Hitchhiking the Evolutionary Journey of Dragonflies - A personal reflection

Joel Sherjin

As a child, I was captivated by the image of a giant prehistoric dragonfly featured on the Discovery Channel amidst vivid portrayals of dinosaurs. The notion of a “helicopter insect” soaring through ancient skies sparked my imagination, picturing it skillfully hunting small avian dinosaurs, such as Achirons. The narrow but long path leading to my childhood home served as the perfect runway for my imaginative simulations of giant dragonflies landing and taking off, their immense wings stirring up dust as they whirred past. This is possibly my introduction to the world of dragonflies, and I would have had to time travel to 200 Million years ago to see perhaps these giant dragonflies close to home.

I grew up in a small village close to the southern tip of India, nestled between the Arabian Sea and the Western Ghats which certainly made for a rich ecological backdrop. It was much later, that I came to appreciate the significance of this geographical setting as I continued to encounter multiple wildlife, from porcupines and leopard cats to star tortoises. My study hours or rather the pretense of them were usually among sprawling mango trees offering a panoramic view of the wildlands interspersed with homes that offered ample opportunities to observe multiple avifauna, insects, and occasional snakes

One particularly memorable day as a 10-year-old, while drawing water from a nearby well, a tiny white twig emerged from the bushes, moving in an intriguing, helicopter-like manner. Upon closer examination, I discovered it was a damselfly, likely a member of the Copera genus. This encounter further ignited my ongoing quest to identify various colors of these damselflies around the house, which I did not expect in the future would take me from the pristine waters of the Himalayan floodplains to the sewage-adjacent drains of Chennai’s marshlands in search of them. Although I did not pursue a career in paleontology or wildlife biology, my involvement with the Society of Odonate Studies and the support of naturalist friends have enriched my understanding of these fascinating insects.

Odonates, comprising dragonflies and damselflies, have long fascinated me due to their unique adaptations and ecological roles. Most of my early explorations into Odonate biology were on the internet, rather than the Western Ghats or marshes, mostly towards their prehistoric relatives and their ancient habitats alongside dinosaurs. The evolutionary narrative of Odonates and their long-standing presence on Earth is an interesting pursuit, and helps understand why these rather small creatures are still dominant predators with the highest accuracy rates of hunting, acting as a top predator in several micro pools and undertaking some fascinating and longest of insect migrations across the globe.

A Historical Context: The Evolution of Dragonflies

India has one of the most dynamic tectonic histories of all the land masses. It was at the center of evolutionary history and continental shifts for millions of years. About 350 million years ago, the landmass was clustered into a C-shaped, almost Packman-looking Pangea. Roughly 250 million years ago, the supercontinent Pangaea began to fragment, and by around 135 million years ago, it had split into two primary landmasses: Laurasia and Gondwana. This segmentation marked the beginning of the Mesozoic Era, which culminated in a catastrophic mass extinction event around 65 million years ago, which possibly resulted in the departure of the dinosaurs. By this time, the continents roughly looked like the present-day arrangement. The most recent event was when the Indian Sub-continent drifted away from Africa and collided with the Asian subcontinent 10 million years ago, creating one of the youngest yet mighty mountains in the world, The Himalayas. To have a reference timescale, the early humans walked out of Africa to Asia around 1.8 Million years ago

In this vast timescale, Odonata emerged as one of the oldest insect lineages. These insects have undergone significant evolutionary changes, yet their fundamental morphology has remained remarkably stable since the time of the dinosaurs. Odonates are direct descendants of early winged insects called Griffin flies (Meganisoptera), evolving approximately 317 million years ago. The divergence to further Meganisozygoptera (Large dragonflies and damselflies) occurred about 250 million years ago, with distinct families separating approximately 50 million years later. A remnant of this predecessor of this Anisozygoptera (Epiophlebia laidlawi) dragonfly is still surviving in the Himalayas it is not segregated into either bucket of dragonflies and damselflies and is rightly called the Himalayan Relict Dragonfly. This dragonfly also happens to go through the longest dragonfly lifecycle, taking up to 9 years to emerge. Families of the present day, such as Aeshnidae and Gomphidae arose toward the end of the Jurassic period, around 65 million years ago.

The Odonata’s evolutionary path prompts curiosity: what did their prehistoric ancestors look like?

