Taxonomy

Eristalis cryptarum | Bog Hoverfly

Distribution

Species Biology

Preferred environment

Wetland/freshwater; palsa mires, pools or spring-fed streamlets in tundra, at the edge of raised bogs, in poor fen and marsh (including alpine floodplain marsh) and wet flushes in moorland; taiga wetlands. No habitat information is provided on the data labels of any of the Irish specimens available in collections. But the general character of the landscape in the vicinity of the localities from which those specimens were derived gives no obvious indication that E. cryptarum required habitat conditions in Ireland that were markedly different from those it uses elsewhere. All that can be said in this context is that it seems to have been associated with small, clear, ground-water water bodies like flushes and streams - susceptible to both drainage and pollution.

Adult habitat & habits

Near oligotrophic and mesotrophic pools and streamlets; flies fast over ground vegetation, zig-zagging around stands of plants in flower.

Flight period

Mid May/mid September (Stubbs and Falk, 1983, give March/September), with most records from June. Divoltine in lowland or southern latitudes, but univoltine further north or at higher altitudes, where it is in flight end June/August. Larva: undescribed. According to Stubbs and Falk (2002) the female has been observed ovipositing on and close to very fresh cow dung along oligotrophic seepages in moorland. The morphology of the chorion of the egg is figured by Kuznetzov (1988).

Flowers visited

Yellow composites and crucifers; Calluna vulgaris, Caltha, Cardamine, Menyanthes, Potentilla erecta, P. palustris, Ranunculus, Succisa, Sorbus aucuparia, Vaccinium. Drake (2005), who carried out a study specifically on flower-visiting by E. cryptarum, added Anagallis and Narthecium to the list of flowers at which this hoverfly feeds.

Irish reference specimens

In the collections of NMI

Determination

See Key provided in StN Keys volume and Hippa et al (2001), who figure the male terminalia. Bartsch et al (2009b), Stubbs and Falk (1983), Torp (1984, 1994) and van der Goot (1986) illustrate the adult insect in colour. The male terminalia are figured in Kanervo (1938). Hippa et al (2001) regard nigritarsis Macquart as a junior synonym of this species.

Distribution

World distribution(GBIF)

Northern Fennoscandia south to the Pyrenees; from Ireland (extinct) through central Europe into Russia and on into central Siberia; Mongolia.

Irish distribution

Recorded as occurring in Ireland in Coe (1953). E. cryptarum has not been recorded in Ireland for more than 50 years, despite the increase in attention received by syrphids here over the last 25 years, and has to be regarded as extinct. But, in case it survives as yet undetected, it should be included in any listing of insects requiring protection at national level. The disappearance of this insect from Ireland parallels what has been observed elsewhere, in lowland parts of western Europe, and E. cryptarum is now virtually extinct in the land south from Scandinavia to the Pyrenees (except for parts of the Massif Central in France, where it is not infrequent in high altitude wetlands) and east of mountainous parts of central Europe. It is also apparently extremely localised in the Alps.

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.

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