Birka

Taxonomy

Family: Tenthredinidae
Family common name: common sawflies
Subfamily: Selandriinae
Tribe: Aneugmenini
Genus: Birka Malaise, 1944
Subgenera: Birka, Lineobirka

Background

The Tenthredinidae are the most species-rich family and are found throughout the world, in all continents but Antarctica. They are known as the “common sawflies.” They can generally be recognized by a cylindrical body and long, segmented antennae. Otherwise, they come in a variety of colors, sizes, and forms (Goulet 1992).

Sawflies in the Selandriinae subfamily are relatively small and slender. The range of Selandriinae is worldwide; it occurs on all continents except Antarctica (Goulet 1992). It is the most common and diverse group of tenthredinids in tropical regions, particularly in Central America, South America, and Southeast Asia (Smith 1969e). Selandriinae contains the only known sawflies that feed on non-vascular plants, specifically ferns (Smith et al. 2013). The subfamily can be distinguished from other subfamilies by wing venation (Goulet 1992).

Birka is monotypic in North America. Birka nordica is small and stout, about 6 mm in length, and mostly black with some white on the thorax. This species is northern in distribution (Smith 1969e).

Diversity

There are 17 described extant species worldwide. One species occurs in North America (Taeger et al. 2010).

Diagnostic characteristics

Subfamily characters

Genus characters​

May be confused with

Birka can be confused with similar species in the subfamily Selandriinae or tribe Aneugmenini. It can be distinguished from most other genera by the absence of a fore wing anal crossvein, from closely related Aneugmenus by the lack of an occipital ridge, and from Nesoselandria by the malar space length (Smith 1969e).

Exotic pest species of concern

none

Host associations

No hosts are known for North American Birka. Some species in Europe feed on grasses and sedges (Smith 1969e). Uniquely for Selandriinae, some species feed on dicots: B. carinifrons in Japan on Lysimachia spp. (loosestrife), B. cinereipes in Finland on Myosotis spp. (forget-me-not), and B. annulitarsis in Czech Republic on Pulmonaria angustifolia (blue lungwort) (Macek 2013, Shinohara and Ibuki 2017).

Life history

unknown

Distribution

World: This genus is known from North America, Europe, and Japan (Taeger et al. 2010).

North America: Birka nordica occurs in Alaska, Yukon Territory, British Columbia, Alberta, and Manitoba (Smith 1969e).

Map data from: GBIF.org (29 October 2019) GBIF Occurrence Download Birka and the Smithsonian National Museum of Natural History Entomology Collection (USNM)

Details about data used for maps can be found here.

Birka nordica female lateral habitus; photo by J. Orr, WSDA

Birka nordica female lateral habitus; photo by J. Orr, WSDA

Birka nordica female dorsal habitus; photo by J. Orr, WSDA

Birka nordica female dorsal habitus; photo by J. Orr, WSDA

Birka nordica female face; photo by Q. Baine, WSDA

Birka nordica female face; photo by Q. Baine, WSDA

Birka nordica male lateral habitus; photo by J. Orr, WSDA

Birka nordica male lateral habitus; photo by J. Orr, WSDA

Birka nordica male dorsal habitus; photo by J. Orr, WSDA

Birka nordica male dorsal habitus; photo by J. Orr, WSDA

Birka nordica male face; photo by Q. Baine, WSDA

Birka nordica male face; photo by Q. Baine, WSDA

Birka nordica fore wing; photo by J. Orr, WSDA

Birka nordica fore wing; photo by J. Orr, WSDA