Seeing dragonflies swoop over water is a quintessential sign that summer is upon us. When in flight their movements are mesmerising – using their two sets of wings either in synchrony or beating separately, they are able to fly in any direction they choose, altering their speed and movement instantly in mid-flight to create a dance that is unlike any other organism. But while the flying adults are frequently seen during the warmer months, many of us know very little about their life during the rest of the year.
In this article we will take a look at the dragonfly life cycle, explore how climate change and other threats are affecting dragonfly populations globally, and offer some tips on how to attract dragonflies to your garden.
Dragonfly life history
Dragonflies belong to the order Odonata within the sub-order Anisoptera (meaning ‘unequal-winged’). This order is also home to the closely-related damselflies (sub-order Zygoptera). Although at first glance dragonflies and damselflies appear similar, dragonflies are usually larger and bulkier with significantly larger eyes when compared to the slightly built and rather delicate damsels. When at rest dragonflies hold their wings open whereas damsels keep theirs closed, next to the body.
There are three distinct phases in the dragonfly life cycle: egg, nymph (larva) and adult.
Dragonflies breed in or on water bodies such as marshes, swamps, ponds, pools and rivers; after mating the female will lay hundreds of eggs over the course of several days or months. Some species lay their eggs inside plant material, either on the surface of the water or submerged. Others encase their eggs in a jelly-like substance and deposit them directly into the water. Eggs usually hatch within a few weeks, although some remain in the water throughout the colder months and hatch the following spring.
The first larva that hatches from the egg is known as a prolarva, and this very quickly moults into the first proper larval stage. The larvae, or nymphs, then proceed to moult a further 5–14 times – typically taking place over 1–2 years, although it can be as long as five years in species such as the Golden-Ringed Dragonfly. Nymphs continue to live in the water and are voracious eaters, feeding on insect larvae, crustaceans, worms, snails, tadpoles and even small fish.
Unlike many other flying insects, such as butterflies and moths, the final moult of the dragonfly does not feature a pupal stage – known as incomplete metamorphosis. This moult takes place out of the water where the winged adult emerges from the nymph skin, leaving behind an exuvia, or skin cast. A period of time is then spent feeding away from the water before the adult dragonfly returns to breed and begin the cycle again. Life expectancy of the adult dragonfly is short – typically only 1–2 weeks, although some will live for up to 5–6 weeks.
Conservation and climate change
An IUCN update in December 2021 stated that the destruction of wetlands is driving a worldwide decline in dragonflies. Despite their high ecological value, marshes, swamps and boggy areas continue to be degraded by intensified agriculture and urbanisation and, along with longer periods of drought, this is vastly reducing the amount of habitat in which dragonflies and damselflies can survive.
Clean water is also paramount for dragonfly nymphs – so much so that their presence is regarded as an useful indicator of wetland health. Pollution of waterways and water bodies by pesticides and effluent are problematic and are compounding the issue of habitat loss.
In their favour is the fact that dragonflies are highly mobile and appear to colonise new habitats relatively rapidly. With global temperatures on the rise, we are already seeing species shift to higher latitudes and altitudes. Even in the UK, Mediterranean migrants are being recorded with increasing frequency.
Which dragonflies are you most likely to see?
There are just under 30 species of dragonfly living in the UK. Identification of these is primarily achieved using the patterns and colouration of the thorax and abdomen, although a few similar species require the finer details, such as leg colour, to be examined.
Take a look at our article The NHBS Guide to UK Dragonfly Identification for ten of the most common and widespread species you are likely to spot in the UK.
Or why not check out this interactive map from the British Dragonfly Society where you can search for good places to look for dragonflies near you. You can also filter the results by species if you’re looking for something specific.
How to attract dragonflies to your garden
Water is an integral part of the dragonfly life cycle, so having a pond in your garden is by far the best way to attract them. If you only have a small outdoor space then sinking a bucket or trough into the ground is a low-cost and space-efficient solution. A larger pond with both floating and emergent vegetation, however, will provide dragonflies with somewhere to lay their eggs and for the nymphs to live once they have hatched. It is important to have some vegetation which extends out of the pond as this will allow nymphs to leave the water when they are ready to undergo the final moult into their adult, winged form. Ponds with carnivorous fish or those used by waterfowl will be less useful as these will both prey on the dragonfly larvae.
Having a variety of flowers and herbs growing nearby will help to attract other insects which the dragonflies will feed on. Providing some canes or small stakes will also give them a place to perch – this is particularly important in the morning when dragonflies need to spend time basking in the sun before their wing muscles are warm enough for flight.
• Dragonflies see the world in colour and can detect ultraviolet as well as blue, green and red.
• Dragonflies have been around for 300 million years. Their ancestors were some of the largest insects ever to have existed – some had wingspans of up to 80cm!
• Dragonflies are true acrobats and can fly both upside down and backwards.
• Although they can live for up to five or six years, dragonflies only spend a tiny portion of this time – between a week and two months – as the colourful flying adults that we recognise. The majority of their lives are spent in the water as nymphs (larvae).
Further reading and equipment
A superb identification guide with identification texts and distribution maps as well as an introduction to larvae identification. Each species is lavishly illustrated with artworks of males, females and variations, as well as close-ups of important identifying characters.
Written by two of Britain’s foremost dragonfly experts, this excellent guide is focused on the identification of both adults and larvae. It features hundreds of stunning images and identification charts covering all 57 resident, migrant and former breeding species, and six potential vagrants.
This handy and affordable fold-out guide from the Field Studies Council features 28 dragonfly and 16 damselfly species and is a useful aid to identifying them in the field, often while in flight. It is a perfect size to pack into a bag while out and about and is a great choice for beginners.