Damselflies are
flying insect
The Pterygota ( grc, πτερυγωτός, pterugōtós, winged) are a subclass of insects that includes the winged insects. It also includes insect orders that are secondarily wingless (that is, insect groups whose ancestors once had wings b ...
s of the suborder Zygoptera in the order
Odonata
Odonata is an order of flying insects that includes the dragonflies and damselflies. Members of the group first appeared during the Triassic, though members of their total group, Odonatoptera, first appeared in Late Carboniferous.
The two comm ...
. They are similar to
dragonflies
A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threa ...
, which constitute the other odonatan suborder, Anisoptera, but are smaller and have slimmer bodies. Most species fold the wings along the body when at rest, unlike dragonflies which hold the wings flat and away from the body. An ancient group, damselflies have existed since at least the
Lower Permian
The Cisuralian is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan and ...
, and are found on every continent except
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
.
All damselflies are
predatory insect
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill t ...
s; both
nymph
A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ty ...
s and adults actively hunt and eat other insects. The nymphs are aquatic, with different species living in a variety of
freshwater habitat
Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes, ponds, rivers, streams, springs, bogs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be ...
s including acidic
bogs,
pond
A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from th ...
s,
lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
s and
river
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...
s. The nymphs
moult
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
repeatedly, at the last moult climbing out of the water to undergo
metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...
. The skin splits down the back, they emerge and inflate their wings and abdomen to gain their adult form. Their presence on a body of water indicates that it is relatively unpolluted, but their dependence on freshwater makes them vulnerable to damage to their
wetland
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...
habitats.
Some species of damselfly have elaborate
courtship
Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...
behaviours. Many species are
sexually dimorphic
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
, the males often being more brightly coloured than the females. Like dragonflies, they reproduce using indirect
insemination
Insemination is the introduction of sperm into a female’s reproductive system for the purpose of impregnating, also called fertilizing, the female for sexual reproduction. The sperm is introduced into the uterus of a mammal or the oviduct of an ...
and delayed
fertilisation
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...
. A mating pair form a shape known as a "heart" or "wheel", the male clasping the female at the back of the head, the female curling her abdomen down to pick up sperm from secondary genitalia at the base of the male's abdomen. The pair often remain together with the male still clasping the female while she lays eggs within the tissue of plants in or near water using a robust
ovipositor
The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
.
Artificial fishing flies that mimic damselfly nymphs are used in wet-
fly fishing
Fly fishing is an angling method that uses a light-weight lure—called an artificial fly—to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. The light weight requires casting techniques significantly diffe ...
. Damselflies are sometimes represented in personal jewellery such as brooches.
Classification
The Zygoptera are an ancient group, with
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s known from the lower
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
, at least 250 million years ago. All the fossils of that age are of adults, similar in structure to modern damselflies, so it is not known whether their larvae were aquatic at that time. The earliest larval odonate fossils are from the
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...
.
Fossils of damselfly-like Protozygoptera date back further to 311–30 Mya. Well-preserved
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
damselfly larvae and exuviae are known from fossils preserved in
amber
Amber is fossilized tree resin that has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects."Amber" (2004). In Ma ...
in the Baltic region.
Molecular analysis in 2013 confirms that most of the traditional families are
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
, but shows that the
Amphipterygidae
''Amphipteryx'' is a genus of damselflies, the only genus in the family Amphipterygidae.Jocque, M. & Argueta, I. (2014)A new species in the genus ''Amphipteryx'' Selys, 1853 (Odonata, Amphipterygidae) from Pico Bonito National Park, Honduras.''Z ...
,
Megapodagrionidae
The Megapodagrionidae are a family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-bei ...
and
Protoneuridae
The Protoneuridae are a family of damselflies. Most species are commonly known as threadtails, while others are commonly known as bambootails.
