Taxonomy
Syrphus torvus
Distribution
Species Biology
Preferred environment
Forest; humid conifer forest (Abies, Picea and humid Pinus) and conifer plantations (including exotic genera and species), deciduous forest (Betula, Fagus and acidophilous Quercus) and dwarf-shrub tundra; to some extent anthropophilic, occurring also in suburban gardens with mature trees and in urban parks. This primarily humid forest insect occurs in association with both deciduous woodland (including scrub woodland) and conifer plantation in Ireland. However, S. torvus is not an insect of the standard farmland landscape of green fields and hedges. Its frequency in conifer plantations makes it to a significant extent anthropophilic, a designation reinforced by its occurrence in mature gardens and suburban parks.
Adult habitat & habits
Forest clearings, tracksides etc.; males hover at 2-5m, over tracks, beneath trees etc.
Flight period
March/October, with peaks in mid April/ beginning June and August/September. Larva: described and figured by Dusek and Laska (1964); aphid feeding; occurs on trees, bushes and shrubs. Kula (1982) found larvae of S. torvus at all heights on spruce (Picea) trees in spruce forest and records the larvae as overwintering among leaf litter on the forest floor.
Flowers visited
Umbellifers; Allium ursinum, Aster, Bellis perennis, Brassica rapa, Buxus, Caltha, Cirsium arvense, Crataegus, Euphorbia, Frangula alnus, Glaux maritima, Hedera, Hieracium, Oxalis, Prunus spinosa, Ranunculus, Rosa, Rubus fruticosus, R. idaeus, Salix, Senecio jacobaea, Sorbus, Taraxacum, Tussilago.
Irish reference specimens
In the collections of NMI and UM
Determination
See Key provided in StN Keys volume; Goeldlin (1996), Haarto and Kerppola (2007a), Bartsch et al (2009a). This species has frequently been confused with S. ribesii and S. vitripennis, in European collections. The male terminalia are figured by Dusek and Laska (1964). The adult insect is illustrated in colour by Kormann (1988), Torp (1984, 1994), van der Goot (1986) and Bartsch et al (2009a).
Distribution
World distribution(GBIF)
from Greenland, Iceland, the Faroes (Jensen, 2001) and Fennoscandia south to Iberia and the Mediterranean; through most of Europe into Turkey and European parts of Russia; from the Urals through Siberia to the Pacific coast (Kuril Isles); Japan; Formosa; northern India, Nepal, Thailand; in N America from Alaska south to New Mexico. Elsewhere in Europe, it is frequent except in the south. Its range extends throughout the Palaearctic and into parts of the Oriental and it also occurs extensively in the Nearctic.
Irish distribution
Recorded as occurring in Ireland in Coe (1953). S. torvus is common and widely distributed in Ireland, even if somewhat less frequently encountered than either S. ribesii or S. vitripennis.
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.