Dragonfly Guide

Leucorrhinia

Brittinger, 1850

Leucorrhinia is a genus of dragonfly in the family Libellulidae. They are commonly called whitefaces because of their distinctive pale frons.

Identification

Easily distinguished, even from afar, by their bright white face that is contrasting with their largely black body. This feature is combined with unique wings, having dark spots at the hindwing bases, only 7-8 (rarely 9) forewing antenodal cross-veins and notably short, rectangular pterostigmas. The abdomen is predominantly black, with a single series of pale dorsal spots that either turn deep red in mature males or disappear whilst the abdomen becomes grey pruinose at its base.

Separation from other genera

Other libellulids have coloured faces, although this may be poorly developed in young individuals, and in most of those genera pale colours predominate on the abdomen. Males developing pruinosity (e.g. Orthetrum, Libellula) tend to have this on more than half the abdomen, but the distinction may be difficult in old and worn pruinose Leucorrhinia males. The only largely black libellulid occurring widely with Leucorrhinia species is Sympetrum danae. The smallest species, L. dubia in particular, may be confused with it when viewed from a distance; S. danae has a yellow to black face, and at most a yellow hindwing base. Finally, the white-faced North American vagrant Pachydiplax longipennis may recall a Leucorrhinia species, but it is only likely to appear on the Atlantic seaboard.

Separation of the species

Five species occur in our area. All increase in abundance towards the north-east, ranging deeply into Siberia. Another seven inhabit North America. Our species can easily be separated into two groups. Two species have white appendages and males that become dark, with grey pruinosity at the abdomen base. Three others have dark appendages and develop deep red markings but no pruinosity. Note that the species in these groups often occur together. The white appendages are easily seen from a distance. To identify species, especially the red-spotted ones, examination in the hand might be helpful. The male's hamule and female's vulvar scale rule out all confusion. Young individuals of all species are black with yellowish spots, and can only be separated safely by close examination, and by also referring to the pattern of spots.

Groupspecies
Group 1L. albifrons, L. caudalishas white appendages
Group 2L. pectoralis, L. dubia, L. rubicundahas dark appendages

Behaviour

All species have an erratic flight, especially the smaller red-marked species, which can often be seen dancing over bogs and fens. The larger, pruinose species fly more slowly, often over open water or even among the trees surrounding a breeding site. Females of all species may oviposit alone, or are guarded by the male flying or perching nearby.

Distribution

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Distribution map. Data from gbif.org

Sources

  • Field guide to the dragonflies of Britain and Europe, Klaas-Douwe B Dijkstra.

  • Wikipedia