Characteristics
These are usually small-sized damselflies and their wings are narrow and mostly tran ...
are
paraphyletic
In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
and will need to be reorganised. The Protoneuridae in particular is shown to be composed of six clades from five families. The result so far is 27 damselfly families, with 7 more likely to be created. The discovered
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
s did not agree well with traditional characteristics used to classify living and fossil Zygoptera such as wing venation, so fossil taxa will need to be revisited. The 18 extant traditional families are provisionally rearranged as follows (the 3 paraphyletic families disappearing, and many details not resolved):
Dashed lines indicate unresolved relationships.
General description
![Pseudagrion microcephalum wing 0117](https://upload.wikimedia.org/wikipedia/commons/4/45/Pseudagrion_microcephalum_wing_0117.svg)
The general body plan of a damselfly is similar to that of a dragonfly. The
compound eyes
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distin ...
are large but are more widely separated and relatively smaller than those of a dragonfly. Above the eyes is the frons or forehead, below this the clypeus, and on the upper lip the
labrum, an extensible organ used in the capture of
prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
. The top of the head bears three simple eyes (
ocelli
A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-l ...
), which may measure light intensity, and a tiny pair of
antennae that serve no olfactory function but may measure air speed.
Many species are
sexually dimorphic
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
; the males are often brightly coloured and distinctive, while the females are plainer,
cryptically coloured, and harder to identify to species. For example, in ''
Coenagrion
''Coenagrion'' is a genus of damselflies in the family Coenagrionidae,
commonly called the Eurasian Bluets (although three species are found in North America: '' Coenagrion angulatum'', '' Coenagrion interrogatum'', and '' Coenagrion resolutum' ...
'', the Eurasian bluets, the males are bright blue with black markings, while the females are usually predominantly green or brown with black. A few dimorphic species show female-limited polymorphism, the females being in two forms, one form distinct and the other with the patterning as in males. The ones that look like males, andromorphs, are usually under a third of the female population but the proportion can rise significantly and a theory that explains this response suggests that it helps overcome harassment by males. Some Coenagrionid damselflies show male-limited polymorphism, an even less understood phenomenon.
In general, damselflies are smaller than dragonflies, the smallest being members of the genus ''
Agriocnemis'' (wisps). However, members of the
Pseudostigmatidae
The Pseudostigmatidae are a family of tropical damselflies, known as helicopter damselflies, giant damselflies, or forest giants. The family includes the largest of all damselfly species. They specialize in preying on web-building spiders, and ...
(helicopter damselflies or forest giants) are exceptionally large for the group, with wingspans as much as in ''
Megaloprepus'' and body length up to in ''
Pseudostigma aberrans
''Pseudostigma'' is a genus of damselflies in the family Pseudostigmatidae
The Pseudostigmatidae are a family of tropical damselflies, known as helicopter damselflies, giant damselflies, or forest giants. The family includes the largest of ...
''.
![Pseudagrion caffrum abdomen detail](https://upload.wikimedia.org/wikipedia/commons/0/0e/Pseudagrion_caffrum_abdomen_detail.jpg)
The first
thoracic
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...
segment is the prothorax, bearing the front pair of legs. The joint between head and prothorax is slender and flexible, which enables the damselfly to swivel its head and to manoeuvre more freely when flying. The remaining thoracic segments are the fused mesothorax and metathorax (together termed the
synthorax
The thorax is the midsection ( tagma) of the hexapod body (insects and entognathans). It holds the head, legs, wings and abdomen. It is also called mesosoma or cephalothorax in other arthropods.
It is formed by the prothorax, mesothorax and met ...
), each with a pair of wings and a pair of legs. A dark stripe known as the humeral stripe runs from the base of the front wings to the second pair of legs, and just in front of this is the pale-coloured, antehumeral stripe.
[
]
The forewings and hindwings are similar in appearance and are membranous, being strengthened and supported by longitudinal veins that are linked by many cross-veins and that are filled with haemolymph
Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which ...
