SeasonalityAdult flight period is quite extensive, occurring from April to November.IdentificationApproximately 7 to 15 mm in length, black and yellow body, face yellow. Although S. torvus looks superficially very much like both S. ribesii and S. vitripennis (refer to descriptions for these two species), its distinctive characteristic is that both males and females have hairy eyes. The hairs on the male eyes are denser and longer than those on the female eyes, however this characteristic is quite clear for both sexes (under a microscope). As well, the yellow bands of tergites 3 and 4 are complete, and both sexes have a hind femur that is black for approximately the basal three-quarters (Vockeroth 1992).
Scientific NameSyrphus torvusHabitat
Boreal regions, mixed forest, parks, gardens.
Seasonality
Adult flight period is quite extensive, occurring from April to November.
Identification
Approximately 7 to 15 mm in length, black and yellow body, face yellow. Although S. torvus looks superficially very much like both S. ribesii and S. vitripennis (refer to descriptions for these two species), its…
Approximately 7 to 15 mm in length, black and yellow body, face yellow. Although S. torvus looks superficially very much like both S. ribesii and S. vitripennis (refer to descriptions for these two species), its distinctive characteristic is that both males and females have hairy eyes. The hairs on the male eyes are denser and longer than those on the female eyes, however this characteristic is quite clear for both sexes (under a microscope). As well, the yellow bands of tergites 3 and 4 are complete, and both sexes have a hind femur that is black for approximately the basal three-quarters (Vockeroth 1992).
Life History
Probably multivoltine, with the larva as the overwintering stage. Syrphus torvus is aphidophagous and polyphagous, seeming to prefer shrubs and trees to herbs (Schneider 1969). Sendstad (1976) reported that they…
Probably multivoltine, with the larva as the overwintering stage. Syrphus torvus is aphidophagous and polyphagous, seeming to prefer shrubs and trees to herbs (Schneider 1969). Sendstad (1976) reported that they seem to prefer the vegetation-rich slopes beneath bird cliffs in Spitsbergen, Svalbard.
Conservation
Widespread, not of concern.
Diet InfoSyrphus torvus is entirely aphidophagous, and the larvae have been recorded on the aphids Cinara carolina, and on Euceraphus spp. (Vockeroth 1992). Adults feed on pollen and nectar.
Range
Syrphus torvus is widespread throughout Canada, and from Alaska down to California and Mississippi. It is also found in much of Europe (including as far north as Svalbard), as well as Asia, with records from Siberia…
Syrphus torvus is widespread throughout Canada, and from Alaska down to California and Mississippi. It is also found in much of Europe (including as far north as Svalbard), as well as Asia, with records from Siberia and Nepal (Vockeroth 1992).
Notes
For a clear description of an effective and simple method for rearing S. torvus see Frazer (1972).
//Citation and Rights Box - in-page ?>
Citation
//Citation and Rights Drawer - slide out ?>
Page Citation for Syrphus torvus
Page Citation
"Species Details - Syrphus torvus, University of Alberta E.H. Strickland Entomological Museum." University of Alberta Museums Search Site, https://search.museums.ualberta.ca/g/2-5836. Accessed 13 Apr. 2025.
References
AuthorSendstad, E.
TitleSyrphus torvus Osten Sacken (Dipt., Syrphidae). Records from Spitsbergen, Svalbard.
Publication Date1976
Series TitleNorwegian Journal of Entomology
Volume23
Pages90-91
AuthorFrazer, B. D.
TitleA simple and efficient method of rearing aphidophagous hoverflies (Diptera: Syrphidae).
Publication Date1972
Series TitleJournal of the Entomological Society of British Columbia
Volume69
Pages23-24
AuthorSchneider, F.
TitleBionomics and physiology of aphidophagous syrphidae.
Publication Date1969
Series TitleAnnual Review of Entomology
Volume14
Pages103-124
AuthorVockeroth, J. R.
TitleThe flower flies of the subfamily Syrphinae of Canada, Alaska, and Greenland.
Publication Date1992
Pages362-380
Specimen Information
There are 8 specimens of this Species.
//Map Distribution ?>
8 results plotted on map in 7 markers. Note: Only records with latitude and longitude coordinates are plotted on map.