Search This Blog

Labels

Saturday, October 8, 2016

the red dragonfly sighted at Hale Kiranguru - Karnataka

Our school days were lost without our understanding many things – remember this English poem of William Wordsworth (1770 – 1850), an English romantic poet whose magnum opus is considered to be ‘the Prelude’ : this was ‘butterfly’


I'VE watched you now a full half-hour;
Self-poised upon that yellow flower
.. .. .. ..
I know not if you sleep or feed.
How motionless!--not frozen seas

The opening lines  reveals his apparent entrancement.  It  perhaps was no poem on a simple butterfly, but more of what it could represent ! It's fragile, delicate, short lifespan and every moment could be it's last, with all the "predators" out there.  Though we take solace planning longer things, our life too is fragile…

Not as attractive is the one that we see generally when it is cloudy and about to rain – a  dragonfly,  an insect belonging to the order Odonata, having hindwing broader than front wing. Adult dragonflies are characterized by large multifaceted eyes, two pairs of strong transparent wings, sometimes with coloured patches and an elongated body. Dragonflies are agile fliers, while damselflies have a weaker, fluttery flight.  Have seen blue, green and black dragonflies – not red ones. 


Dragonflies are predators, both in their aquatic larval stage, when they are known as nymphs or naiads, and as adults. Several years of their lives are spent as nymphs living in fresh water; the adults may be on the wing for just a few days or weeks. Found nearer water bodies, they  have a uniquely complex mode of reproduction involving indirect insemination, delayed fertilization, and sperm competition.   Adult  dragonflies eat other insects and can consume hundreds of mosquitoes in one day! They are valued predators, since they help control populations of harmful insects. Dragonflies are usually found around lakes, ponds, streams and wetlands because their larvae, known as "nymphs", are aquatic. Adult dragonflies do not bite or sting humans, though nymphs are capable of delivering a painful but harmless bite.



Loss of wetland habitat threatens dragonfly populations around the world. Dragonflies are represented in human culture on artifacts such as pottery and paintings.   An article in NewYork times stated that one  research team has determined that the nervous system of a dragonfly displays an almost human capacity for selective attention, able to focus on a single prey as it flies amid a cloud of similarly fluttering insects, just as a guest at a party can attend to a friend's words while ignoring the background chatter. Other researchers have identified a kind of master circuit of 16 neurons that connect the dragonfly's brain to its flight motor centre in the thorax. With the aid of that neuronal package, a dragonfly can track a moving target, calculate a trajectory to intercept that target and subtly adjust its path as needed ... As a rule, the hunted remains clueless until it's all over.  That is more akin to a ‘stealth fighter craft’.

Dragonflies have two sets of wings with muscles in the thorax that can work each wing independently. This allows them to change the angle of each wing and practice superior agility in the air. Dragonflies can fly in any direction, including sideways and backward, and can hover in a single spot for a minute or more. This amazing ability is one factor in their success as aerial ambush predators — they can move in on unsuspecting prey from any direction. Not only are they agile, but they're fast, with some species reaching a top speed of 18 miles per hour. Dragonflies lay their eggs in water, and when the larvae hatch, they live underwater for up to two years. Actually, depending on the altitude and latitude, some species may stay in the larval state for up to six years !

On a trip to Thirunarayanapuram(Melukote) and then to the avathara sthalam of Sri Thirumalai Ananthalwar, Hale Kiranguru near Sri Rangapatna, nearer the small beautiful pond, saw some ‘red dragonflies’ – which is the subject matter of the post.

Understand that the  red-veined darter or nomad  is a dragonfly of the genus Sympetrum. It is a common species in southern Europeand from the 1990s. Males have a red abdomen, wings have red veins.   and the wing bases of the hind-wings are yellow. The pterostigma are pale  - they reportedly could be found in Europe, regions of the Middle East and some regions of southwestern Asia like Sri-Lanka, India, and Mongolia. 

May not be most exotic, yet this one was quite attractive !

With regards – S. Sampathkumar

8th Oct 2o16.

No comments:

Post a Comment