Damselfly (suborder Zygoptera)

Scientific Classification

Damselflies are placed in the order Odonata, within the winged insects (Insecta, Pterygota). Odonata is conventionally divided into the suborder Zygoptera, the damselflies, and the suborder Anisoptera, the dragonflies; a small relict group centred on the genus Epiophlebia has historically been treated as a third suborder, Anisozygoptera, and its placement has been revised repeatedly as new analyses appear. One consequence is worth flagging, because FaunaHub's own dragonfly profile follows it: under the Epiprocta treatment, Epiophlebia and the dragonflies are combined in a suborder Epiprocta and Anisoptera is demoted to an infraorder within it, which is why the dragonfly page calls Anisoptera an infraorder while this one calls it a suborder. Higher-level odonate classification is an active area, so the arrangement given here should be read as the conventional framework rather than a settled final answer.

Within Zygoptera the two families most people meet are the Calopterygidae, the broad-winged damselflies or demoiselles, and the Coenagrionidae, the narrow-winged or pond damselflies, which is the largest family in the suborder and accounts for most sightings in many regions. Other widely recognised families include the Lestidae, the spreadwings, and the Platycnemididae. Family limits and the number of accepted families have changed with molecular work, and the count of described species continues to rise, so any total should be treated as provisional.

Identification

Five features, used together, identify a damselfly rather than any single one on its own:

• Wings at rest. The wings are typically held closed above the abdomen or angled back alongside it, not held flat and outstretched to the sides.
• Matched, stalked wings. The forewing and hindwing are nearly identical in shape, and both narrow to a slender stalk at the base where they join the thorax.
• Widely separated eyes. The compound eyes sit far apart at either end of a broad, hammer-shaped head, with a clear span of head between them.
• Slender abdomen. The abdomen is long, thin and often nearly uniform in width, giving the insect a needle-like outline.
• Flight quality. Flight generally looks light and fluttering, over short distances and low among vegetation.

The wing-posture cue is strong but not absolute: spreadwings in the family Lestidae characteristically perch with the wings held partly open, which is why it is worth checking the head shape and the stalked wing bases as well. The two photographs on this page deliberately show different families — the hero image is a broad-winged demoiselle in the Calopterygidae, and the gallery image is a narrow-winged coenagrionid, the more typical body shape.

Appearance

Adult damselflies are small to medium insects with a compact thorax, four membranous net-veined wings and a conspicuously slim abdomen. Body length in many temperate species falls roughly in the range of about two to five centimetres, with demoiselles towards the larger end of that span; a handful of tropical damselflies, including the helicopter damselflies of the Neotropics, are considerably larger and among the longest-winged of all odonates. Sizes given in field guides vary with how they are measured and with the population sampled, so treat any single figure as approximate.

Colour is produced in two ways that behave differently. Pigment colours — the blacks, reds, yellows and the dark or metallic bands on demoiselle wings — are relatively stable, while structural and pruinose colours, such as the powdery blue bloom that develops on the abdomen of some mature males, can change as an individual ages and with temperature. Freshly emerged adults are teneral: pale, soft and dull, and they may look nothing like the mature insect. Sexes often differ in colour, and in several coenagrionid genera females occur in more than one colour form, including forms that resemble the male, which is a common source of misidentification.

Distribution

Damselflies occur on every continent except Antarctica, wherever suitable fresh water persists long enough for the nymphs to develop. Species richness is highest in the wet tropics, particularly in tropical forest streams and in the small water bodies of the forest canopy and understorey, and falls away towards high latitudes and high altitudes, where the flight season is short and the number of species that can complete development is limited. Oceanic islands typically hold far fewer species than nearby mainlands, and some island faunas contain endemic species found nowhere else.

Within a region, distribution is patchy in a way that follows water rather than land: a species may be locally common along one stream type and absent from an apparently similar catchment nearby. Ranges are not fixed, and recorders in several parts of the world have documented odonate species appearing further from the equator or higher in altitude than in earlier decades. Country and regional checklists are revised frequently, so the current distribution of a named species is best taken from an up-to-date national recording scheme or Red List assessment.

Adaptations

The most distinctive damselfly adaptation belongs to the nymph. At the tip of the abdomen it carries three external caudal lamellae — flattened, leaf-like or paddle-shaped gills that greatly increase the surface available for gas exchange in water. Dragonfly nymphs have no such structures, holding their gills internally at the rear of the digestive tract instead, so the three trailing paddles are the most useful field character for telling damselfly nymphs apart. They are not infallible, for two reasons the same paragraph should admit: in several species the lamellae can be shed if seized by a predator and regrown at later moults, so an individual may be missing them, and in some genera they are saccoid rather than leaf-like, while a few families — the Euphaeidae and Polythoridae among them — carry additional lateral abdominal gills as well. The lamellae also double as a small tail fin during the side-to-side swimming stroke.