. Species markers include quadrangular markings on the wings known as the pterostigma
The pterostigma (plural: pterostigmata) is a group of specialized cells in the outer insect wing, wings of insects, which are often thickened or coloured, and thus stand out from other cells. It is particularly noticeable in dragonfly, dragonfli ...
or stigma, and in almost all species, there is a nodus
This glossary of entomology describes terms used in the formal study of insect species by entomologists.
A–C
A synthetic chlorinated hydrocarbon insecticide, toxic to vertebrates. Though i ...
near the leading edge. The thorax houses the flight muscles.[ Many damselflies (e.g. Lestidae, Platycnemidae, Coenagrionidae) have clear wings, but some (Calopterygidae, Euphaeidae) have coloured wings, whether uniformly suffused with colour or boldly marked with a coloured patch. In species such as the banded demoiselle, '']Calopteryx splendens
The banded demoiselle (''Calopteryx splendens'') is a species of damselfly belonging to the family Calopterygidae. It is often found along slow-flowing streams and rivers. It is a Eurasian species occurring from the Atlantic coast eastwards to L ...
'' the males have both a darker green body and large dark violet-blue patches on all four wings, which flicker conspicuously in their aerial courtship dances; the females have pale translucent greenish wings.
The abdomen is long and slender and consists of ten segments. The secondary genitalia in males are on the undersides of segments two and three and are conspicuous, making it easy to tell the sex of the damselfly when viewed from the side. The female genital opening is on the underside between segments eight and nine. It may be covered by a subgenital plate, or extended into a complex ovipositor that helps them lay eggs within plant tissue. The tenth segment in both sexes bears cerci and in males, its underside bears a pair of paraprocts.[
Damselflies (except spreadwings, ]Lestidae
The Lestidae are a rather small family of cosmopolitan, large-sized, slender damselflies,
known commonly as the spreadwings or spread-winged damselflies.
Characteristics
While most damselflies rest with their wings folded together, most member ...
) rest their wings together, above their bodies, whereas dragonflies rest with their wings spread diametrically apart; the spreadwings rest with their wings slightly apart. Damselflies have slenderer bodies than dragonflies, and their eyes do not overlap. Damselfly nymphs differ from dragonflies nymphs in that they possess caudal gills (on the abdomen) whereas dragonflies breathe through the rectum. Damselfly nymphs swim by fish-like undulations, the gills functioning like a tail. Dragonfly nymphs can forcibly expel water in their rectum for rapid escape.
Distribution and diversity
Odonates are found on all the continents except Antarctica. Although some species of dragonfly have wide distributions, damselflies tend to have smaller ranges. Most odonates breed in fresh-water; a few damselflies in the family Caenagrionidae breed in brackish water (and a single dragonfly species breeds in seawater). Dragonflies are more affected by pollution than are damselflies. The presence of odonates indicates that an ecosystem is of good quality. The most species-rich environments have a range of suitable microhabitats, providing suitable water bodies for breeding.
Although most damselflies live out their lives within a short distance of where they were hatched, some species, and some individuals within species, disperse more widely. Forktails in the family Coenagrionidae
The insect family Coenagrionidae is placed in the order Odonata and the suborder Zygoptera.
The Zygoptera are the damselflies, which although less known than the dragonflies, are no less common. More than 1,300 species are in this family, making i ...
seem particularly prone to do this, large male boreal bluets (''Enallagma boreale'') in British Columbia often migrating, while smaller ones do not.[ These are known to leave their waterside habitats, flying upwards till lost from view, and presumably being dispersed to far off places by the stronger winds found at high altitudes.][ In this way they may appear in a locality where no damselflies were to be seen the day before. Rambur's forktail (''Ischnura ramburii'') has been found, for example, on oil rigs far out in the ]Gulf of Mexico
The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
.[
The distribution and diversity of damselfly species in the ]biogeographical
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, i ...
regions is summarized here. (There are no damselflies in the Antarctic
The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...
.) Note that some species are widespread and occur in multiple regions.
Overall, there are about 2942 extant species of damselflies placed in 309 genera.
