The flying aces of the insect world
Odonates are the solo exception among insects that can propel each of their four wings independently, which gives them the capability of extreme maneuverability, including sharp twist and turns and even flying backwards
Foring! The name unearths excitement, joy and adventure. Who can recall the childhood memories of tying up the insect to make it fly like a kite? Indeed, the vibrant flutterer did always throw challenges in chasing and catching pursuit of a kid.
They come with iridescent colours, large bulbous eyes, long, slender tails and strong veined wing-pairs. The insects that we lovingly call foring in Bangla are of a specialist and ancient flying order – the Odonata.
In layman's terms, they are recognized as dragonflies and damselflies.
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The first flyers
Odonates are the first among the insect kingdom to have conquered the aerial domain. Evolved in the Carboniferous era around 250 million years ago, the Odonate wings have flagged the triumph of insects over land and air. They set the invertebrate state of art for flying. The mastery of flying does not roam around, with aerial expertise, Odonates vie for the best hunter award.
Dragons in the air, dragons under water
Odonates have dual modes of life. They lay eggs in water and live there until adulthood. For other creepy-crawlies, this is a bad news. For scientists, it is a remarkably complex and equally interesting life cycle.
The life exhibits three stages: egg, nymph and adult. The first two is always aquatic, gill-breather, a much-prolonged form than its adulthood stage. The free flying terrestrial lung-breathers are what we see around and it constitutes only one brief stage of its life.
Having said so, all three equally predates on any prey fit under their mandible.
Assassin-class adaptations
Odonate nymphs go for several molts before merging into a flier. Unlike the scooper and chaser adults, soft-bodied juvies are ambush killers and for this, they have the ability of walking along the waterbed. Surprisingly, as grown-ups, Odonates give up walking. They can sit, but not walk; their legs being angled in 45° to catch prey in mid-air. Compound eyes become large and domical to ensure a broad range 360° view.
All four of Odonate's wings are extraordinarily uncoupled. The wings have no connection with each other and could beat up independently.
Dragonflies have the ability of hovering and turning 180° while in flight and flying backwards. The helicopter we see today is a giant mechanical dragonfly on its own.
Who is who
Based on body structure, Odonata are divided into two major suborders, viz: Zygoptera (damselflies) and Anisoptera (dragonflies). To keep the chronicle simple, damselflies are simply the delicate, comparatively weak miniature dragons having narrow, equally proportionate weak wings than other counterparts - the Anisopterans are with a robust, much larger dimension. Both subgroups have many families, some of which can stand as the most graceful insects.
The enigmatic yet least known
Of about 5,900 worldwide known Odonate species, merely 600 have been well documented from the Indian Subcontinent. In Bangladesh, Odontology, the study of dragonflies and damselflies, is still sprouting. Being a country from subtropics, the marshes, swamps, ditches, ponds, lakes and estuaries of Bangladesh offers an ideal residence for Odonata and a rich place to study Odontology.
A strong string in the web
In addition to aestheticism, dragonflies and damselflies are indispensable parts of the food web. Under water, Odonate nymphs are the chief predators of dipteran maggots i.e., the juvenile gnats, midges, mosquitoes and flies. Whereas the adult flies are always treated as delicacy to the grown-ups. Therefore, the next time you see dragonflies, they are doing pest-controls for free!
Subordinately, the nymph and adult warrior flies are naturally preyed upon by numerous shorebirds, herons, storks, bee-eaters, kingfishers etc. respectively. Without them, the larger animals would be in dire states.
Dragonflies are valuable bio-indicators and efficient pest repellers. Their life is interlaced with water. Many of them are strictly habitat-specific, presence or absence can actually say what is going on in the web of life.
The Odonates are now winning the science spotlights. Dragonfly enthusiasts in Bangladesh are increasing day by day. You can also join in!
