Syrphus torvus, the Hairy-eyed Flower Fly, is a common species of hoverfly found in the Holarctic. The adults feed on pollen and nectar, but the larvae feed on aphids.
Description External images. For terminology see Speight key to genera and glossary. Eyes have numerous hairs, in male, long and dense, in female shorter. Femora 3 is black on basal 3/4. The male genitalia and the larva are illustrated by Dusek and Laska (1964).Dusek, J. & Laska, P. (1964). "A contribution to distinguishing the European species of the subgenus Syrphus Fab. (Diptera, Syrphidae) according to the male genitalia and larvae". Acta Soc. Ent. Cechoslov. 61(1): 58-69. See references for determination.Van Veen, M. (2004). Hoverflies of Northwest Europe: identification keys to the Syrphidae. 256pp. KNNV Publishing, Utrecht.addendum.Van der Goot, V.S. (1981). De zweefvliegen van Noordwest - Europa en Europees Rusland, in het bijzonder van de Benelux. KNNV, Uitgave no. 32: 275pp. Amsterdam.Bei-Bienko, G.Y. & Steyskal, G.C. (1988). Keys to the Insects of the European Part of the USSR, Volume V: Diptera and Siphonaptera, Part I. Amerind Publishing Co., New Delhi. .Coe, R.L. (1953). "Diptera: Syrphidae". Handbks. Ident. Br. Insects 10(1): 1-98. R. Ent. Soc. London. pdf.
Distribution Palearctic: Greenland and Fennoscandia southward to Iberia and the Mediterranean basin through Europe into Turkey and European Russia. Also from Urals eastward to Siberia and the Russian Far East to the Pacific coast (Kuril Isles) and Japan. Indomalaya Formosa, Northern India, Nepal, and Thailand.
Nearctic: from Alaska southward to New Mexico.Fauna Europaea.Peck, L.V. (1988). "Syrphidae". In: Soos, A. & Papp, L. (eds.). Catalogue of Palaearctic Diptera 8: 11-230. Akad. Kiado, Budapest. Migratory. Large numbers of hoverflies of this species and of Metasyrphus sp. have been observed on Denali in the Rocky Mountains at altitudes of at the head of the Kahiltna Glacier.
Biology Habitat: Abies, Picea and Pinus forest and Betula, Fagus, Quercus forest and dwarf-shrub tundra. It is synanthropic in suburban gardens with mature trees and in urban parks. Flowers visited include 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, Salix, Senecio jacobaea, Sorbus, Taraxacum, Tussilago.de Buck, N. (1990). "Bloembezoek en bestuivingsecologie van Zweefvliegen (Diptera, Syrphidae) in het bijzonder voor België". Doc. Trav. IRSNB, no. 60, 1–167. It flies March to October. The larva feeds on aphids on trees, bushes and shrubs. Adults feed on pollen and nectar and are particularly attracted to yellow and white flowers. The insect overwinters as larvae.
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