The life cycle of a dragonfly.

Discover how the dragonfly develops underwater and emerges as a magnificent flying predator.

As the dragonfly mating season gets into full swing during the summer months, streaks of colour can be seen dashing across the sky. This is just the start of their long life cycle and it all begins midair, as the male dragonfly pursues a mate. Females can lay hundreds of eggs throughout their lives, depositing them in or on the surface of a nearby lake, stream or pond. It will take up to a week for the nymphs to emerge from the eggs and then it can be months or even years before some species reach the metamorphosis stage. In the meantime, the nymphs will continue to develop underwater, breathing through gills in their body and feeding off other insects and even live tadpoles and small fi sh. Unlike butterflies, dragonflies do not have a pupal stage. Instead, they emerge from the water where their exoskeleton cracks open and releases the insect’s four wings. The process takes about three hours to complete and then the young dragonfly must wait hours, or even days, for their wings to dry and harden. Their first flight usually only covers a few metres but soon they’ll be hurtling forward at speeds of 56 kilometres (35 miles) per hour, hovering for up to one minute and even flying backward or upside down. Incidentally, dragonflies were among the fi rst insects in the history of Earth to gain the ability to fly, existing about 300 million years ago with wingspans of 68 centimetres (26.8 inches). Today there are about 3,000 species in the world and their incredibly complex and well-choreographed reproduction method will secure this insect’s presence for years to come.

Developing colour 

Young adult dragonflies have very muted colours and faint markings when they fi rst emerge from their exoskeleton. It can take days for them to gain their full vibrant colour, as their bodies still need to harden in the Sun. Temperatures can also affect how strong colours and patterns appear, and the adult males are generally brighter and bolder in colour than the females. of course, strong vivid colours make it difficult for the dragonfly to remain inconspicuous, but its unique colour and pattern markings aren’t meant for camouflage. In fact, it helps the dragonfly survive as it warns potential predators that the insect may be poisonous. However, as the dragonfl y ages, colours can fade or even change completely. The common darter dragonfly, for example, will go from yellow to red.



For more tech news, pick up your copy of Issue 101 from all good retailers or from our website now. If you have a tablet or smartphone, you can also download the digital version onto your iOS or Android device. To make sure you never miss an issue of How It Works magazine, subscribe today!