will depend on the size of the insect. Damselflies will take smaller flying bugs and beetles but the Dragonflies, especially the larger ones, will take anything and everything, from smaller prey right up to butterflies, bees and other Odonata, including Damselflies!
As adults their main aim in life is to breed. To this end male Dragonflies will often commandeer a stretch of bank or reed bed which they will patrol relentlessly, investigating any intruder. They will drive away possible rivals but the insect will endeavour to mate with any suitable female that passes through, often quite forcibly. Damselfly species found in the area are not so territorial, mainly living in large groups throughout the reed beds around the local lakes, although the males are just as bent on fulfilling their obligations. The weather can be conducive, or otherwise. The hot early summer of 2018 filled the reeds and even the air with courting couples, while the rather lower temperatures and gustier wind of the same period a year later, in 2019, saw a much lower level of activity.
Male Odonata have two sets of sexual organs with the primary sperm producing organs situated at the very base of the abdomen. The insect transfers sperm from here into what might be thought of as a pouch on the underside of the second section, known as the ‘accessory genitalia’. During mating the male holds the female by the back of the neck using the claspers at the very tail end of his abdomen. If the female is agreeable she then reaches the tip of her own abdomen forward and up, so it meets the male’s accessory genitalia, and the sperm is transferred. This position is technically known as in copula and more commonly described as ‘the wheel’, although any observer will see from the shape the insects form that perhaps the term ‘the heart’ would be more fitting in more ways than one. The length of time the partners remain in this position varies considerably and has little to do with the size of the insects. The Blue-Tailed Damselfly is one of our smallest but the pair may remain attached to each other for up to 6 hours, while in the Chasers it lasts only a few seconds and can even take place in a brief mid-air encounter.
The fertilised female will spend most of her adult life engaged in laying eggs. Most species lay their eggs in floating or emergent vegetation, sometimes depositing them directly into the water but more often using a needle-like ovipositor to inject them into plant stems. A Damselfly will lay hundreds of eggs during the 2-4 weeks of her life and a Dragonfly, which may live for couple of months, could lay thousands. To give an idea a Banded Demoiselle was observed laying 450 eggs in one 45 minute session, while another unidentified Dragonfly was seen hovering over Rooksbury Lake laying at the rate of one a second for 7 or 8 minutes, giving a total of between 420 and 480 eggs. Normally the eggs hatch within 2-5 weeks although, as mentioned above, some species, such as the Common Emerald as well as some Hawkers and Darters, wait until the following Spring.
The egg-laying process is often a solitary thing for the female, but not always. It is common to see Damselfly pairs, locked together by the male’s claspers, flying low over the water in tandem. The male is the insect on top, carrying the female from egg-laying site to egg-laying site whilst keeping a lookout for anything threatening. Occasionally you might find a place that is popular for the activity and it can be surreal to see twenty, thirty, forty or even more pairs gathered closely en masse, the females down on the floating vegetation and laying while the males, attached to them, hover above. Although Dragonfly pairs will be seen flying in tandem this is not at the egg-laying phase but earlier in the courtship, as the male seeks a safe perch for them to complete the fertilisation. Once the deed is done it is very normal for the male to simply fly off into the blue yonder in search of another conquest, however, just occasionally he will stay with the female. I have watched this at Rooksbury, a female Emperor Dragonfly down on the floating debris and laying as her male hovers a yard or so over her offering protection. On this occasion I saw him drive away another male, a would-be suitor, so as to ensure it was his progeny that she injected into the floating stems.
Parasites
Parasites are one of the most diverse groups of fauna infecting virtually every organism on the planet. As such they are a significant evolutionary force, influencing genetic diversity and affecting not only individuals but entire species. In the Odonata these are mainly Gregarines and Water Mite larvae with studies finding that individuals often suffer from an infestation of both. Damselfly females tend to be far more vulnerable to ectoparasites than males, but there was no difference between the sexes in Dragonflies. Territorial and larger species, which mainly means Dragonflies, also seem to have far less susceptibility than smaller species, mainly the Damselflies. This might, perhaps, be reflected in a greater annual variation in the numbers of individuals counted. When the insect numbers are high this provides a ready feast for any parasites, resulting in a rapid growth in their numbers. This profusion means that the numbers of the host species are driven down, making life harder for the parasitic species and causing their numbers to fall. The drop in numbers then makes it easier for the host species to proliferate, which results in a rapid growth of their numbers in turn. Then the cycle starts again running over several years.
