Wiltshire Wildlife Trust looks at the dragonfly

PUBLISHED: 17:04 19 August 2010 | UPDATED: 17:44 20 February 2013

Wiltshire Wildlife Trust looks at the dragonfly

Wiltshire Wildlife Trust looks at the dragonfly

The dragonfly is a beautiful but ferocious predator, as Susan Litherland, from the Wiltshire Wildlife Trust, explains

Take a stroll near almost any stretch of water in the summer and you will see dragonflies performing elaborate aerobatics, their bright metallic colours glinting in the air. For us, these flying jewels are an integral part of summer, but to other insects the dragonflies are ferocious predators from the minute they hatch as aquatic larvae to their brief lives as flying adults. It is this mix of beauty and beastliness that is part of their fascination.

Dragonflies are an ancient order of insects that were hunting their prey before dinosaurs stalked the Earth. Delicate imprints of their fossilised remains (the oldest lived 300 million years ago) show they remain virtually unchanged. Today, dragonflies and damselflies are still widespread throughout the UK, and Wiltshire is home to 32 of about 56 species in the whole country. Collectively, they belong to the order of insects termed Odonata.

I love everything about dragonflies, says Steve Covey, the County Odonata Recorder and membership recruiter for the Wiltshire Wildlife Trust. I love their brilliant colours, and their life cycle is fascinating. At up to 30mph they are the fastest insects in the UK, and they can stop dead and turn on a sixpence, hover, fly backwards and sideways.
However, these complex creatures are threatened by habitat destruction and pollution; climate change is also having an impact, bringing new species into the UK from Europe, allowing species here to move further north, threatening the existence of others.

Two summers ago a visitor alerted Steve to the fact that there were Scarce Chaser Dragonflies at the Caen Hill locks in Devizes, the first time they had been recorded there. In the past, the canal has proved a poor breeding ground for dragonflies because the boats create turbulence, but Steve found newly emerged Scarce Chasers, so they had obviously been breeding nearby. Climate change will be at least partly behind their population expansion, he explains, because as temperatures increase dragonflies are able to use habitats that previously were unsuitable.


Wiltshires dragonfly atlas
With the help of the Wiltshire and Swindon Biological Records Centre (WSBRC), based at the Trust, Steve is recording and mapping the exact whereabouts of dragonflies and damselflies around the county to create a Wiltshire Dragonfly Atlas. This will act as a baseline against which future changes can be compared, and be used to monitor endangered species and help the Trust and other organisations make conservation decisions. The results will feed into a five-year programme run by the British Dragonfly Society to map the distribution of Odonata around the UK, which will culminate in the publication of a national dragonfly atlas in 2013.

There is still so much we dont know about these fascinating insects, including the detailed distribution of each species, says Steve. The lack of a long-term sustained recording effort means there are many gaps.
Yet the profile of Odonata is on the rise, and as dragonflies are temperature-sensitive, they are useful for climate-change studies. And as they Take a stroll near almost any stretch of water in the summer and you will see dragonflies performing elaborate aerobatics, their bright metallic colours glinting in the air. For us, these flying jewels are an integral part of summer, but to other insects the dragonflies are ferocious predators from the minute they hatch as aquatic larvae to their brief lives as flying adults. It is this mix of beauty and beastliness that is part of their fascination.

Dragonflies are an ancient order of insects that were hunting their prey beforedinosaurs stalked the Earth. Delicate imprints of their fossilised remains (the oldest lived 300 million years ago) show they remain virtually unchanged. Today, dragonflies and damselflies are still widespread throughout the UK, and Wiltshire is home to 32 of about 56 species in the whole country. Collectively, they belong to the order of insects termed Odonata.

I love everything about dragonflies, says Steve Covey, the County Odonata Recorder and membership recruiter for the Wiltshire Wildlife Trust. I love their brilliant colours, and their life cycle is fascinating. At up to 30mph they are the fastest insects in the UK, and they can stop dead and turn on a sixpence, hover, fly backwards and sideways.
However, these complex creatures are threatened by habitat destruction and pollution; climate change is also having an impact, bringing new species into the UK from Europe, allowing species here to move further north, threatening the existence of others.

