Rhogogaster

Taxonomy

Family: Tenthredinidae
Family common name: common sawflies
Subfamily: Tenthredininae
Tribe: Tenthredinini
Genus: Rhogogaster Konow, 1884
Subgenera: Rhogogaster, Cytisogaster

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 Tenthredininae subfamily are relatively large compared to others in the family, often with distinct colorful markings. Some are wasp-like with black and yellow stripes (Goulet 1992). Many species’ life histories are not known. Some Tenthredininae species feed uniquely, as adults, on flower pollen and other insects (Smith 1993). They can be distinguished from other subfamilies by wing venation (Goulet 1992).

Rhogogaster is a unique sawfly often recognized by large size, angular facial features, and bright green coloring that often fades to light yellow in dead specimens (Benson 1965b, Taeger and Vitsaari 2015).

Diversity

There are 40 described extant species worldwide. Four species occur in North America (Taeger et al. 2010).

Diagnostic characteristics

Subfamily characters

Genus characters

May be confused with

Rhogogaster can be confused with similar species in the subfamily Tenthredininae. It can be distinguished from most other genera by the obtuse angle on the posteroventral area of metepimeron, the ocellar ridge, and the ventral angle of the compound eye. Rhogogaster can be distinguished from closely related Tenthredo by the size of the eye, the apical margin of the labrum, and a lack of furrow on the pronotum (Goulet 1992).

Exotic pest species of concern

none

Host associations

Rhogogaster in North America feed on Filipendula, Stellaria (chickweed), Circaea (enchanter’s nightshade), Populus (poplar), Alnus (alder) and Ranunculus (buttercup) (Goulet 1992).

Life history

Specific biology of this genus is unknown. Some larvae may be polyphagous (Smith 1993). Rhogogaster species are univoltine (Taeger and Vitsaari 2015).

There exist a few records of Rhogogaster adults predating on other insects, including flies and, in one case, Nematinae sawflies (Taeger and Vitsaari 2015).

Distribution

World: The genus is Holarctic, present in North America and Europe, with the most species in Central and East Asia (Taeger et al. 2010, Taeger and Vitsaari 2015).

North America: Rhogogaster occurs in western North America from Alaska and British Columbia south to California, east to the Rocky Mountains, the Great Lakes region, and New York (Ross 1943b).

Map data from: GBIF.org (29 October 2019) GBIF Occurrence Download Rhogogaster

Details about data used for maps can be found here.

Rhogogaster lateraria female lateral habitus; photo by J. Orr, WSDA

Rhogogaster lateraria female lateral habitus; photo by J. Orr, WSDA

Rhogogaster lateraria female face; photo by Q. Baine, WSDA

Rhogogaster lateraria female face; photo by Q. Baine, WSDA

Rhogogaster lateraria male lateral habitus; photo by J. Orr, WSDA

Rhogogaster lateraria male lateral habitus; photo by J. Orr, WSDA

Rhogogaster lateraria male dorsal habitus; photo by J. Orr, WSDA

Rhogogaster lateraria male dorsal habitus; photo by J. Orr, WSDA

Rhogogaster lateraria male face; photo by Q. Baine, WSDA

Rhogogaster lateraria male face; photo by Q. Baine, WSDA

Rhogogaster lateraria fore wing; photo by J. Orr, WSDA

Rhogogaster lateraria fore wing; photo by J. Orr, WSDA