Gregarines
Endoparasites, these are a group of Apicomplexan alveolate, classified as Gregarnasina or Gregarinia. They are large for Protozoans, roughly half a millimetre in length, and inhabit the intestines of many invertebrates, including Odonata, but are not found in vertebrates. They are usually transmitted by the orofaecal route but some may be passed from one individual to another during copulation.
Water Mite Larva
These are what are known as ectoparasites. The vast majority of Water Mite larva are parasites of aquatic insects, including Odonata larvae, the mite young attaching themselves to the underside of mainly the thorax and occasionally the forward sections of the abdomen of the nymph. Some species of nymph can resist infestation by what is known as melanotic encapsulation, by which the mite’s stylestome, or effectively the feeding tube, is blocked and the larva starves to death.
Damselflies
Dragonflies and Damselflies are insects, which means that, in basic terms, their bodies are formed of three sections. Their head, which is self-explanatory, holding those over-sized eyes, the crushing jaws and a pair of very small antennae. The mid-section is a large and solid box, known as the thorax, which has the wings on its upper surface, holds the powerful flight muscles, having the under-carriage of the legs underneath. The third section is visually its tail, stretching out long and slender behind the insect, but is in fact the abdomen. In the Andover area there are two species of Demoiselle and seven of Damselfly. While the Demoiselles are reasonably easy to tell apart the Damselflies often have a blue male and a green female. It is only the careful study of the different colours, and sometimes very slight and subtle variations in the patterns of the markings, which enable differentiation. For identification it is also important to remember that the long abdomen is formed of ten sections. As mentioned above the male has accessory genitalia. This is effectively a bag seen as a small bulge found on the underside of section 2, just behind the thorax. In the descriptions that follow there will often be references to sections 8, 9 and 10, the end of abdomen’s “tail”, where some of the minor but important differences between species can be found.
As a general rule Damselflies emerge earlier than Dragonflies and that is certainly so for the species found locally. They will start to be found in small numbers towards the end of May, rapidly growing the populations through June and into July, then gradually disappearing through August. We start with the Demoiselles.
Demoiselles
The two species of Demoiselle found in the UK are the Banded Demoiselle and the Beautiful Demoiselle. Both like moving water and when they are found around standing water there will always be running water nearby. They love the chalk streams that run throughout the Test Valley and can also be found all along the Test itself. They emerge fairly early in the season and certainly you will begin to find them on the wing by mid-May. Most numerous through June and into July their numbers begin to drop off as you move through the month and into August.
They are metallic looking insects of medium size with a noticeably fluttering flight, often seen among reeds. The males like to find a spot at the water’s edge where they will establish a vantage point on a chosen reed and wait for a female to fly by. From here they will often dart out off their perch to chase other males away. In thick reed beds they seem more tolerant of each other, but the male will still like his chosen reed and expect others to keep away.
Banded Demoiselle
The commonest, one might say ubiquitous to the area, is the Banded Demoiselle:
The male:
The female:
Easily identifiable the male has a dark “thumb print” on its forewings. The female has pale green translucent wings with a “false white spot” towards the tip.
They can be found throughout the Andover area but are particularly prevalent at Rooksbury Lakes, which has a small network of streams running through it, also on Cow Common at Chilbolton. However, anywhere you are able to reach the reed beds at the side of the streams throughout the Test Valley you are going to find these.
