Taxonomy

Lejogaster metallina

Distribution

Species Biology

Preferred environment

Freshwater/wetland; transition mire, fen, marsh, pool and lake edge; along brooks and permanently water-filled ditches in open situations and along brooks in Quercus ilex forest in southern Europe. The predominance of cattle farming in many parts makes this an anthropophilic species in Ireland, because L. metallina is characteristic of unimproved and improved humid grassland, with slow-flowing, canalised brooks in open ditches and shallow, temporary pools and seepages, where its aquatic larvae can develop. It is associated with floating plants like Glyceria fluitans and can tolerate a certain amount of eutrophication. With increased intensification of use of farmland poorly-drained grassland has diminished in frequency, but L. metallina remains one of the most generally-distributed wetland syrphids in Ireland. It is not a species of either bog or conifer plantation, but is found here along brooks and around pools in both fen and deciduous woodland, including wet woodland of Alnus and Salix.

Adult habitat & habits

Humid, seasonally flooded grassland, poorly-drained pasture, beside brooks; flies among low-growing vegetation.

Flight period

May/June (with stragglers in July; also July at higher altitudes) and August/September. Larva: described and figured by Maibach and Goeldlin (1994) and by Hartley (1961); aquatic, occurring among plant roots just at the level of the water surface, along the edge of slowly running water.

Flowers visited

Ranunculaceae; white umbellifers; Cochlearia, Convolvulus, Leontodon, Polygonum, Symphoricarpos, Valeriana.

Irish reference specimens

In the collections of NMI and UM

Determination

van der Goot (1981). The male terminalia are figured by Maibach et al (1994a). The adult insect is illustrated in colour by Bartsch et al (2009b), Stubbs and Falk (1983), Torp (1984, 1994) and van der Goot (1986).

Distribution

World distribution(GBIF)

From northern Fennoscandia and the Faroes (Jensen, 2001) south to Iberia; from Ireland eastwards through Eurasia to the Pacific coast; N Africa. L. metallina is very widespread in Ireland and still frequent, if perhaps less common than in the recent past.

Irish distribution

Recorded as occurring in Ireland in Coe (1953). L. metallina is very widespread in Ireland and still frequent, if perhaps less common than in the recent past.

Temporal change

Records submitted to Data Centre in 2021

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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