Enallagma cyathigerum
Enallagma cyathigerum (Charpentier, 1840)
Local names: Common bluet, Gemeine Becherjungfer, Watersnuffel, Agrion porte-coupe, Sjöflickslända
Species Information
Description
It resembles members of the genus Coenagrion but carries a few recognisable characteristics that differs it. The males are blue with black markings, the blue commonly being more greyish at low temperatures. The side of the thorax is almost completely blue. The interpleural suture on the side of the thorax, typical for Coenagrion sp, is in E. cyathigerum very thin and has no black marking along it. Ischnura sp. has two distictive dots on the side of the thorax, these are also absent on E. cyathigerum. Eyes are clearly blue, in a darker tone than the rest of the body.
Males have a distictive marking on S2, in the shape of a small mushroom (extremely variable). The marking is usually connected to the black ring marking at the end of the segment. The antehumeral stripes are wide.
The females have different colouration, from light blue to brownish, but generally green. Characteristic in females is the presence of a vulvar spine under S8.
Size
Habitat
Enallagma cyathigerum occurs at standing and slow-flowing waters and is especially common at sites lacking fish, such as acidic ponds and bogs, or at sites where belts of vegetation provide shelter from fish. It occurs at brackish waters and is one of several species that commonly reproduces in the Baltic Sea. It is able to endure cold climates, due to which it is not only found in the far north but is also present at high altitudes with populations in the Alps found well over 2 000 m.
Distribution
This species is widespread widespread and common in the European part of its range, where it reaches the far north of Scandinavia. It becomes less frequent towards the Mediterranean, where it has a patchy distribution throughout the most of the Balkan Peninsula and in the driest regions of Spain and Italy, and is rare in large parts of Greece. It is present on only some of the Mediterranean islands including Corsica, Sicily, Crete and several Aegean islands.
Flight Period
May to September
Behavior
The species can be seen in hundreds even at small waters. Both sexes like to perch on waterlilies and pondweeds. Males and females often fly in tandem over open water. Males patrol aggressively over open water in search for females. During oviposition the female immerses her body in the water while the male protects her by flying around her. Especially young individuals can be found far from waters. On windy days large amounts of individuals can be gathered in wind-protected spots near the waters.
Conservation Status
Similar Species
Erythromma lindenii, Coenagrion puella
External Links
Genus: Enallagma
Enallagma is a genus of damselflies in the family Coenagrionidae commonly known as bluets.
Identification
Enallagma males are typically being blue, distinctively marked with black. Females are usually brown or blue, with torpedo-like markings on S3-7. They have a small but prominent vulvar spine at the base of the ovipositor.
Separation from other genera
The blue-and-black pattern of males recalls most Coenagrion species and also Erythromma lindenii. Only Ischnura females share the vulvar spine, although it is weaker on them. Brown females may be confused with Sympecma, which has similar markings on S3-6. However they differ in having long pterostigma and different markings and venation.
Behaviour
Males prefer open water, where they fly and perch on floating plants close to the water surface. Otherwise recalls other Coenagrion species in behaviour.
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 it the largest damselfly family. The family Coenagrionidae has six subfamilies: Agriocnemidinae, Argiinae, Coenagrioninae, Ischnurinae, Leptobasinae, and Pseudagrioninae.
This family is referred to as the narrow-winged damselflies or the pond damselflies. The Coenagrionidae enjoy a worldwide distribution, and are among the most common of damselfly families. This family has the smallest of damselfly species. More than 110 genera of the family Coenagrionidae are currently accepted.
The family was named by William Forsell Kirby in 1890. The name may be derived from Greek coen meaning shared or common and agrio meaning fields or wild.