Beautiful Demoiselle
The second Demoiselle species, the Beautiful Demoiselle, is far less numerous:
The male:
The female:
The male is immediately different to the Banded as the forewing is completely dark. I have read this described as a brown-black but, to me, it seems more a deep, inky blue-black. At first glance the female seems little different to the Banded Demoiselle female above and, in the wild, they can be difficult to tell apart. The thorax and abdomen are much the same colour but the wings are actually a translucent brown instead of green. Sometimes the sun will catch the insect at just the right angle and then she becomes lit up as a surprising gold. The one way to be sure, unless you are lucky enough to stumble across a mating pair, is a reasonable photograph. Even if the colouration isn’t clear from this you will be able to see that the “false white spot” of this species is not quite as far along the wing, being a little further away from the tip, in comparison to the Banded female. This species can be found at Rooksbury and at Longparish, but the numbers are always rather low and always by the streams that run through. It is doubtless present along the length of the Test Valley, but access is severely limited so its exact distribution is not clear.
Moving on to the Damselflies themselves, unsurprisingly, the country’s four most common species are all present and correct, namely the Common Blue, the Azure, Blue Tailed and Red Eyed. All four are easily found around the three local lakes, but the first three also cope with moving water, particularly the small streams and gutters that are liberally spread throughout the water meadows of the Test Valley. The adults begin to emerge in May, although all three continue to hatch throughout the summer months, keeping a presence until the season draws to a close. The adults will usually live for around 2 to 4 weeks, although some individuals will be lucky enough to be on the wing for rather longer.
When these Damselflies first emerge they have very little colour, being an off-white, but this gradually becomes a browner hue. This is a female Common Blue:
At this stage of its life the insect is described as teneral. Over the next few days the insect will normally adopt its adult colouration.
Common Blue Damselfly
The Blue Tailed female manages to confuse matters so we will stay with the Common Blue Damselfly:
The male:
The female:
The male is always the electric blue colour but the female comes in two forms, blue, looking almost identical to the male, and green. However, the two can be easily told apart by a rapid examination of the “tail” of the abdomen:
The male:
The female:
As can be seen the male has the blue colouration wrapping boldly around sections 8 and 9, while in the female it is broken and concentrated where the sections meet. As the name suggests these are very common insects and can often be seen as mating pairs on reeds and other foliage, and also flying locked in tandem as the female lays eggs into floating vegetation.
Azure Damselfly
The Azure Damselfly is very similar in appearance to the Common Blue:
The male:
The female:
As with the Common Blue Damselfly the female occurs in both blue and green forms and, again, the same broken “tail” colouration can be seen in the female as with the Common Blue, allowing the differentiation of the two sexes. As can also be seen, these two species are very similar. There are several ways of telling them apart, but with all of them either a very close view or a reasonable photograph is necessary. The first is known as the Coenagrion Spur. This is a black marking, almost like a finger, protruding into the thorax colour of both sexes although I show it here on the male:
Common:
Azure:
The next is a marking on the top surface of the second abdominal segment. If you examine the above photos and look at the upper surface of the second abdominal segment you will find the second difference between the two species. The male Azure Damselfly has a clear black marking looking approximating the lower three sides of a rectangle. This is commonly termed the “beer glass”. On the other hand the male Common Blue has a smaller marking looking almost like a child’s drawing of a silhouette of a round tree.
The females, similarly, have a different marking on the top surface of this segment:
Common:
Azure:
In the Azure this almost a wine glass shape while the Common Blue female has a much more robust slab of black.
The third difference applies only to the males and is found right at the end of the tail of the abdomen. This can be seen in the lower black circle marked on the above photos. The Common Blue has solid colour wrapping around sections 8 and 9, whereas in the Azure male this is broken by an obvious intrusion of black on section 9. In the field this often the easiest identifier to see. The mark on section 2 can be hidden when the insects land as they usually lay their wings along their length, hiding it, and the Coenagrion Spur requires a good close up view of the side of the thorax.
