Sympetrum striolatum
Sympetrum striolatum (Charpentier, 1840)
Local names: Common darter, Große Heidelibelle, Bruinrode heidelibel, Sympétrum strié, Större ängstrollslända
Species Information
Description
Probably the most widespread and numerous darter in Europe, the archetypical Sympetrum with which all other darters can be compared and that itself can best be identified with exclusion. It is most often confused with S. vulgatum in the north and S. meridionale in the south of its range.
The males are brick red, seldom as deep red as some other species. Their abdomen is rather straight, not very clubbed. The male thorax sides have two yellow bands divided by a reddish brown band. In comparison with S. vulgatum these are more conspicuous. The light bands darken with age and become less obvious but often there are some yellow left at the bottom of the field.
Immature males are yellow and black. The females are also yellowish when teneral but tend to darken with age, even becoming somewhat red.
The following combination of characters is diagnostic in most areas:
- Legs black with a yellow streak along the full length of the tibiae and femora, unlike common species such as S. danae and S. sanguineum.
- Wings at most narrowly yellow at the base, seldom as extensive as on S. sanguineum, let alone S. flaveolum.
- Black base at frons is thick, but not extended downwards along eyes as in S. vulgatum.
Along the Atlantic coast two dark forms near S. striolatum are distinguished that are hardly separable as species. These are S. nigriscens, in parts of Ireland, Britain and Scandinavia, And S. nigrifemur, on Madeira and the Canary Islands. S. nigriscens has by molecular studies been proved to be just a melanic variation of S. striolatum. No genetic studies of S. nigrifemur has yet proved or dismissed its status as a species of its own.
Size
Habitat
In the temperate zone, S. striolatum is found in a wide range of open and sunny standing waters and, less frequently, in habitats with slow-flowing water. In the Mediterranean basin, it is very common on streams which are reduced in summer to narrow running stretches or to residual pools. It is also often found in msn-made habitats and is one of the first species to colonise new ponds and quarries. It occasionally occurs in brackish waters.
Distribution
Sympetrum striolatum is widespread in Eurasia and North Africa, extending eastwards to Japan. In Asia it has a rather southern distribution and has not been recorded from Siberia. Further taxonomic studies may result in some eastern subspecies to gain full species status. The species is common in Turkey and the Levant but in Africa it is confined to the northern Maghreb.
In Europe it is one of the most common and widespread species. Darker specimens found along the Atlantic coast of Ireland, Scotland and Norway were previously assigned to the species S. nigriscens, but is now considered just a melanic variation. The species occurs frequently in the southern quarter of Fennoscandia but seems to be scarce in the Baltic states. Lack of records in Belarus, part of Ukraine and the south of European Russia might origin from the paucity of field studies in this area. However, its absence from the well known southern Urals, indicate that the species is restricted to the warm, southern regions in eastern Europe.
Flight Period
June to November, occasionally in to December or January or even later in areas with warm climates.
Behavior
The males fly to a greater extent than S. vulgatum out over open water and keeps an eye over their territories from vantage points out in or over water. Immature individuals and females can be found far from water and often sit directly on the ground, warming up in the sun. Late in autumn the species still flies and can be seen perching on light trunks or stones.
Females oviposit in flight in vegetation or just below the water surface. She lays her eggs alone or in tandem. Larval development is one year. Exuviae are left low on leaves or straws out in the water or along the shoreline.
On emergence the teneral individuals distance themselves from water and the adults can be best observed starting from late August or September when they return to the reproductive sites.
Conservation Status
Similar Species
Sympetrum meridionale, Sympetrum vulgatum, Sympetrum nigrifemur
External Links
Genus: Sympetrum
Sympetrum is a genus of small to medium-sized skimmer dragonflies, known as darters in the UK and as meadowhawks in North America. The more than 50 species predominantly live in the temperate zone of the Northern Hemisphere. Most Sympetrum fly in late summer and autumn, breeding in ponds and foraging over meadows.
Identification
Rather small libellulids. Mature males, with the exception of a black species, have an abdomen which is a shade of red. Black markings are variable, but usually at least present as traces on the thorax sutures, legs and abdomen. Hindwing base is clear or marked with yellow or amber.
Separation from other genera
The only smaller libellulids without a dark hindwing patch and often a red abdomen in much of our range. Crocothemis legs lack any black and the abdomen is broader (only some Turkish Sympetrum have almost no black on their legs). Red Trithemis are similar in stature but mature males have a much brighter appearance. Brachythemis has a plump, cylindrical abdomen.
Separation of the species
A large and often common genus. Many species can cause identification problems, especially when observing with binoculars only. In most areas, the difficulty will focus on the pair S. striolatum - S. vulgatum, but along the Mediterranean and Atlantic coasts in particular up to four similar species may overlap. These vary in the extent of the black markings, and this has led to taxonomic problems.
Behaviour
All darters behave similarly. They spend most of their time on a prominent perch, from which short dashes are undertaken to chase prey or rivals. Males often attain high densities along the water's edge, defending a small 'private space' around themselves rather than a territory. Oviposition always commences in tandem, but species differ somewhat in their mode of flight and choice of oviposition site.
Family: Libellulidae
The skimmers or perchers and their relatives form the Libellulidae, the largest dragonfly family in the world. It is sometimes considered to contain the Corduliidae as the subfamily Corduliinae and the Macromiidae as the subfamily Macromiinae. Even if these are excluded, there still remains a family of over 1000 species. With nearly worldwide distribution, these are almost certainly the most often seen of all dragonflies.
The genus Libellula is mostly New World, but also has one of the few endangered odonates from Japan: Libellula angelina. Many of the members of this genus are brightly colored or have banded wings. The related genus Plathemis includes the whitetails. The genus Celithemis contains several brightly marked species in the southern United States. Members of the genus Sympetrum are called darters (or meadowhawks in North America) and are found throughout most of the world, except Australia. Several Southern Hemisphere species in the genera Trithemis and Zenithoptera are especially beautiful. Other common genera include Tramea and Pantala.
The libellulids have stout-bodied larvae with the lower lip or labium developed into a mask over the lower part of the face.
The family name may have been derived from the Latin libella which means booklet.