Biology
Adult damselflies catch and eat flies, mosquitoes, and other small insects. Often they hover among grasses and low vegetation, picking prey off stems and leaves with their spiny legs.[ Although predominantly using vision to locate their prey, adults may also make use of olfactory cues. No species are known to hunt at night, but some are crepuscular, perhaps taking advantage of newly hatched flies and other aquatic insects at a time when larger dragonflies are roosting.][ In tropical South America, helicopter damselflies (]Pseudostigmatidae
The Pseudostigmatidae are a family of tropical damselflies, known as helicopter damselflies, giant damselflies, or forest giants. The family includes the largest of all damselfly species. They specialize in preying on web-building spiders, and ...
) feed on spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
s, hovering near an orb web and plucking the spider, or its entangled prey, from the web. There are few pools and lakes in these habitats, and these damselflies breed in temporary water bodies in holes in trees, the rosettes of bromeliad
The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...
s and even the hollow stems of bamboo
Bamboos are a diverse group of evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family. The origin of the word "bamboo" is uncertain, bu ...
s.
The nymphs of damselflies have been less researched than their dragonfly counterparts, and many have not even been identified. They choose their prey according to size and seem less able to overpower larger prey than can dragonfly nymphs. The major part of the diet of most species appears to be crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s such as water fleas
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms).
Over 1000 species have been recognised so far, with many more ...
.[
]
Ecology
Damselflies exist in a range of habitats in and around the wetlands needed for their larval development; these include open spaces for finding mates, suitable perches, open aspect, roosting sites, suitable plant species for ovipositing and suitable water quality, and odontates have been used for bio-indication purposes regarding the quality of the ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
. Different species have different requirements for their larvae with regard to water depth, water movement and pH.
The European common blue damselfly
''Enallagma cyathigerum'' (common blue damselfly, common bluet, or northern bluet) is a species found mainly between latitudes 40°N and 72°N; It is widely distributed in the Palearctic, and the Nearctic species '' Enallagma annexum'' was at on ...
(''Enallagma cyathigerum'') for example can occur at high densities in acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
waters where fish are absent, such as in bog pools.
The scarce blue-tailed damselfly
The scarce blue-tailed damselfly or small bluetail (''Ischnura pumilio'') is a member of the damselfly family Coenagrionidae.
The species occurs throughout Europe except in the north. To the east it occurs from Asia Minor to SiberiaTo the south ...
(''Ischnura pumilio'') in contrast requires base-rich
In ecology, base-richness is the level of Base (chemistry), chemical bases in water or soil, such as calcium or magnesium ions. Many organisms prefer base-rich environments. Chemical bases are alkalis, hence base-rich environments are either pH, ...
habitats and water with a slow flow-rate. It is found in ditches, quarries, seeps, flushes, marshes and pools. It tolerates high levels of zinc and copper in the sediment but requires suitable emergent plants for egg-laying without the water being choked by plants.[ Damselflies' dependence on freshwater habitats makes them very vulnerable to damage to wetlands through drainage for agriculture or urban growth.]
In the tropics, the helicopter damselfly ''Mecistogaster modesta'' (Pseudostigmatidae
The Pseudostigmatidae are a family of tropical damselflies, known as helicopter damselflies, giant damselflies, or forest giants. The family includes the largest of all damselfly species. They specialize in preying on web-building spiders, and ...
) breeds in phytotelmata
Phytotelma (plural phytotelmata) is a small water-filled cavity in a terrestrial plant. The water accumulated within these plants may serve as the habitat for associated fauna and flora.
A rich literature in German summarised by Thienemann (19 ...
, the small bodies of water trapped by bromeliad
The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...
s, epiphytic
An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...
plants of the rainforest
Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...
of northwest Costa Rica
Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
, at the high density of some 6000 larvae per hectare in patches of secondary forest. Another tropical species, the cascade damselfly ''Thaumatoneura inopinata
''Thaumatoneura inopinata'' is a species of damselfly, sometimes called the cascade damselfly or giant waterfall damsel, and the only member of the genus ''Thaumatoneura''. It is unusual in flying among the falling water and spray from waterfall ...