Blue Tailed Damselfly
This leads us to the most confusing of the commonest Damselfly, namely, the Blue Tailed. The male is simple enough. After emerging he first assumes his immature colouration:
As can be seen the thorax is green and the blue tip of the “tail”, the reason for its name, is very clear. Careful examination of the underside of the second section of the long abdomen will reveal a small bulge, being the accessory genitalia. This is the adult colouration:
So far, so straight forward, but the female adopts an array of different colours depending on not just maturity but also simple colour variations. She has two immature forms. The first is known as violacea:
This very attractive lilac form then changes to either of two adult forms. The first is typica:
This particular example still has a trace of immature lilac on the thorax but the similarity to the male is very clear, that is why a good photograph is desirable. Examination of the second abdominal section is required, checking out whether the male’s accessory genitalia are present, to establish exactly what the insect is. The other possible colouration for the violacea form to mature into is known as infuscans:
The second immature form of the female is rufescens:
As this example shows in a young and fresh insect the thorax can be a very striking raspberry colour. This insect matures, the thorax going through a more adobe colour, gradually assuming a golden brown colour known as rufescens obsoleta:
Red Eyed Damselfly
The last of the four species is the Red Eyed Damselfly. This is more strictly a still water species, preferring ponds and lakes, especially those with a healthy reed growth, but it can also be found along canals and very sluggish rivers.
This is the male:
Notice the obviously red eyes and the Coenagrion Spur, which can occasionally finish in a detached “full stop”, but there is another visual clue which is helpful if you are more than a few yards away. This is that the insect has no shoulder stripes running down along the upper side of the thorax. These are known as the antehumeral stripes and their absence can make it look almost as if the Damselfly is wearing a “Batman” style cloak:
The female is green and very similar to the Azure female, having the same Coenagrion Spur on the side of her thorax. The eyes do have a reddish upper surface but it is nowhere near as noticeable as the burgundy-red of the male:
The tell-tale for this species is, again, the antehumeral stripes. The female does have them but they are short, often only running a third of the way back along the thorax:
This particular specimen is an absolutely text book example, which is why I have used it, but I have come across others where the cut-off of the antehumeral stripes is nowhere near as clear, and even others where there is a very thin a wispy vestigial stripe running most of the length of the thorax.
If you are very lucky you might come across a Damselfly that looks like a female but the antehumeral stripes are missing and the insect seems to be a rather paler green, almost a yellowy colour:
This is an immature male Red Eyed and it will take him a day or so to assume his electric-blue adult colouration.
Small Red Eyed Damselfly
There is one more “blue” Damselfly found in the area but it has only been reliably seen and recorded on film once, on 25 July 2017, at Charlton Lake. This is the Small Red Eyed Damselfly. It is nowhere near as common as the Red Eyed, only beginning to colonise this country in July 1999. Its flying season is later than the Red Eyed, beginning in the second half of July and stretching through August, so a sighting of a possible insect at the beginning of June will be the Red Eyed. It favours still waters with plenty of floating or emergent vegetation over which it will fly, mate and sunbathe, making it difficult to photograph as it will usually be well away from the bank. I feel they could well be present on Anton Lake, at the town end, as there is plenty of emergent vegetation there, but to find out would require access to a boat which I don’t have! This is a mating pair:
As can be seen the similarity with the rather commoner Red Eyed is obvious and the two species are virtually impossible to tell apart without a reasonable photo. With this species, too, the Coenagrian Spur often finishes in a “full stop”. The differences between the two species are very small indeed and to try and show them I am first going to zoom in on the above photo:
This shows that the female has a complete and strong antehumeral stripe, and that the male has a small break in the blue band around section 10. These are the only immediately obvious identifying features.
Large Red Damselfly
This completes the “blue” Damselflies in the area but there are two other species resident. The first I shall look at is the Large Red Damselfly. These are widespread and common, according to the book, but they are nothing like as ubiquitous as such a description would lead you to believe. Like the first three Damselflies, Common Blue, Azure and Blue Tailed, they are not too fussy about their environment, being found both on still water and small streams and gutters. They like the presence of reeds and other emergent vegetation and perhaps that explains why they don’t seem to be present on Charlton Lake or at Rooksbury.
The male:
The female:
They are easy to tell apart by looking at the abdominal sections:
The male:
The female:
As can be see the male has only a red band circling the joining of the sections and broader red bands at the junctions of the last four. The female has yellow banding as well. The female variation shown is the commonest, being known as typica. She comes in two other forms. One has barely any of the blackness on section 6, being known as fulvipes, while the other has the blackness extending all the way up the abdomen and is called melanotum. Personally, I have so far only seen typica in this area … watch this space!
