Dolerus

Dolerus

Dolerus is for the large part a temperate and subarctic genus. Formerly the genus was split into two genera: Lodolerus and Dolerus. The genus is readily recognised from the forewing venation having a strongly curved vein Rs+M on cell 1R1 and the absence of vein 2r-m between cells 1RS and 2RS. All species are black, or marked with red on the thorax, abdomen and or legs. Some species are variable and may be wholly black or marked with red to varying extents.

Larvae are solitary feeders hiding at the base of the plant and climbing up the stem to feed in low light levels. Larvae can be spilt into grass feeders in drier habitats and rush, sedge or horsetail feeders in wetter habitats. Several of the grass feeding species can be a pest in cereal crops. Dolerus species overwinter in a pupal state rather than a pre-pupal state that is usual in the majority of sawflies. They pupate in soil in excavated cavities without any structural cocoon.

There are at least 120 species worldwide, of which 35 occur in Britain and 20 in Ireland.

Whilst species exhibit some colour variation and may of course be found in differing locations, there division by habitat and colour scheme can be an aid towards identification.

Drier grassland
habitats:

 

Entirely black species:

Dolerus aeneus Hartig, 1837

Dolerus anthracinus (Klug, 1818)

Dolerus asper Zaddach, 1859

Dolerus brevicornis Zaddach, 1859

Dolerus fumosus Stephens, 1835

Dolerus niger (Linnaeus, 1767)

Dolerus nigratus (Müller, 1776)

Dolerus nitens Zaddach, 1859

Dolerus picipes (Klug, 1818)

Dolerus possilensis Cameron, 1882

Dolerus varispinus Hartig, 1837

 

Species with red on the thorax or abdomen:

Dolerus haematodes (Schrank, 1781)

 

Species with only the legs marked with red:

Dolerus gonager (Fabricius, 1781)

Dolerus liogaster Thomson, 1871

Dolerus puncticollis Thomson, 1871

Dolerus schmidti Konow, 1884

Wetter rush, sedge
and horsetail habitats:

 

Entirely black species:

Dolerus asper Zaddach, 1859

Dolerus coracinus (Klug, 1818)

Dolerus harwoodi Benson, 1947

Dolerus pachycerus Hartig, 1837

Dolerus possilensis Cameron, 1882

Dolerus pratensis (Linnaeus, 1758)

Dolerus stygius Förster, 1860

 

Species with red on the thorax or abdomen

Dolerus aericeps Thomson, 1871

Dolerus anticus (Klug, 1818)

Dolerus bimaculatus (Geoffroy, 1785)

Dolerus cothurnatus Serville, 1823

Dolerus ferrugatus Serville, 1823

Dolerus germanicus (Fabricius, 1775)

Dolerus gessneri André, 1880

Dolerus gilvipes (Klug, 1818)

Dolerus haematodes (Schrank, 1781)

Dolerus madidus (Klug, 1818)

Dolerus pratensis (Linnaeus, 1758)

Dolerus pratorum (Fallén, 1808)

Dolerus triplicatus (Klug, 1818)

Dolerus vestigialis (Klug, 1818)

Dolerus yukonensis Norton, 1872

 

Species with only the legs marked with red:

Dolerus eversmanni Kirby, 1882

Dolerus gessneri André, 1880

Dolerus vestigialis (Klug, 1818)

References:

Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London

Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168. https://doi.org/10.3897/BDJ.2.e1168