'' (Megapodagrionidae
The Megapodagrionidae are a family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-bei ...
), inhabits waterfall
A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf.
Waterfalls can be formed in several wa ...
s in Costa Rica and Panama.
Damselflies, both nymphs and adults, are eaten by a range of predators
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
including birds, fish, frogs, dragonflies, other damselflies, water spiders, water beetle
A water beetle is a generalized name for any beetle that is adapted to living in water at any point in its life cycle. Most water beetles can only live in fresh water, with a few Marine (ocean), marine species that live in the intertidal zone or l ...
s, backswimmers and giant water bugs
Belostomatidae is a family of freshwater hemipteran insects known as giant water bugs or colloquially as toe-biters, Indian toe-biters, electric-light bugs, alligator ticks, or alligator fleas (in Florida). They are the largest insects in the or ...
.
Damselflies have a variety of internal and external parasites. Particularly prevalent are the gregarine protozoans found in the gut. In a study of the European common blue damselfly, every adult insect was infected at the height of the flying season. When present in large numbers, these parasites can cause death by blocking the gut.[ Bright red water mites ]Hydracarina
Hydrachnidia, also known as "water mites", Hydrachnidiae, Hydracarina or Hydrachnellae, are among the most abundant and diverse groups of Benthic zone, benthic arthropods, composed of 6,000 described species from 57 families. As water mites of ...
are often seen on the outside of both nymphs and adults, and can move from one to the other at metamorphosis.[ They suck the body fluids and may actually kill young nymphs, but adults are relatively unaffected, it being necessary for the completion of the mite's life cycle that it returns to water, a feat accomplished when the adult damselfly breeds.
]
Behaviour
Many damselflies have elaborate courtship behaviours. These are designed to show off the male's distinctive characteristics, bright colouring or flying abilities, thus demonstrating his fitness. '' Calopteryx'' males will hover in front of a female with alternating fast and slow wingbeats; if she is receptive she will remain perched, otherwise she will fly off. The male river jewelwing (''Calopteryx aequabilis'') performs display flights in front of the female, fluttering his forewings while keeping his hindwings still, and raising his abdomen to reveal the white spots on his wings. ''Platycypha
''Platycypha'' is a genus of African damselflies in the jewel damselfly family (Chlorocyphidae).
The genus contains the following species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as ...
'' males will hover in front of a female, thrusting their bright white legs forward in front of their heads. Flattened tibia and bright leg colouring are seen in '' Platycnemis phasmovolans'' and a few other Platycnemididae
The Platycnemididae are a family of damselflies.
They are known commonly as white-legged damselflies. There are over 400 species native to the Old World.Dijkstra, K. D. B., Kalkman, V. J., Dow, R. A., Stokvis, F. R., & Van Tol, J. (2014)Redefini ...
including the extinct '' Yijenplatycnemis huangi''. ''Rhinocypha
''Rhinocypha'' is a genus of damselflies in the family Chlorocyphidae
Chlorocyphidae is a family of damselflies, commonly known as jewels. These are colorful species native to the Old World tropics, where they occur along forest streams. The ...
'' will bob up and down, often low over fast-flowing forested and shaded streams, displaying their bright-coloured bodies and wings. Male members of the family Protoneuridae
The Protoneuridae are a family of damselflies. Most species are commonly known as threadtails, while others are commonly known as bambootails.
Characteristics
These are usually small-sized damselflies and their wings are narrow and mostly tran ...
with vividly coloured wings display these to visiting females. Swift forktail (''Ischnura erratica'') males display to each other with their blue-tipped abdomens raised.