Adults show a different set of solutions. The stalked wing bases and independently worked wings allow slow, precise flight through dense vegetation, where speed matters less than control, and the spiny legs form a forward-facing basket that scoops prey from foliage. Reproduction involves an unusual arrangement shared with dragonflies: the male transfers sperm from the tip of his abdomen to secondary genitalia near its base before mating, and in many damselflies the male's genitalia can also displace sperm already stored by the female, one of the classic examples of sperm competition in insects. Females of most species have a well-developed, blade-like ovipositor for inserting eggs into plant tissue.

Life Cycle & Reproduction

Damselflies develop by incomplete metamorphosis: egg, aquatic nymph, and winged adult, with no pupal stage. Mating begins with the tandem position, the male gripping the female behind the head with abdominal claspers, and proceeds to the wheel position, in which the pair form the familiar heart or circle shape while the female brings the tip of her abdomen to the male's secondary genitalia. Pairs may remain in tandem afterwards, and males of many species guard the female while she lays, either still attached or hovering nearby.

Most female damselflies lay endophytically, cutting into stems, floating leaves or submerged vegetation with the ovipositor and placing eggs inside the plant tissue rather than scattering them into open water; in some species the female crawls or is led beneath the surface to do so. The nymph that hatches passes through a series of moults, growing wing pads as it goes, and may spend anywhere from a few months to a year or more in the water depending on species, temperature and food. Emergence is the final transition: the full-grown nymph climbs a stem clear of the water, the skin splits, and the teneral adult withdraws, expands its wings and hardens over the following hours to days.

Lifespan

In the wild. The great majority of a damselfly's life is the underwater nymph stage, which commonly lasts from a few months to a year or more, and longer still in cold water or at high latitude where growth is slow. The winged adult stage is far shorter: a few weeks is typical for many species once the insect has matured, though a small number of damselflies, including some spreadwings, overwinter as adults and so live considerably longer in total. Mortality is heavy at every stage, and the average individual lives nowhere near the maximum recorded for its species.

Under human care. Damselflies are not kept as companion animals, and the only sustained experience of holding them comes from research and educational rearing, where nymphs are raised in tanks to study development or emergence. Figures from such settings describe controlled conditions with a stable food supply and no predators, and they are not interchangeable with wild lifespans; the two should always be reported separately. Published values in both categories vary widely between species and studies, so they are best read as ranges rather than as a single expected age.

Conservation Context

No single conservation status applies to damselflies as a whole. Zygoptera contains many widespread and locally abundant species alongside narrowly restricted ones known from a single stream system or island, and assessed categories across the suborder span the full range. A status is also a snapshot rather than a permanent property: assessments are periodically revised as new survey data, taxonomic changes and habitat trends come in, so any category quoted here or elsewhere may already be out of date. The current assessment for a named species should be read directly from the IUCN Red List.

Where damselflies are of conservation concern, the pressures are usually the freshwater pressures: drainage and infilling of small wetlands, canalisation and dredging, loss of marginal and submerged plants, siltation, nutrient enrichment and pollution, shading of formerly open streams, and changes to flow regimes. Species tied to a single habitat type — a particular stream character, a seepage, or forest phytotelmata — are inherently more exposed than generalists of ordinary ponds. Because the nymphs integrate conditions over months, odonate recording is often used as one strand of freshwater habitat assessment rather than as a measure of the insects alone.

What the Name Covers

“Damselfly” is a group name, not a species. It refers to the whole suborder Zygoptera and carries no more precision than a word like “beetle” or “finch”: any statement about size, colour, flight season or status only becomes checkable once a family, genus or species is named. The spelling “damsel fly” as two words is sometimes seen but the single word is standard in modern usage.

Regional naming adds further layers. In Britain and much of Europe the broad-winged Calopterygidae are called demoiselles, while in North America many of the small blue-and-black coenagrionids are known as bluets; both names sit inside Zygoptera rather than outside it. Local folklore names such as “devil's darning needle” have been applied loosely to odonates in general, damselflies and dragonflies alike, and carry no taxonomic meaning.

Three confusions recur. Damselflies are routinely mistaken for the dragonflies covered separately on FaunaHub, which are the other suborder of the same order. They are also confused with mayflies, which are a different order altogether — mayflies hold the wings upright over the back, usually show two or three long tail filaments, and have non-functional mouthparts as adults. Finally, some lacewings and antlions are mistaken for damselflies because they too have net-veined wings, but they belong to a separate order and typically hold the wings in a tent shape over the body.