|Syrphus vitripennis |
Highly variable: boreal, mixed, and deciduous forest, parks, orchards, fields, and vineyards.
Adult flight occurs between May and October across Canada.
Approximately 6 to 14 mm in length, black and yellow body, with eye bare and face yellow. Distinguishing between S. vitripennis and S. ribesii is challenging, however S. ribesii has the bm cell with a small patch devoid of tiny hairs (i.e. not trichose, see A on image) (Gilbert 1986). However, male S. vitripennis are indistinguishable from male S. rectus. Yellow bands on tergites 3 and 4 are complete, curved posteriorly, and cover approximately half of the lateral margins (see B on image). Males: Hind femur is either brown to black, with only the apical one-quarter yellow (Vockeroth 1992).
Syrphus vitripennis is probably multivoltine throughout most of its range, overwintering as a larva. However, there have been records of mass migrations over the Alps for this species, although the purpose of these migrations is unclear, since they occur throughout summer and fall (Schneider 1969). Aphidophagous and polyphagous, it is also an important regulator of natural aphid populations through much of its range. It has also been shown to demonstrate anti-parasitoid behaviours similar to those of S. ribesii (Rotheray 1981). Furthermore, under experimental conditions, S. vitripennis females increased the number of eggs they laid with increased densities of aphid colonies, indicating oviposition site selection for a more reliable food source for their offspring (Wnuk and Starmach 1977).
Common, not of concern.
Larvae have been reported as feeding on Euceraphis sp. (Vockeroth 1992).
Widespread throughout Canada, Alaska south to Colorado and Massachusetts, widespread in Europe and Asia (Vockeroth 1992).
For a clear description of an effective and simple method for rearing S. vitripennis see Frazer (1972).
|species page author||Wins-Purdy, A.||2005 |