Other behaviours observed in damselflies include wing-warning, wing-clapping, flights of attrition and abdominal bobbing. Wing-warning is a rapid opening and closing of the wings and is aggressive, while wing-clapping involves a slower opening of the wings followed by a rapid closure, up to eight times in quick succession, and often follows flight; it may serve a thermo-regulatory function. Flights of attrition are engaged in by the ebony jewelwing
The ebony jewelwing (''Calopteryx maculata'') is a species of broad-winged damselfly. One of about 150 species of Calopterygidae, it is found in the eastern U.S. and southeastern Canada, ranging west to the Great Plains. Other common names includ ...
(''Calopteryx maculata'') and involve males bouncing around each other while flying laterally and continuing to do so, sometimes over a considerable distance, until one insect is presumably exhausted and gives up.
At night, damselflies usually roost in dense vegetation, perching with the abdomen alongside a stem. If disturbed they will move around to the other side of the stem but will not fly off. Spreadwings fully fold their wings when roosting.[ The desert shadowdamsel (''Palaemnema domina'') aggregates to roost in thick places near streams in the heat of the day. While there it engages in wing-clapping, the exact function of which is unknown. Some species such as the rubyspot damselfly, '' Hetairina americana'', form night roosting aggregations, with a preponderance of males; this may have an anti-predator function or may be simply the outcome of choosing safe roosting sites.]
Reproduction
Mating in damselflies, as in dragonflies, is a complex, precisely choreographed process involving both indirect insemination and delayed fertilisation. The male first has to attract a female to his territory, continually driving off rival males. When he is ready to mate, he transfers a packet of sperm from his primary genital opening on segment 9, near the end of his abdomen, to his secondary genitalia on segments 2–3, near the base of his abdomen. The male then grasps the female by the head with the claspers at the end of his abdomen; the structure of the claspers varies between species, and may help to prevent interspecific mating. The pair fly in tandem with the male in front, typically perching on a twig or plant stem. The female then curls her abdomen downwards and forwards under her body to pick up the sperm from the male's secondary genitalia, while the male uses his "tail" claspers to grip the female behind the head: this distinctive posture is called the "heart" or "wheel"; the pair may also be described as being "in cop". Males may transfer the sperm to their secondary genitalia either before a female is held, in the early stage when the female is held by the legs or after the female is held between the terminal claspers. This can lead to variations in the tandem postures. The spermatophore may also have nutrition in addition to sperms as a "nuptial gift
A nuptial gift is a nutritional gift given by one partner in some animals' sexual reproduction practices.
Formally, a nuptial gift is a material presentation to a recipient by a donor during or in relation to sexual intercourse that is not simpl ...
". Some cases of sexual cannibalism
Sexual cannibalism is when an animal, usually the female, cannibalizes its mate prior to, during, or after copulation.Polis, G.A. & Farley, R.D. Behavior and Ecology of Mating in the journal of Arachnology 33-46 (1979). It is a trait observed in m ...
exist where females (of '' Ischnura graellsii'') eat males while in copula.
Parthenogenesis
Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development ...
(reproduction from unfertilised eggs) is exceptional, and has only been recorded in nature in female '' Ischnura hastata'' on the Azores Islands
)
, motto =( en, "Rather die free than subjected in peace")
, anthem= ( en, "Anthem of the Azores")
, image_map=Locator_map_of_Azores_in_EU.svg
, map_alt=Location of the Azores within the European Union
, map_caption=Location of the Azores wi ...
.
Egg-laying (ovipositing) involves not only the female darting over floating or waterside vegetation to deposit eggs on a suitable substrate, but the male hovering above her, mate-guarding, or in some species continuing to clasp her and flying in tandem. The male attempts to prevent rivals from removing his sperm and inserting their own, a form of sperm competition
Sperm competition is the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and ...
(the sperms of the last mated male have the greatest chance of fertilizing the eggs, also known as sperm precedence) made possible by delayed fertilisation and driven by sexual selection
Sexual selection is a mode of natural selection in which members of one biological sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of t ...
