Meet the dragonfly, nature’s flying machine!https://indianexpress.com/article/parenting/learning/dragonfly-natures-flying-machine-5287850/

Meet the dragonfly, nature’s flying machine!

Large dragonflies, like hawkers, have a maximum speed of 10-15 metres per second (22–34 mph) with an average cruising speed of about 4.5 metres per second (10 mph). Dragonflies can fly at 100 body-lengths per second, and three lengths per second backwards.

dragonflies, dragonflies and damselfies, wildlife, environment
The tiny but mighty dragonfly (Source: Sohail Madan)

Did you know that dragonflies, which can slice through the air in a blur at super speeds, are older than dinosaurs? Or that there exists a cyborg-like genetically modified DragonflEye? To find out more, we asked environmentalist Sohail Madan, Centre Manager, Conservation Education Centre (CEC), Delhi to spill some beans at Asola Bhatti Wildlife Sanctuary, which is co-hosting the Dragonfly Festival with WWF-India, from August 3 to September 1, 2018.

Why do we need a dragonfly festival? In fact, why should we pay any attention to them at all?

Dragonflies and damselflies have been an integral part of urban biodiversity for a long time and till their habitat was safe and their numbers sufficient, they kept the population of disease causing mosquitoes to the minimum. With drastic changes in our city, the deadly cases of dengue and malaria are on the rise. To highlight all this and more, we have planned this festival around these lovely creatures. Moreover, they are also good indicators of clean and pure air and water.

How many different types of dragonflies exist in the world and in India?

About 3,012 species of dragonflies were known in 2010; these are classified into 348 genera in 11 families. India has about 500 recorded species.

CEC, Asola Bhatti
Environmentalist Sohail Madan

Do dragonflies predate dinosaurs?

Yes, the oldest recorded fossils are from over 300 million years ago, long before dinosaurs are known to have roamed the earth.

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What makes Indian dragonflies stand out from the rest of the animal kingdom?

They are very active predators of adult mosquitoes as well as their larva. Colloquially known as helicopters, they are some of the best fliers in the world. They even have the ability to fly backwards and most of their hunting happens in mid-air. They have very strong jaws; in fact, that is what gives them their scientific name Odonata (“toothed ones”).

Dragonflies are also known to be long-distance fliers. Can you tell us a little about that?

 

Dragonflies are powerful and agile fliers, capable of migrating across the sea, moving in any direction, and changing direction suddenly. In flight, the adult dragonfly can propel itself in six directions—upward, downward, forward, backward, to left and to right.

They have four different styles of flight and a number of flying modes are used that include counter-stroking, with forewings beating 180 degree out of phase with the hindwings, used for hovering and slow flight. This style is efficient and generates a large amount of lift; phased-stroking, with the hindwings beating 90 degree ahead of the forewings, is used for fast flight. This style creates more thrust, but less lift than counter-stroking; synchronised-stroking, with forewings and hindwings beating together, is used when changing direction rapidly, as it maximises thrust; and gliding, with the wings held out, is used in three situations—free gliding, for a few seconds in between bursts of powered flight; gliding in the updraft at the crest of a hill, effectively hovering by falling at the same speed as the updraft; and in certain dragonflies, such as darters, when “in cop” with a male, the female sometimes simply glides while the male pulls the pair along by beating his wings.

dragonflies
The Trumpet Tail male dragonfly or Acisoma panorpoides (Source: Nazneen Siddique)

Are there any weird and wonderful facts about dragonflies?

In general, large dragonflies like the hawkers have a maximum speed of 10–15 metres per second (22–34 mph) with average cruising speed of about 4.5 metres per second (10 mph). Dragonflies can fly at 100 body-lengths per second, and three lengths per second backwards.

The flight muscles need to be kept at a suitable temperature for the dragonfly to be able to fly. Being cold-blooded, they can raise their temperature by basking in the sun.

They are almost exclusively carnivorous, eating a wide variety of insects ranging from small midgets and mosquitoes to butterflies, moths, damselflies, and smaller dragonflies.

A dragonfly has been genetically modified with light-sensitive “steering neurons” in its nerve cord to create a cyborg-like “DragonflEye”. The neurons contain genes like those in the eye to make them sensitive to light. Miniature sensors, a computer chip and a solar panel were fitted in a “backpack” over the insect’s thorax in front of its wings. Light is sent down flexible light-pipes named optrodes from the backpack into the nerve cord to give steering commands to the insect. The result is a “micro-aerial vehicle that’s smaller, lighter and stealthier than anything else that’s manmade”.

dragonflies
The Orange-Tailed marsh dart, a male dragonfly, or Ceriagrion cerinorubellum (Source: Nazneen Siddique)

What makes dragonflies different from butterflies, moths and other insects in their family?

They have three life stages (egg, nymph, adult), which are different from moths and butterflies, which have four. The nymph of a dragonfly is an aquatic creature, breathing underwater and even using this breath to propel forwards in the water. These nymphs are also very long lived compared to other insects. Dragonflies have compound eyes and very good eyesight in comparison to the other insects.

Where can children spot dragonflies around them?

The best places to spot dragonflies are wetland habitats and forest areas. They prefer living close to water bodies as laying eggs happens in the water. In Delhi-NCR, the Okhla Bird Sanctuary and Asola Bhatti Wildlife Sanctuary are good spots to view them. The best season for watching them is monsoon.

How can kids learn more about them?

Come join the festival, there is programming available for all age groups. We will be distributing a brochure on identification of common dragonflies and showing movies on it. Apart from that, the Conservation Education Centre-Delhi runs regular programmes on them all year long.

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(For more information on the festival, email cecbnhsdelhi@bnhs.org or call 8800741864.)