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 antennaeantenna:
the sensory organ emerging from the front of the head, usually between the compound eyes and above the clypeus; includes the flagellum, scape and pedicel
. Otherwise, they come in a variety of colors, sizes, and forms (Goulet 1992Goulet 1992:
Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.).

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 1992Goulet 1992:
Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.). Many species’ life histories are not known. Some Tenthredininae species feed uniquely, as adults, on flower pollen and other insects (Smith 1993Smith 1993:
Smith DR. 1993. Systematics, life history, and distribution of sawflies. Pp. 3-32. In: Wagner MR and Raffa KF, eds. Sawfly Life History Adaptations to Woody Plants. University of Minnesota Academic Press. 581 pp.). They can be distinguished from other subfamilies by wing venationvenation:
the network of veins on a wing
(Goulet 1992Goulet 1992:
Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.).

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 1965bBenson 1965b:
Benson RB. 1965b. The classification of Rhogogaster Konow (Hymenoptera: Tenthredinidae). Proceedings of the Royal Entomological Society of London. Series B: Taxonomy 34: 105-112., Taeger and Vitsaari 2015Taeger and Vitsaari 2015:
Taeger A and Vitsaari M. 2015. European Rhogogaster s. str., with notes on several Asian species (Hymenoptera: Tenthredinidae). Zootaxa 4013 (3): 369-398. http://doi.org/10.11646/zootaxa.4013.3.3).

Diversity

There are 40 described extantextant:
in existence; opposite of extinct
species worldwide. Four species occur in North America (Taeger et al. 2010Taeger et al. 2010:
Taeger A, Blank SM, and Liston AD. 2010. World Catalog of Symphyta (Hymenoptera). Zootaxa 2580: 1-1064.).

Diagnostic characteristics

Subfamily characters

• fore wing fore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  vein M and 1m-cu parallel (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• fore wing fore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  vein R bent at basebase:
  the beginning or most proximal area of any structure
  of veinvein:
  a tube-like, often darkened, structure on the wings
  Sc (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• metepimeron metepimeron:
  the dorsal portion of the metapleuron
  separated from metepisternummetepisternum:
  the ventral portion of the metapleuron
  by distinct furrowfurrow:
  a groove or linear depression
  (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)

Genus characters

• labrum labrum:
  a sclerotized structure on the front of the head between the clypeus and mandibles
  margin straight or slightly emarginated (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• compound eye relatively small; face between eyes slightly visible in laterallateral:
  of or towards the side of the body
  view (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• postocular postocular:
  describes area behind the compound eye
  area about equal to width of compound eye in laterallateral:
  of or towards the side of the body
  view (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• clear occipitalocciput:
  the posterior surface of the head
  ridge extending from mandiblemandible:
  the primary mouthpart used for biting and chewing; jaw
  to near post-ocellar area (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• fore wing fore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  vein 2A+3A complete, connected to 1A by crossveincrossvein:
  short section of wing vein that connects two larger veins
  (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• fore wing fore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  anal crossveinanal crossvein:
  a crossvein that goes through the center of the basal anal cell
  short and close to perpendicular (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• fore wing fore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  vein 2r present (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• fore wing fore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  vein M intersecting Sc+R basalbasal:
  towards the base; closest to the body
  to the intersection of Sc+R and Rs+M (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• angle of fore wingfore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  veins 1m-cu and Cu1 120°–150° (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• fore wing fore wing:
  the anterior wing of each pair of wings; usually the largest wing of the pair
  anal crossveinanal crossvein:
  a crossvein that goes through the center of the basal anal cell
  located in the apicalapical:
  towards the apex; farthest away from the body
  one-third of anal cellanal cell:
  cell A of either the fore wing or hind wing
  (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• metepimeron metepimeron:
  the dorsal portion of the metapleuron
  obtusely angled on lower posterior corner (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)
• distance between cenchricenchrus:
  a sclerotized eliptical lobe on the metascutum used to provide friction with underside of wings to hold them in place on the dorsum of the body while in rest
  3X medial length of postnotumpostnotum:
  posterior section of the notum; also known as the subscutellum
  (Goulet 1992Goulet 1992:
  Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.)

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 posteroventralposteroventral:
describes location towards the back on the underside of the body; posterior and ventral
area of metepimeronmetepimeron:
the dorsal portion of the metapleuron
, the ocellarocellar:
of or pertaining to the ocellus or ocelli
ridge, and the ventralventral:
of or on the underside of the body or structure
angle of the compound eye. Rhogogaster can be distinguished from closely related Tenthredo by the size of the eye, the apicalapical:
towards the apex; farthest away from the body
margin of the labrumlabrum:
a sclerotized structure on the front of the head between the clypeus and mandibles
, and a lack of furrowfurrow:
a groove or linear depression
on the pronotumpronotum:
the anterodorsal part of the thorax, often situated posterior to the head
(Goulet 1992Goulet 1992:
Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.).

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 1992Goulet 1992:
Goulet H. 1992. The genera and subgenera of the sawflies of Canada and Alaska: Hymenoptera. Symphyta. The insects and arachnids of Canada. Part 20. Agriculture Canada Publication.).

Life history

Specific biology of this genus is unknown. Some larvaelarva:
the immature stage of holometabolous insects
may be polyphagouspolyphagous:
feeding upon many different kinds of food
(Smith 1993Smith 1993:
Smith DR. 1993. Systematics, life history, and distribution of sawflies. Pp. 3-32. In: Wagner MR and Raffa KF, eds. Sawfly Life History Adaptations to Woody Plants. University of Minnesota Academic Press. 581 pp.). Rhogogaster species are univoltineunivoltine:
describing an insect with a life cycle of one generation per year
(Taeger and Vitsaari 2015Taeger and Vitsaari 2015:
Taeger A and Vitsaari M. 2015. European Rhogogaster s. str., with notes on several Asian species (Hymenoptera: Tenthredinidae). Zootaxa 4013 (3): 369-398. http://doi.org/10.11646/zootaxa.4013.3.3).

There exist a few records of Rhogogaster adults predating on other insects, including flies and, in one case, Nematinae sawflies (Taeger and Vitsaari 2015Taeger and Vitsaari 2015:
Taeger A and Vitsaari M. 2015. European Rhogogaster s. str., with notes on several Asian species (Hymenoptera: Tenthredinidae). Zootaxa 4013 (3): 369-398. http://doi.org/10.11646/zootaxa.4013.3.3).

Distribution

World: The genus is HolarcticHolarctic:
describing the region of the Northern Hemisphere that includes both the Nearctic and Palearctic regions
, present in North America and Europe, with the most species in Central and East Asia (Taeger et al. 2010Taeger et al. 2010:
Taeger A, Blank SM, and Liston AD. 2010. World Catalog of Symphyta (Hymenoptera). Zootaxa 2580: 1-1064., Taeger and Vitsaari 2015Taeger and Vitsaari 2015:
Taeger A and Vitsaari M. 2015. European Rhogogaster s. str., with notes on several Asian species (Hymenoptera: Tenthredinidae). Zootaxa 4013 (3): 369-398. http://doi.org/10.11646/zootaxa.4013.3.3).

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 1943bRoss 1943b:
Ross HH. 1943b. The Nearctic sawflies of the genus Rhogogaster (Hymenoptera). The Pan-Pacific Entomologist 19 (4): 129-133.).

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

Details about data used for maps can be found here.