''Enallagma cyathigerum'' (common blue damselfly, common bluet, or northern bluet) is a species found mainly between

latitudes 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 ...

40°N and 72°N; It is widely distributed in the

Palearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

, and the

Nearctic The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...

species '' Enallagma annexum'' was at one time considered to be synonymous with it. The species can reach a length of 32 to 35 mm (1.3 to 1.4 in). It is common in many different countries including

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...

, the

United States of America The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ...

, and

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...

Damselflies Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies, which constitute the other odonatan suborder, Anisoptera, but are smaller and have slimmer bodies. Most species fold the wings along ...

are an important link between the health of the

aquatic ecosystem An aquatic ecosystem is an ecosystem formed by surrounding a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. The tw ...

and its response to

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

Habitat

These damselflies inhabit

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

bodies whose conditions range, they have been seen in acidic

fens A fen is a type of wetland. Fen, Fenn, Fens, Fenns, may also refer to: People * Fen (name), a Chinese given name and surname * Fen Cresswell (1915–1966), New Zealand cricketer * Fen McDonald (1891–1915), Australian rules footballer * Kees ...

as well as

eutrophic Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplank ...

ponds 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 ...

. They have been considered one of the more sensitive insects in an aquatic setting. They are important within the

trophic levels The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it i ...

as they are an intermediate

predator 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 ...

. They consume smaller

larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

and they are preyed on by fish and larvae bigger than them. The larvae prefer a habitat that has a more complex structure in the ground composition as well as the plants. The larval stages spend most of their time within the plants, climbing and feeding. Although they do prefer a more complex habitat, they can also be found in habitats with simpler vegetation. They are efficient in both complexities equally, but the complex vegetation also serves as protection from fish. These larvae are able to live in a dense population in shallow areas of water without showing signs of competition between the larvae. The damselfly larvae require a plant structure that can withstand the backward movement that occurs when the labium protracts to catch food.

Identification

The males of this species are a

cerulean blue Cerulean (), also spelled caerulean, is a shade of blue ranging between azure and a darker sky blue. The first recorded use of ''cerulean'' as a colour name in English was in 1590. The word is derived from the Latin word '' caeruleus'', "da ...

color with black markings, while the females have a larger variation in their coloring. Within females there are a few different morphs in which they can take, andromorph and heteromorph. Andromorphic females resemble the cerulean blue males, but they have more black patterning on their bodies. The heteromorphic females are more of a brown or green brown color and do not resemble the males at all. The reasoning behind the different morphs is to attempt to limit the amount of attention the female receives when she is near the water for reproduction. The common blue damselfly can be easily mistaken for the azure damselfly (''

Coenagrion puella The azure damselfly (''Coenagrion puella'') is a species of damselfly found in most of Europe. It is notable for its distinctive black and blue colouring. They are commonly found around ponds and lakesides during the summer. Morphology Adults ...

''), but on the back and the

thorax 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 cre ...

, the common blue damselfly has more blue than black; for the azure damselfly it is the other way around. The second segment of the thorax has a distinctive spot with a line below connecting to the third segment. Another difference can be observed when inspecting the side of the thorax. The common blue damselfly has only one small black stripe there, while all other blue damselflies have two.

Lifecycles

The lifecycle of this species begins in freshwater, they spend most of their time as larvae. The larval stage depends on the temperature, light, and the resource level. Once the temperatures drop the larvae can go into a state called

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

instead of dying. The damselflies that endure diapause effect the body size for the next season. Since these damselflies are flexible, they have two different lifecycles depending on latitude

univoltine 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. ...

or semivoltine. The more north these damselflies are found, the more likely they are to be semivoltine. By being able to shift the lifecycle due to the conditions this allows for twice the amount of development time, so larger adults are typically found in more northern areas. Once the larvae emerge as adults between May to August they have a brief time to feed before they are to find a mate and reproduce the next generation of larvae. Once emerged, there is an estimated

sex ratio The sex ratio (or gender ratio) is usually defined as the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. Many species devia ...

of 1:1 within the colony, allows for mating within the colony to be less of a competition. During mating, the male clasps the female by her neck while she bends her body around to his reproductive organs – this is called a mating wheel. The pair flies together over the water and eggs are laid within a suitable plant, just below the surface. The eggs hatch and the larvae, called nymphs, live in the water and feed on small aquatic animals. Nymphs climb out of the water up a suitable stem to molt into damselflies.

