Dragonflies - at look at Cheshire's ancient creatures
PUBLISHED: 11:50 13 September 2012 | UPDATED: 21:51 20 February 2013
Few creatures can claim to have shared the earth with dinosaurs, but dragonflies were in the thick of the action then, just as they are today, as Cheshire Wildlife Trust's Tom Marshall reports
When you think of wildlife that can survive whatever cataclysmic event put an end to the dinosaurs rule, its a pretty tough bunch that springs to mind sharks, alligators and other deep-sea dwellers far beyond our view. But believe it or not, one of our most delicate insects, the dragonflies, were also sharing the skies with pterodactyls albeit a little larger than the ones you may find in your garden this summer.
The prehistoric ancestors of todays dragonflies and damselflies in fact had a wingspan in excess of two feet, with a weight heading towards half a kilo aided by around 10-15 per cent more oxygen in the atmosphere than were used to nowadays. While these hawk-sized Meganeura were a force to be reckoned with, our own dragonflies remain a voracious and feared predator of the pond.
Dragonflies are still one of our largest insects, however the worlds heaviest insect today, the goliath beetle, only weighs in at around a quarter of the weight of dragonflies of the dinosaur age. By comparison, modern dragonflies have a wingspan of no more than 19cm and are carrying a lighter load of just a few grams.
Although most of us are familiar with the colourful and vibrant adult dragonflies patrolling our hedgerows and lake edges, its the early underwater phase of the dragonflys life where it carries its most fearsome reputation.
For anything from a few months to five years, larval or nymph dragonflies stalk the murky depths of our waterways in search of a meal and anything that is unlucky enough to swim past can end up on the menu, from unsuspecting small fish to tadpoles. Extendable mouthparts that have been likened to the aliens of Steven Spielbergs cinematic imagination only add to the trepidation for those unlucky enough to pluck one out of a pond for closer inspection.
Eventually though the time comes to realise their true calling, and over just minutes or perhaps an hour or more, the larvae climb up into nearby vegetation and breath air for the first time, simultaneously releasing their powerful wings to dry in the sun in readiness for a maiden flight. After so long ruling the depths, these teneral dragonflies and damselflies find themselves at perhaps the most vulnerable they have ever been, with neither the safety of water or the strength and prowess of flight to rely upon.
Finally they must make a leap of faith and head out across the water and their dazzling colours and buzzing sorties is how most of us will recognise these aerial acrobats.
We can get a glimpse of the blue and green hues in the air, but the dragonflys true beauty is best appreciated when they are at rest. From the azure blues and blood-reds of the damselflies, to the yellow and black of the clubtail dragonfly its no surprise they were once known as the devils darning needles.
Ferocious predators of other flying insects, their speed and superb vision enable them to catch mosquitoes, flies, bees, butterflies and even smaller dragonflies, making them no less capable than during their time under the water. With the unpredictable British summer to contend with its often a case of eating-on-the-go for many dragonflies, with some of our larger hawkers known to carry prey around in a cage of their legs underneath.
Dragonflies dont get to chalk up many flying hours though, and the two months that many of them are on the wing is the final flourishing fraction of their overall lifecycle.
With such speed, accuracy and agility in the air, there are few who can match dragonflies in the top-gun stakes, however a summer visitor from Africa, the hobby, has made dragonflies its personal delicacy.
These moustached and handsomely-marked falcons take up summer residence wherever dragonflies hang out, using all their skill to pick-off them off, imitating the on-the-go approach of their prey, quickly despatching of the low-value wings and devouring the rest in mid-flight.
In late summer across some of our larger wetlands, mosses and heathlands its not uncommon to find more than a dozen hobbies feeding together in the same area.