Recent developments in Phylogeny have made it feasible for detailed genomic studies showing the evolution of genetic architecture over an evolutionary timescale. Since Odonates are one of the first winged insects to occur, these genetic studies have revealed a much clearer picture of insect evolution, including hunting tactics, vision, reproduction, and other adaptations that gradually kept getting added to the precursor species over millions of years. Based on fossil records of early Meganisoptera, the present-day Odonata are not very different from their ancestors 300 million years ago. The flight, aggressive hunting, nymph survival in an aquatic ecosystem, and even the secondary sexual reproductive organs are a lot similar. Odonata can be perhaps a fragment cross-section of the evolutionary timeframe of life on Planet Earth, with the eggs developing in water to a nymph and then crawling onto the land, where they go through a major metamorphosis with possibly the gills developing into wings to further evolve into sky bound dragonflies.

These large and aggressive Megoanisoptera kept to the open plains, scanty forests, and grasslands owing to their sheer size limitation to traverse thickets. This left a vacuum for predators in the thicker forests and dense undergrowth, which resulted in the further evolution of a smaller Odonata (Damselflies) that had to evolve to be the first arboreal predators in the thicker forests. As giant predatory insects, these pre-Odonata were formidable aerial predators, in the absence of birds or other larger insects to prey on them.

Image 1: Meganisoptera and Meganisozygoptera among Dinosaurs possibly 150 million years ago

Image 2: Prehistoric Dragonfly Fossil representation

(Images generated by A.I assistance)

Odonates Through Time: From Meganeura to Modern Species

My search for those gigantic helicopter-sized dragonflies ended abruptly as I figured the largest of Meganisoptera was around 70 cm in wingspan, and it is still the largest insect to have roamed the earth. The first giant dragonfly fossil, a Meganeura was discovered in 1880 from a French Coal mine and described by paleontologist Charles Brongniart. This fossil specimen was very well preserved and was named Meganeura owing to the large, dense nerves on the wings. It took another 100 years, until 1979, to see the next finely preserved specimen. The largest dragonfly fossil is Meganeuropsis permiana, described in Kansas, US, in 1937, with a wingspan of 70 cms, the size of a bird, and is possibly the biggest known insect to have ever lived, weighing up to 150 grams. These discoveries were very pivotal in piecing together the evolutionary history of insect fauna across millions of years. In the pre-Jurassic world, it would have been a common sight to see open grasslands filled with these giants and all the smaller fauna scrambling to find hideouts. They also possibly had slow wing flaps of about 3-6 Hz in comparison with 30 Hz of a modern-day dragonfly, much like the gentle flutter of the Malabar Tree Nymph. Fossil Specimens of Meganeura permiana, were later discovered in other parts of the world as well, like China, Russia, and France, suggesting its pan-global presence at the time of its existence. Let us remember that the timescale here is when the earth was almost a single landmass, Pangea, and most life forms did not exist in isolated landscapes. This would mean that the same species could have very well existed in the Indian Subcontinent as well. India is yet to record any major mega dragonfly fossils, as most fossils discovered in India were of much smaller size akin to present-day dragonflies.

The Continuing Legacy of Odonates

The evolutionary journey of Odonates, from the colossal Meganeura to the diverse species we see today, is a testament to their resilience and adaptability in the face of changing environments. Their remarkable ability to thrive in various ecosystems underscores their ecological significance, not only as predators but also as indicators of environmental health. Today, when we see swarms of Globe Skimmers migrate from the Indian subcontinent to Seychelles and Africa, they are representing their prehistoric lineages from a distant past, over 100 million years ago, visiting their home grounds, which was once a single continuous continental mass with Africa and India being a part of the Gondwana. Through ongoing research and conservation efforts through academics, citizen science, and facilitators like the Society of Odonate Studies, we can better understand these fascinating insects and also take a closer look at the evolutionary history of faunal life on Earth that has evolved over millions of years.

The fascination with these creatures, which once filled my childhood imagination with thoughts of giants soaring through prehistoric skies, continues to inspire a deeper appreciation for the natural world and trying to look back into their evolutionary past. Ultimately, our understanding of their history compels us to protect that delicate balance of life that has evolved over millions of years and prevailed through the ages.

I might not have found the helicopter-sized dragonfly, which possibly did not exist at all, but the smaller dragonflies and damselflies of my backyard, with their fierce hunting strategies and unreal life cycles, still fascinate me way beyond my childhood imagination.