Behaviour

All ''Coenagrionid'' larvae have a broad range in diet, so they can live in many different habitats. The larvae are able to eat relatively large prey items, but the prey are typically less mobile and therefore easier to catch. The males in the colony show a higher mobility level compared to other species. There has also been pairings with '' Ischnura elegans'' and ''

'' which are similar to '' Enallagma'', although this occurs when there is same species mates are unable to be located. This damselfly requires a close look for a beginner to distinguish them from an

azure damselfly The azure damselfly (''Coenagrion puella'') is a species of damselfly found in most of Europe. It is notable for its distinctive black and blue colouring. They are commonly found around ponds and lakesides during the summer. Morphology Adults ...

. Typically, they fly low through the reeds and often fly well out over the water, unlike azure damselflies. They are also a brighter blue.

Mitogenome

The mitogenome was

sequenced In genetics and biochemistry, sequencing means to determine the primary structure (sometimes incorrectly called the primary sequence) of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which suc ...

for this species. The circular DNA sequence is 16,661

base pairs A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

long. Within 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 ...

'' it is one of the largest mitogenomes to be sequenced thus far. The composition of the sequence is 74.2%

adenine Adenine () ( symbol A or Ade) is a nucleobase (a purine derivative). It is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The three others are guanine, cytosine and thymine. Its derivati ...

and

thymine Thymine () ( symbol T or Thy) is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The others are adenine, guanine, and cytosine. Thymine is also known as 5-methyluracil, a pyrimidine nu ...

and 25.8%

cytosine Cytosine () ( symbol C or Cyt) is one of the four nucleobases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an am ...

and

guanine Guanine () ( symbol G or Gua) is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine (uracil in RNA). In DNA, guanine is paired with cytosine. The guanine nucleoside is called ...

. This knowledge assists with the placement within a

phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

Human impacts

Pesticides Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampric ...

have a large impact on this species due to its sensitivity. These pesticides are introduced to the water by

runoff Runoff, run-off or RUNOFF may refer to: * RUNOFF, the first computer text-formatting program * Runoff or run-off, another name for bleed, printing that lies beyond the edges to which a printed sheet is trimmed * Runoff or run-off, a stock market ...

and by being added directly. Being exposed to pesticides made these organisms less likely to be successful in

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 ...

with the effects being worse the longer the organism is exposed. The exposure to the larvae has effects on the adult life stage in regard to their fitness Behaviour is lessened by the introduction of pesticides.

Gallery

File:Enallagma cyathigerum 5(loz).jpg, Distinctive marking at base of abdomen of male segment S2 File:Common blue damselfly (Enallagma cyathigerum) male dark variant.jpg, Adult male, dark variant of S2 File:Common blue damselfly (Enallagma cyathigerum) male.jpg, Adult male File:Common blue damselfly (Enallagma cyathigerum) heterochrome female 2.jpg, Heterochrome female File:Common blue damselfly (Enallagma cyathigerum) heterochrome female (green variety).jpg, Heterochrome female (green variety) File:Common blue damselflies (Enallagma cyathigerum) (heterochrome female) in tandem.jpg, In tandem
(heterochrome female) File:Common blue damselflies (Enallagma cyathigerum) (homochrome female) in tandem.jpg, In tandem
(homochrome female) File:Common blue damselflies (Enallagma cyathigerum) female dull green form mating wheel.jpg, Mating wheel
(female dull green form) File:Enallagma cyathigerum - 2013-08-22.webm, Oviposition on ''

Marsilea quadrifolia ''Marsilea quadrifolia'' is a herbaceous plant found naturally in central and southern Europe, Caucasia, western Siberia, Afghanistan, south-west India, China, Japan, and Vietnam, though it is considered a weed in some parts of the United State ...

References

External links

*
Bugguide.net page on ''Enallagma'' damselflies

Youtube video of ''E. cyathigerum''
{{Taxonbar, from=Q608908 Coenagrionidae Damselflies of Europe Insects described in 1840 Odonata of Asia Odonata of North America Taxa named by Toussaint de Charpentier Articles containing video clips