Erythromma viridulum
Erythromma viridulum (Charpentier, 1840)
Local names: Small red-eyed damselfly, Kleines Granatauge, Kleine roodoogjuffer, Petite demoiselle aux yeux rouges, Mindre rödögonflickslända
Species Information
Description
Males have red eyes, mainly black bodies with sides of the thorax and the last segments on the abdomen light blue. Females green and black, with brown eyes. It could be confused with E. najas but can be distinguished by smaller size, more slender build, antehumeral stripes complete in females and complete or reduced in the males, and by the different extension of the light blue colour on the ventral side of S2-S3 and S8 in the males that also have a distictive black marking in the shape of an X on the last abdominal segment, S10. Also the males have S8 partly blue, rather than completely black in E. najas.
Size
Habitat
Erythromma viridulum is found in largely unshaded, standing or slow-flowing waters with aquatic vegetation, including brackish waters. It often co-occurs with E. najas at habitats with large floating leaves. In contrast to this species, however, it is especially common at waters with rich, fine-leaved, aquatic vegetation such as waterweed, hornworth, watermillfoil and mats of algae on the water surface.
Distribution
The main European range lies in the south and west Europe where the species is common and widespread.An expanson of its range has taken place since the 1970s and has gained some 100-500 km northwards since the 1980s. It was recorded as new to Great Britain (1999), Denmark (2001), Sweden (2004), Belarus (2005) Lithuania (2007) and Latvia (2008). Prior to 1970s it was rare in the Netherlands, but presently the second most common damselfly. This range expansion might be linked with increased temperatures, but the species might also have benefited from nitrogen enrichment of aquatic habitats by aerial deposition. The species has a scattered occurence in parts of the Balkan Peninsula and Ukraine and relatively few records are known from European Russia, probably due to poor sampling.
Flight Period
May to September
Behavior
Much like Erythromma najas it likes to perch on floating vegetation.
Conservation Status
Similar Species
Erythromma najas, Erythromma lindenii
External Links
Genus: Erythromma
Erythromma is a genus of damselfly in the family Coenagrionidae.
Identification
Males of Erythromma species all have bright eyes, some conspicuosly red, some blue. None are capped with black and the top of the eyes contrasts with the black upperside of the head. The postocular spots are reduced to narrow stripes, or are absent. The male black markings on S2 extends all along the segment. No Erythromma males have blue on the upperside of S8, but S9-10 are mostly or completely blue. The blue 'tail-light' is therefore shorter and nearer the tip of the abdomen. The males have much longer upper appendages than lower, they are about as long as S10. The wing tips are usually densely veined, due to numerous cells having been subdivided. This especially in the hindwing. The pterostigma are rather long.
Separation from other genera
Females of Erythromma have no vulvar spine, unlike Enallagma and Ischnura. They have dark eyes, no postocular spots and the entire abdomen upperside is dark.
The blue-bodied E. lindenii was formerly placed in the genus Cercion, but recent studies of DNA, behaviour, and larval and adult morphology places it with Erythromma.
Erythromma males are the only damselflies combining red eyes with blue markings on the body and an all-dark back of head. Males of other blue-tailed damselflies, like Coenagrion, Enallagma, Ischnura, have no red eyes and usually have postocular spots. Most other damselflies with red eyes, like Ceriagrion, Pyrrhosoma, combine this with red bodies. The red-faced male of Pseudagrion sublacteum is likely to be found only in Africa and the Near East.
The combination of characters in Erythromma females may also be found in all-dark forms of Ceriagrion and Pyrrhosoma. These will often have traces of red and have differently configured black markings on the thorax. The legs of Ceriagrion have no black.
If seen well, the males of the two red-eyed species can be identified in the field by details of the blue pattern on the abdomen.
Behaviour
Unlike most other damselflies, males of Erythromma tend to stay away from the water's edge, rather they prefer to perch on floating and emergent structures. Their flight is direct and linear, quickly skimming low over the water's surface.
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.