.[ If successful, a rival male uses his penis to compress or scrape out the sperm inserted previously; this activity takes up much of the time that a copulating pair remain in the heart posture. Flying in tandem has the advantage that less effort is needed by the female for flight and more can be expended on egg-laying, and when the female submerges to deposit eggs, the male may help to pull her out of the water.][
Hetaerina americana-mating.webm, '' Hetaerina americana'' mating: sperm removal
]
All damselflies lay their eggs inside plant tissues; those that lay eggs underwater may submerge themselves for 30 minutes at a time, climbing along the stems of aquatic plants and laying eggs at intervals. For example, the red-eyed damselfly '' Erythromma najas'' lays eggs, in tandem, into leaves or stems of floating or sometimes emergent plants; in contrast, the scarce bluetail '' Ischnura pumilio'' oviposits alone, the female choosing mostly emergent grasses and rushes, and laying her eggs in their stems either above or just below the waterline. The willow emerald ''Chalcolestes viridis
''Chalcolestes viridis'', formerly ''Lestes viridis'', is a damselfly of the family Lestidae. It has a metallic green body and at rest it holds its wings away from its body. Its common name is the willow emerald damselfly, the green emerald damse ...
'' (a spreadwing) is unusual in laying eggs only in woody plant tissue, choosing thin twigs of trees that hang over water, and scarring the bark in the process. A possible exception is an apparent instance of ovo-viviparity, in which '' Heliocypha perforata'' was filmed in western China depositing young larvae (presumably hatched from eggs inside the female's body) onto a partly submerged branch of a tree.
Many damselflies are able to produce more than one brood per year (voltinism
Voltinism is a term used in biology to indicate the number of broods or generations of an organism in a year. The term is most often applied to insects, and is particularly in use in sericulture, where silkworm varieties vary in their voltinism.
...
); this is negatively correlated with latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
, becoming more common towards the equator, except in the Lestidae.
Life cycle
Damselflies are hemimetabolous
Hemimetabolism or hemimetaboly, also called incomplete metamorphosis and paurometabolism,McGavin, George C. ''Essential Entomology: An Order-by-Order Introduction''. Oxford: Oxford University Press, 2001. pp. 20. is the mode of development of certa ...
insects that have no pupal stage in their development. The female inserts the eggs by means of her ovipositor into slits made in water plants or other underwater substrates and the larvae, known as naiads or nymphs, are almost all completely aquatic.[ Exceptions include the Hawaiian '' Megalagrion oahuense'' and an unidentified Megapodagrionid from New Caledonia, which are terrestrial in their early stages.][ The spreadwings lay eggs above the waterline late in the year and the eggs overwinter, often covered by snow. In spring they hatch out in the meltwater pools and the nymphs complete their development before these temporary pools dry up.][
]
The nymphs are voracious predators
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
and feed by means of a flat labium (a toothed mouthpart on the lower jaw) that forms the so-called mask; it is rapidly extended to seize and pierce the ''Daphnia
''Daphnia'' is a genus of small planktonic crustaceans, in length. ''Daphnia'' are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembl ...
'' (water fleas), mosquito
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
larvae, and other small aquatic organisms on which damselfly nymphs feed. They breathe by means of three large external, fin-like gills on the tip of the abdomen, and these may also serve for locomotion in the same manner as a fish's tail.[ Compared to dragonfly larvae, the nymphs show little variation in form. They tend to be slender and elongate, many having morphological adaptations for holding their position in fast flowing water. They are more sensitive than dragonfly nymphs to oxygen levels and suspended fine particulate matter, and do not bury themselves in the mud.]
