Coming of Age Underwater: The Life Cycle of Dragonflies and Damselflies

Photo Story Published : Mar 20, 2024 Updated : Mar 22, 2024

These breathtaking beauties spend much of their lives underwater. When they become adults, they take wing, with their agile bodies and lightning-fast reflexes set to dominate the insect world

Beyond the flutter of butterfly wings, another insect group, the odonates, has woven itself into the tapestry of human fascination. Most cultures have stories, songs, or other art forms centred around dragonflies and damselflies. However, under the shimmering wings and aerial dances, a whole chapter of the odonate story remains unread — their hidden underwater lives. Life begins in water for an odonate, as it hatches from an egg deposited by its parent in a pond, puddle, or stream. The tiny, aquatic larva bears no resemblance to the winged wonder it will become. It sheds its skin several times to grow in size, develops wing pads, and, when fully grown, climbs out of its watery world to execute its final moult and become the dazzling jewels we are familiar with.

While many recognise the breathtaking beauty of dragonflies and damselflies flitting through the air, their fierce predatory nature often goes unnoticed. These insects are masters of the miniature hunt, wielding their agile bodies and lightning-fast reflexes to dominate the insect world. Their carnivorous tendencies begin long before their wings unfurl. In their aquatic larval stage, these underwater assassins lie in wait, armed with a powerful extendable labium (lower jaw) that snatches unsuspecting prey, which may include small fish. They play a pivotal role in controlling insect populations and maintaining the delicate balance of freshwater habitats. But the true spectacle unfolds when they take to the skies. Adult odonates are aerial acrobats of death, equipped with exceptional manoeuvrability and razor-sharp vision. Odonates, however, do not sit comfortably on top of the food web. Underwater, fish, beetles, and diving birds make quick work of them. On the wing, drongos and bee-eaters pursue them while spiders and frogs orchestrate silent ambushes. Every flutter of an odonate’s wing is a testament to their resilience, each dazzling dance a celebration of survival against all odds.

For forming the “mating wheel” of odonates, the male grabs the female using appendages at the tip of its abdomen (anal appendages), and the female curls its abdomen to receive sperm from the male’s mating organ. In damselflies like this (1) saffron-faced blue dart (Pseudagrion rubriceps), the male’s anal appendages lock on to the female’s prothorax, while in dragonflies like the (2) crimson-tailed marsh hawk (Orthetrum pruinosum), they lock on to the back of the female’s head. In most odonate species, the male is more colourful and showier and defends a small part of a freshwater habitat as its territory. The drab-looking female makes the occasional visit to assess the suitability of the territory as an egg-laying habitat and, if satisfied, mates with the male.

In all odonates, mating is immediately followed by egg-laying. This is easier for most dragonflies, which lay their eggs directly on the water’s surface or stick them to floating algae or debris. Damselflies, however, pierce holes in aquatic plants or rotting wood floating in water to lay eggs. Female damselflies are equipped with ovipositors (tubular organs used to deposit eggs) at the tip of their abdomen to serve this purpose. While the female focuses on laying eggs, its partner keeps guard against potential intruders. In some species like this (1) saffron-faced blue dart, the male keeps holding the female in tandem using its anal appendages. In others, like the (2) river heliodor (*Libellago lineata*), the male keeps flying over the egg-laying female or perches close to it. This guarding is against other prospective males, which might hijack the female and replace the deposited sperms with their own. Odonates, especially the females, expose themselves to great dangers while laying eggs. Some even immerse their bodies completely in water to find the perfect spot to lay eggs. This is when a frog or a fish can easily gobble them up.

The eggs laid by odonates in tropical conditions hatch within a few weeks, and worm-like prolarvae (larval forms first hatched from the eggs) move to suitable habitats where they moult very soon to become larvae. (1) Larvae are ambush predators that lie camouflaged in mud or crouched among water plants. When a prey comes within striking distance of a larva, it shoots out its labium or “face mask” like a harpoon, impaling the quarry and pulling it into its mouth. Studies in Thailand and Malaysia have shown that dragonfly larvae are very effective at controlling mosquito wrigglers. Like their adult forms, damselfly larvae are slender and have leaf-like appendages at the end of their abdomen — a feature that the more robust dragonfly larvae lack. (2) When an odonate larva is fully grown after shedding its skin 8-10 times, it climbs out of the water and attaches itself to a secure place. Its wing pads are clearly visible in this stage. The larva is now ready for its final transformation.

The final moulting of an odonate usually happens under the cover of night. The exoskeleton of the larva splits along a weak suture behind the head. This is the moment of emergence, where the delicate adult begins to crawl out. (1) Initially, the young adult (called a teneral) appears pale and soft-bodied, with crumpled wings tightly pressed against its abdomen. Over the next few crucial hours, it undergoes several critical processes. (2) The teneral pumps haemolymph (insect “blood”) into its wing veins, causing them to expand and unfurl to their full size and shape. The abdomen stretches and lengthens, reaching its mature size. The soft, pale exoskeleton gradually hardens and darkens, taking on the vibrant colours of the adult.

Once their wings are dry and muscles warmed up, adult odonates take to the skies. Their four wings, independently controlled by powerful muscles, grant them unmatched agility and manoeuvrability. They can hover, dart, turn on a dime, and even fly backwards, leaving predators and prey dumbfounded. Their presence or absence in an area can indicate the health of a water body, as they exhibit varying sensitivity to pollution and changes in water quality. When seen in large numbers, the ditch jewel (*Brachithemis contaminata*) indicates a polluted waterbody.

Adult odonates are aerial hunting marvels. Their compound eyes spot prey accurately, while their agile wings allow them to swoop and snatch with lightning speed. Long legs with spines ensnare victims, and powerful mandibles tear them apart. (1) Damselflies like the coromandel marsh dart (*Ceriagrion coromandelianum*) pick off smaller insects from plants, while (2) dragonflies like the ditch jewel chase down their prey in flight. Odonates play a crucial role in our agroecosystems as natural pest controllers. They feast on a wide variety of crop pests, including aphids, leafhoppers, and beetles.

Dragonflies and damselflies serve as a critical link in the food web, supporting the overall biodiversity of ecosystems. The abundance of odonates provides an essential protein-rich diet for birds, contributing to their overall health and reproductive success. (1) As larvae, they become integral components of the food web, being preyed upon by various organisms, including waders like this little ringed plover. (2) Bee-eaters, drongos, and swallows are known to be avid consumers of odonates. Bee-eaters are particularly skilled at catching flying insects, including odonates.