Common Emerald Damselfly
The last Damselfly known to be in the area is the elusive Common Emerald:
The male:
The female:
Apologies for the softness of the female photo, she was being blown around by the wind. This mating pair shows her more clearly:
These have only been found at Anton Lake, in what is known as the Tench Pond at the town end of the lake. Another species annoyingly described as widespread and common it is on the wing later in the summer, through July and August. It is not a robust insect or a strong flyer and it is only found where there is still water, preferring ponds or parts of lakes where there are thick reed beds in which it can tuck itself away. This makes it a tricky customer to see properly or photograph, the females being particularly shy. In fact the photo above of the female is very third rate compared to what I consider acceptable and I wouldn’t normally use it, except that it is the only one I have.
This Damselfly has a very different life cycle to others which usually lay their eggs, in submerged stems or debris floating on the surface, through the spring and summer. They then hatch and the nymphs feed up over the next 9 months or so to then emerge as adults the following year. The Emerald female lays her eggs in the stems of the reeds and other emergent vegetation towards the end of summer. Often they will not be laid below water level but may be deposited quite far up the stem, I have even watched a female injecting them into plant tissue near the top of tall reeds. The eggs don’t hatch until the following spring, the prolarvae wriggling out and, if necessary, dropping down into the water. As with all other species of Odonata the prolarva quickly sheds its skin and then starts hunting and eating. Common Emerald nymphs are voracious, and they have to be. In as little as two or three months they must feed up and reach the stage of being mature nymphs ready to take to the air as adults.
The fact that they over-winter as eggs means the Damselfly can colonise and inhabit smaller ponds which might dry up as the summer progresses. That is not a problem for them as the ponds will fill with water over the wetter winter months ready for the young to hatch from the eggs in spring. It also brings with it the added benefit of removing any predators.
I include one more photograph. Identification of this species in the field is made a lot easier by the position it assumes when sitting. Other Damselflies habitually sit with their wings either folded along the length of the abdomen, or else with them held out horizontally at right angles to it. The Common Emerald, very distinctively, holds its wings in a delta formation:
This is very noticeable, even from several yards away and, helpfully, both sexes do this.
This concludes the section on the Damselflies in the Andover area, now let us move on to the Dragons!
Dragonflies
Dragonflies are larger than Damselflies and always rest with their wings held out horizontally from the thorax. Many of them are relatively large insects with powerful flight enabling them to easily travel significant distances. Upon emerging and taking to the air they will often leave the lake, pond or river where they spent their nymph stage of development to be found coursing woodland paths and rides. The smallest members of this family are the Darters.
Darters
Common Darter
The sole local representative is the Common Darter. Both sexes of this species emerge and first adopt a yellow colouration:
The male:
The female:
Apologies for the not entirely sharp quality of the male! The two insects look very similar at this stage of their lives, but don’t worry, they know the difference! To us the easiest to see is that the female has a clear rectangular panel in the middle of the side of the thorax, as circled. After a few days the insects take on their adult colouration:
The male:
The female:
The male adopts a strong red colour with two very clear yellow, diagonal stripes on the side of the thorax. These markings will delineate it clearly from the very similar Ruddy in areas where they are both found … not here, as mentioned above only the Common Darter is found locally. The female turns a grey-brown colour and as she ages displays a blueish pruinescence along the underside of her abdomen. The species is very common around the local lakes, preferring still water, but occasionally being found along rivers and streams in the area. They like to adopt a perch on an outstanding stick, twig or other vantage point from where they will ‘dart’ out to take prey, then often returning to the same place, hence the name.
Chasers
Broad Bodied Chaser
There are two species of Chaser found around Andover but it is believed only one is actually resident. This is the Broad Bodied Chaser:
The male:
The female:
These are very much creatures of the lakes and ponds and are often the first Dragonfly to colonise a new body of water. They are one of the earliest on the wing being found in May through to July and often far away from water. Locally they are seen at Charlton and Anton lakes but also at Harewood Forest where they will cruise the clearings looking for small flying insects to devour. The female is often nicknamed the Hornet Dragonfly because of her and, in flight, the similarity is very clear. The golden filigree at the base of the wings is fairly typical of the Chasers but tends to fade with age. The female shown is young and the colours are strong and vibrant. Below is a photograph of another much older female, this time taken on 7 July 2018:
As can be seen the difference is remarkable to the point where you would not think they were the same species of insect.
