Taxonomy

Chrysogaster virescens

Distribution

Species Biology

Preferred environment

Forest/wetland; fen carr plus small open areas with flushes and streams in deciduous forest. Most Irish records of this insect are from alongside streams flowing through poorly-drained, scrub-invaded pasture. Other records are from beside streams in Quercus woods, or from scrub and pasture beside lakes. C. virescens is a rather enigmatic species in that only isolated specimens are usually met with.

Adult habitat & habits

Alnus/Salix carr and poorly-drained scrub, streamsides in woodland; settles on foliage of bushes and trees; adults descend to drink from stream margins, in hot weather.

Flight period

End April/mid July. Larva: undescribed.

Flowers visited

White umbellifers, Filipendula, Ilex, Iris, Ranunculus.

Irish reference specimens

In the collections of NMI and UM

Determination

See Key provided in StN Keys volume. Until recently this species has been confused with the very similar C. rondanii Maibach & Goeldlin. The male terminalia are figured by Maibach et al (1994a) and Maibach and Goeldlin (1995). The adult insect is illustrated in colour by Bartsch et al (2009b) and Torp (1994).

Distribution

World distribution(GBIF)

Southern Finland, Ireland, Britain and the Atlantic seaboard of Europe from Denmark to the Pyrenees and northern Spain. Also in Switzerland, in central Europe. It is endemic to Europe and probably has a more restricted world range than any other syrphid known in Ireland - it is archetypally a species of Atlantic parts of Europe, hardly recorded away from the Atlantic zone.

Irish distribution

Given as occurring in Ireland in Coe (1953). C. virescens is not infrequent in Ireland, especially in the west. 

Temporal change

Records submitted to Data Centre in 2024

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References

Publications

Speight, M. C. D. (2008) Database of Irish Syrphidae (Diptera). Irish Wildlife Manuals, No. 36. National Parks and Wildlife Service. Department of Environment, Heritage and Local Government, Dublin, Ireland.

Speight, M.C.D. (2014) Species accounts of European Syrphidae (Diptera), 2014. Syrph the Net, the database of European Syrphidae, vol. 78, 321 pp., Syrph the Net publications, Dublin.

Images