Two summers ago a visitor alerted Steve to the fact that there were Scarce Chaser Dragonflies at the Caen Hill locks in Devizes, the first time they had been recorded there. In the past, the canal has proved a poor breeding ground for dragonflies because the boats create turbulence, but Steve found newly emerged Scarce Chasers, so they had obviously been breeding nearby. Climate change will be at least partly behind their population expansion, he explains, because as temperatures increase dragonflies are able to use habitats that previously were unsuitable.


Wiltshires dragonfly atlas
With the help of the Wiltshire and Swindon Biological Records Centre (WSBRC), based at the Trust, Steve is recording and mapping the exact whereabouts of dragonflies and damselflies around the county to create a Wiltshire Dragonfly Atlas. This will act as a baseline against which future changes can be compared, and be used to monitor endangered species and help the Trust and other organisations make conservation decisions. The results will feed into a five-year programme run by the British Dragonfly Society to map the distribution of Odonata around the UK, which will culminate in the publication of a national dragonfly atlas in 2013.

There is still so much we dont know about these fascinating insects, including the detailed distribution of each species, says Steve. The lack of a long-term sustained recording effort means there are many gaps.
Yet the profile of Odonata is on the rise, and as dragonflies are temperature-sensitive, they are useful for climate-change studies. And as they spend their lives both in water and out of it, they are indicators of the state of aquatic and terrestrial habitats.


Dragons, Damsels and Nymphs
The life cycles of dragons and damsels are similar. They spend the majority of their lives under water as larvae, and are only on the wing as adults for a brief instant, to breed, before dying. They are unusual in that they transform directly from larvae into adults, missing out the pupa stage common to most insects.


Females lay eggs in (or near) water, often on floating plants. After about two weeks the eggs hatch and a larva (or nymph) emerges, using internal gills to breathe. The larvae are the top predators in their freshwater world and will eat anything with a soft body that is smaller than themselves. Larger larvae will even tackle small fish such as sticklebacks.
The larvae are far less attractive than the mature insects, having tiny wings and a large lower lip, which contains a fearsome hinged jaw. They shoot their jaw forwards to impale their prey, which they then grind up with its serrated edges, says Steve.



Larvae moult seven to eight times, growing larger each time they shed their skins. For some species, such as the Red-veined Darter, this process can take less than a year; for others, like the Golden-ringed Dragonfly, it can take up to eight.
When ready to hatch, the larva will use its hooked feet to climb onto the stem of a nearby plant at night. Exposure to air causes the larva to begin breathing oxygen. The skin splits and the adult dragonfly crawls out, leaving its old larval skin (exuvia) behind. This is when the hunter becomes the hunted, and the first few hours of adult life are fraught with danger, as the soft body and crumpled wings leave them exposed and vulnerable and unable to move far,
I have seen the perfect husk of a dragonfly left at the top of a stalk. It only got that far before a spider paralysed it, sucked its juices out and left its empty shell behind, says Steve.
Other predators include birds and frogs. Wagtails and reed warblers, coots and moorhens will all snap them up, and hobbies feed on them during the summer before they switch to their autumn diet of swifts and swallows.

Deadly predators
When Odonata emerge, the males and females of most species usually start off a pale straw colour, which turns darker over a few days. Once up in the skies, dragonflies resume their natural role as top predators among insects. Their enormous eyes so big they take up most of their face are excellent for hunting, and when combined with their large jaws, they make a fearsome foe indeed.
Adult dragonflies even have bristled legs which they hold in a forwards scoop (like a baseball catchers glove) when they hunt, so that they can hoover up midges and other small insects as they fly. They will eat butterflies, other Odonata, in fact anything that is smaller than themselves.



By now the clock is ticking. Some remain on the wing for only a couple of weeks, while larger dragons can last for four months. Most dont get the chance as they die from accidents, predation and, if the weather is bad, from starvation. Time is of the essence if they are to mate and create the next generation.

The beautiful demoiselle will go to great lengths to attract a mate. The females settle into a bank-side view and the males, in their metallic blue-green armour, sit on adjacent vegetation or somewhat riskily float on the waters surface, energetically fluttering their indigo-coloured wings to tempt them into partnership. Once mated, female dragonflies use their ovipositors (the organs used to lay eggs) to attach their eggs. I have seen the Golden-ringed Dragonfly literally pogo-ing up and down in a stream to attach her eggs to the gravel on the bed, says Steve.

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