Four Spotted Chaser
The second Chaser found here is the Four Spotted Chaser:
The one shown is a male but the female is almost identical. I have circled the claspers at the end of the abdomen and, as you can see, they curve slightly outwards. The claspers on the female are straight, otherwise the female’s abdomen is slightly stockier but the two insects are very similar. The only place they have been seen locally is the Tench Pond at the town end of Anton Lake.
Skimmers
Black Tailed Skimmer
There are only three Skimmers indigenous to this country, the Scarce, the Black Tailed and the Keeled, and locally we only have the Black Tailed … and I only have photos of the male. The first is that of an immature individual, which I include in spite of the fact that it is one of my earlier efforts and, therefore, rather unsharp, because this insect looks very different when newly emerged to the eventual adult colouration:
This is a mature male:
Again, this species of lakes and ponds but, especially when young, can be found well away from them. The youngster above was found out in the countryside near Longstock. The female is yellow with striking black markings, but not too dissimilar to the juvenile male:
As with the Darters their flight pattern matches their name. Like the Darters they have a tendency to find a perch they like from where they sally out ‘skimming’ low over the water, back and forth, back and forth until they return to their chosen vantage point.
Hawkers
Brown Hawker
These are the large and showy creatures that everybody thinks of when the term Dragonfly is mentioned. Showing no preference I shall go through them alphabetically, starting, therefore, with the Brown Hawker. I make no excuses here, I only have a female example in my photo-library, so here she is:
You are not missing too much. Just as with the Four Spotted Chaser the two sexes look very similar, the only giveaway being that the upper surface of the eye is blue in the male.
Their main flight months are July and August. These are insects of standing water and sometimes canals and very slow rivers where the water flow is negligible. In this area that means the lakes and we seem to be in a situation for this insect that is, hopefully, in the process of developing. For a good number of years the occasional one has been seen here and there, the thought being that these individuals were tourists visiting from some other site unknown. Then, in 2019, there were suddenly large numbers of them.It was extremely unlikely that all those insects were visitors. Insects don’t have access to the internet and so wouldn’t have read rave reviews and suddenly decided to visited Andover en masse. A possible and more reasonable explanation is that around three or four years ago, the approximate length of time it takes for the nymph of this species to feed up, a fertilised female came to the area and spent a few weeks dashing around the local lakes laying eggs. Since numbers have always been down to individual sightings it is unlikely that a gang descended on Andover so the most plausible explanation is that just one insect was involved. In 2020 sightings were back down to the occasional single specimen, which supports this hypothesis of colonisation. It will be interesting to see what the numbers are like in 2022-23.
Emperor Dragonfly
The Emperor is officially the largest native Dragonfly and the second largest in the World, although more of this later! It is one of the commonest species around Andover’s lakes, preferring still water although it will inhabit sluggish moving water such as canals and very slow flowing rivers.
The male:
The female:
At rest this species would not be confused with any other appearing locally as the green thorax and blue body of the male is very distinctive. The ultimate diagnostic feature is the clear black line that runs all the way down the upper surface of the abdomen. The female can be trickier to identify, but only in telling her from the male as she, too, has a the same clear black marking. Often she has a green abdomen, in which case the identification is straight forward, but equally she may have a blue body, as with this specimen, then the differentiation is more difficult. In real life it is clearer that the blue colouration is rather paler on the female than the male. This species is also fairly easy to identify in flight as it characteristically flies with the abdomen drooping slightly downwards behind it.
It is one of the first Hawkers on the wing, appearing as early as late May, although more usually early in June, and continuing to emerge through the summer months. Late insects may even be seen through September.
