Neoascia tenur

(Harris, 1780)

Black-kneed Fen Fly

Neoascia tenur is a small Palearctic in the , commonly known as the Black-kneed Fen . The is strongly associated with wetland across northern and central Europe, extending into Siberia. are active from spring through early autumn and visit flowers of wetland plants. The develop sub-aquatically within the stem of emergent aquatic vegetation such as cattails (Typha).

Neoascia tenur by (c) janet graham, some rights reserved (CC BY). Used under a CC-BY license.Neoascia tenur or geniculata - female - Flickr - S. Rae by S. Rae from Scotland, UK. Used under a CC BY 2.0 license.Neoascia tenur (Syrphidae) - (female imago), Elst (Gld), the Netherlands - 4 by This image is created by user B. Schoenmakers at Waarneming.nl, a source of nature observations in the Netherlands. . Used under a CC BY 3.0 license.

Pronunciation

How to pronounce Neoascia tenur: /niːoʊˈæs.i.ə ˈtɛn.jʊr/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from similar Neoascia by the combination of: fore with dark ring, fore yellow with dark (not entirely dark), and relatively narrow in females compared to N. meticulosa. Male require examination for definitive identification; see Barkemeyer & Claussen (1986) and Maibach & Goeldlin (1993) for diagnostic illustrations. The small size and wetland association help separate it from larger .

Images

Appearance

Small with length 3.25–5 mm. Fore with a dark ring. Fore yellow with a dark , remaining tarsal yellowish. Females have a relatively narrow compared to the broader abdomen of N. meticulosa.

Habitat

Wetlands including flushes and streams in blanket bog, raised bogs, fens, wet grassland, pond and lake margins, and along brooks. Strongly associated with standing or slow-moving water with emergent vegetation.

Distribution

Palearctic: Fennoscandia south to Iberia and the Mediterranean basin; Ireland east through Europe into Turkey, European Russia, and Siberia. Presence confirmed in Belgium (Flanders, Brussels-Capital Region, Walloon Region).

Seasonality

period April to September.

Diet

visit flowers including Caltha, Cicuta virosa, Filipendula ulmaria, Potentilla erecta, Ranunculus, and Salix repens. Larval diet unknown; develop within aquatic stems.

Life Cycle

is sub-aquatic, developing within stem of Typha and other water plants. Larvae and described and figured by Maibach and Goeldlin (1993).

Behavior

are flower visitors in wetland . inhabit submerged portions of emergent aquatic plants.

Ecological Role

may contribute to of wetland flowers. Larval role within aquatic not documented.

Similar Taxa

  • Neoascia meticulosaFemales have a broader than N. tenur; leg coloration patterns differ
  • Other Neoascia speciesRequire examination of male and leg coloration patterns for separation

More Details

Taxonomic history

Described by Harris in 1780; male illustrated by Barkemeyer & Claussen (1986); larval and puparial detailed by Maibach & Goeldlin (1993)

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Sources and further reading