Taxonomy
Anasimyia contracta
Distribution
Species Biology
Preferred environment
Wetland; ponds with Typha, especially in fen. In Ireland this species has been found in association with various sorts of standing water wetlands, but a feature common to nearly all the sites involved is the presence of Typha. It has also been reared from larvae collected in Ireland, from under the water-surface, between the stem-sheathing leaf bases of dead Typha in a pond. Freshwater coastal lagoons, fen edging large lakes or small ponds and both limestone lakes and ponds in cut-over valley bog are included. A. contracta has also been found along large, water-filled drainage ditches and can occur in Ireland in association with constructed wetlands, introduced to farmland for treatment of livestock waste. The Irish records are from the period May/August, with the peak in July, suggesting that here there may be but one generation per year, in contrast to the situation over most of Europe.
Adult habitat & habits
Rarely more than a few metres from margins of ponds, where they fly low over the water and settle in the sun, usually on foliage of large-leaved emergent vegetation, such as Menyanthes; they also fly in and out of stands of sedges and reeds, making their movements very difficult to follow.
Flight period
May/June & August/September. Larva: undescribed, but can be found among debris of dead Typha stalks beneath the water surface.
Flowers visited
White umbellifers; Myosotis, Potentilla palustris, Ranunculus, Sorbus aucuparia.
Irish reference specimens
In the collections of NMI and UM.
Determination
Bartsch et al (2009b); Claussen & Torp (1980); Speight (1981b), van der Goot (1981), Verlinden (1991). See Key provided in StN Keys volume. The male terminalia are figured in Claussen & Torp (1980), Torp (1984) and van der Goot (1981). The adult insect is figured in colour in Bartsch et al (2009b), Stubbs and Falk (1983), Torp (1984, 1994) and van der Goot (1986).
Distribution
World distribution(GBIF)
Known from Scandinavia south to the Mediterranean basin and from Ireland eastwards through central Europe to European parts of Russia. A.contracta is an endemic European species that occurs primarily in the Atlantic zone, becoming much more localised in central and southern Europe.
Irish distribution
A.contracta was added to the Irish list by Speight (1981a). Additional Irish records have been published by Anderson (1988) and Nelson (1988). This species was confused with A.transfuga (L.) until its description in 1980, so earlier records of A.transfuga in Ireland (e.g. in Speight et al, 1975) comprise a mixture of A.contracta and A.transfuga records, and cannot be relied upon. A.contracta is widely, but sparcely distributed in Ireland. It is neither common nor threatened here. Elsewhere among the Atlantic seaboard countries of Europe it is more frequent.
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.