Golden Ringed
This striking insect is a creature of moving water, loving the rivers and streams of the Test Valley. These are found all around the area so the Dragonfly is widespread but never particularly numerous. They don’t often turn up on Charlton Lake but are regularly seen at Anton and Rooksbury, along the Anton River and, of course, the Test. When I described the Emperor Dragonfly, above, as our largest Dragonfly I said I would mention that again. For me this is arguably the largest Dragonfly. According to “the book” the abdomen of the Emperor runs between 66mm and 84mm, while the same measurement for the Golden Ringed is 77mm for the male and 83mm for the female. The length of each hindwing is 45-51 for the Emperor and 41-50mm for the Golden Ringed. In other words the size of these two insects is so similar, allowing for individual variations, that it is impossible to truly describe one as bigger or smaller than the other. It also seems to me that the Golden Ringed is slightly stockier than the Emperor. Whichever way you choose this is a beautiful thing.
The male:
The female:
This is also on the wing from the beginning of June and will continue to emerge through the summer, although gradually disappearing through September. While looking superficially similar the sexes are easily told apart by the examination of both ends of the abdomen. While the female is stocky around sections two and three the male is clearly waisted. Meanwhile, at the further end of the abdomen the female is straight while the male has clear swelling to the shape.
Migrant Hawker
This is probably the commonest Dragonfly around the local lakes. It is noticeably smaller than the Emperor and while the latter flies with its abdomen drooping this insect flies with the abdomen held slightly aloft.
The male:
The female:
At a glance this species can be confused with the Southern Hawker, but examination of the segment just on the top of the thorax, just behind where the wings join, reveals a clear “T” shape as circled on the male, which both sexes have. Don’t be fooled by the name, this species is very much resident although, as with a lot of British insects, their numbers are regularly bolstered by visitors from across the Channel. They are a later emerging insect, generally first taking to the air in August. Their exuviae, and the photo I have used earlier in this article is one such, can often be found hanging onto reeds around a foot or so out of the water. The Tench Pond at Anton Lake is an excellent hunting site for these. The freshly emerged insect will happily travel away from the lake for a while to adopt its adult colouration, and can turn up anywhere. As with many other Dragonflies the female is rarely seen, concentrating on egg-laying, but she may be heard as she lays her eggs into the stems of live reeds and other vegetation. Listen for the rustling and beating of her wings against the leaves. The male can be seen in numbers, especially around Anton and Rooksbury, patrolling a chosen territory and occasionally resting on reeds or even surrounding bushes. Often he will be unfazed by a curious human creeping over to take a good look at him or run off a few shots.
Southern Hawker
Not the commonest species locally but usually present, more so at Rooksbury and Anton Lakes than Charlton. This is another creature of the second half of the summer, emerging through July, but continuing to fly right through September, it is one of the last to finally give way to the chill of autumn.
The male:
The female:
As mentioned above there is a superficial resemblance to the Migrant Hawker, the visual clue is the two bold yellow markings on the front of the thorax. Called “the headlights” by Dragonfly spotters they are not only obvious when the insect lands but can also often be discerned in flight. The sexes can be more difficult. Like the Emperor, the female can have a green abdomen but all those I have seen have had a more bluish colour, very similar to the male. The answer lies in the second and third abdominal segments where, as with the Golden Ringed, the male is waisted while the female is stockier. Like the Migrant the freshly emerged insect can travel considerable distances from where they hatched to adopt adult colouration, and the female shown here was found on Danebury Hill Fort. Again, they prefer lakes, ponds and canals and the female lays her eggs into the stems of vegetation growing in the water, such as reeds. Listen for those wings beating in the vegetation next to you!
That completes the roundup of local species, 9 Damselflies, including two Demoiselles, and 9 Dragonflies, including 1 Darter, I Skimmer, and 2 Chasers. However, we are not so many miles from the south coast and South West area of England, which is the landing and colonisation area for species from Continental Europe, and it is always possible that something not on “the list” may turn up. Candidates include the Willow Emerald Damselfly, there is no reason why the Ruddy Darter might not find a home here and the Lesser Emperor Dragonfly has been recorded as far afield as Gloucester, Cornwall, the Isle of Man and even Orkney. Keep your eyes open, always have a camera with you and … good hunting!
Wildlife and Ecology, the Wildlife Encyclopaedia 