The nymphs proceed through about a dozen moults as they grow. In the later stages, the wing pads become visible. When fully developed, the nymphs climb out of the water and take up a firm stance, the skin on the thorax splits and the adult form wriggles out. This has a soft body at first and hangs or stands on its empty larval case. It pumps haemolymph into its small limp wings, which expand to their full extent. The haemolymph is then pumped back into the abdomen, which also expands fully. The exoskeleton
An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the ...
hardens and the colours become more vivid over the course of the next few days. Most damselflies emerge in daytime and in cool conditions the process takes several hours. On a hot day, the cuticle hardens rapidly and the adult can be flying away within half an hour.[
]
Conservation
Conservation of Odonata has usually concentrated on the more iconic suborder Anisoptera, the dragonflies. However, the two suborders largely have the same needs, and what is good for dragonflies is also good for damselflies. The main threats experienced by odonates are the clearance of forests, the pollution of waterways, the lowering of groundwater levels, the damming of rivers for hydroelectric schemes and the general degradation of wetlands and marshes. The clearance of tropical rainforests is of importance because the rate of erosion increases, streams and pools dry up and waterways become clogged with silt. The presence of alien species can also have unintended consequences
In the social sciences, unintended consequences (sometimes unanticipated consequences or unforeseen consequences) are outcomes of a purposeful action that are not intended or foreseen. The term was popularised in the twentieth century by Ameri ...
.[ In Hawaii, the introduction of the ]mosquitofish
The western Mosquitofish (''Gambusia affinis'') is a North American freshwater fish, also known commonly, if ambiguously, as simply Mosquitofish or by its generic name, ''Gambusia'', or by the common name gambezi. Its sister species, the easte ...
(''Gambusia affinis'') was effective in controlling mosquitoes but nearly exterminated the island's endemic damselflies. The ancient greenling '' Hemiphlebia mirabilis'' has been an important flagship species for conservation action in preserving its habitat in Australia.
In culture
''Damselfly'' is a 2005 short film directed by Ben O'Connor. ''Damselfly'' is also the title of a 2012 novel in the ''Faeble'' series by S. L. Naeole, and of a 1994 poem by August Kleinzahler
August Kleinzahler (born December 10, 1949) is an American poet.
Life and career
Until he was 11, he went to school in Fort Lee, New Jersey, where he grew up. He then commuted to the Horace Mann School in the Bronx, graduating in 1967. He wrote p ...
, which contains the lines "And that blue there, cobalt / a moment, then iridescent, / fragile as a lady's pin / hovering above the nasturtium?" The poet John Engels
John Engels (January 19, 1931 South Bend, Indiana - June 13, 2007 Vermont) was an American poet.
Life
John Engels graduated from University of Notre Dame in 1952. After Navy service, Engels studied at the University College, Dublin, then gradua ...
published ''Damselfly, Trout, Heron'' in his 1983 collection ''Weather-Fear: New and Selected Poems''.
Fishing flies
An artificial fly or fly lure is a type of fishing lure, usually used in the sport of fly fishing (although they may also be used in other forms of angling). In general, artificial flies are an imitation of aquatic insects that are natural food ...
that mimic damselfly nymphs are sometimes used in wet-fly fishing, where the hook and line are allowed to sink below the surface.
Damselflies have formed subjects for personal jewellery
Jewellery ( UK) or jewelry (U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a wester ...
such as brooches since at least 1880.
''Damselfly'' is the title of a book by Chandra Prasad that was published in 2018.
See also
*List of damselflies of the world This is a list of damselflies arranged into families.
Family Amphipterygidae
* '' Amphipteryx agrioides''
* '' Amphipteryx longicaudatus''
Family Calopterygidae
:''See List of damselflies of the world (Calopterygidae)''
Family Chlorocyphidae
...
*List of odonates of Sri Lanka
Sri Lanka is a tropical island situated close to the southern tip of India. The invertebrate fauna is as large as it is common to other regions of the world. There are approximately 2 million known species of arthropods, and this number continues ...
References
Sources
*
*
*
*
External links
*
*
Tree of Life: Odonata
on the UF / IFAS Featured Creatures Web site
Minnesota Dragonfly Society: Biology and Ecology
{{Taxonbar , from=Q230502
Insects used as insect pest control agents
Articles containing video clips
Guadalupian first appearances
Extant Permian first appearances
Insect common names