Folded pieces of paper become airplanes ready to be launched, eager gazes follow soaring eagles, and dragonflies are the helicopters of their fantasies. In the imagination of children, flying holds a special place .
Dragonflies (called sitara in Hindi) are indeed wonders of flight. These insects belong to a lineage whose members were among the planet’s first flying organisms. The spectacle of these giant ancestors of dragonflies would have left any modern observer spellbound. The pages of The Hindu sometimes feature colorful pictures of newly discovered Indian species, usually in either the Northeastern States or in the Western Ghats where Karnataka, Kerala, and Tamil Nadu meet. But alas, ecological surveys increasingly report missing dragonfly species and shrinking populations. In a world where public attention is fixated on large mammals, why do these ancient insects merit so much thought? Away from human-dominated landscapes as well, dragonfly populations are affected by a changing planet. Some species in the Western Ghats have evolved to flourish in forests where water seeps from wet marshy soil into mountain streams. In more recent years, cycles of drought and excessive rainfall have not been kind to several endemic Indian species, such as the blue hawklet ( Hylaeothemis apicalis, ), a strikingly colored dragonfly with blue-green eyes, but which is very rarely seen these days. we also continue to unearth new facets of what makes them unique While looking to dragonflies and damselflies as the bellwethers of our ecosystems. We humans make do with just four visual opsins: one each for the red, green, and blue colours in our cone cells and a fourth for low-light vision by the rod cells.
About 300 million years ago, their ancient kin had the same aerodynamic features, but with a wingspan that extended to 72 cm. India is home to around 600 species in the order Odonata , which includes dragonflies and the slender damselflies. Recent research on the eyes that provide 360-degree vision to dragonflies has shown that there are 16 or more genes that code for visual opsins, the proteins that detect colour and light. The molecular abundance gives dragonflies a very sensitive visual system that even perceives ultraviolet light ( PNAS 112 (11) E1247-E1256).
