Pseudosiobla

Taxonomy

Family: Tenthredinidae
Family common name: common sawflies
Subfamily: Allantinae
Tribe: Eriocampini
Genus: Pseudosiobla Ashmead, 1898
Subgenera: none

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 Allantinae subfamily are mostly black and shining, sometimes with other colors. They have agricultural importance as some species are pests on cultivated and ornamental plants (Smith 1979a). They can be distinguished from other subfamilies by wing venation (Smith 2003a).

Pseudosiobla are relatively large, about 8–10 mm in length. All North American species are mostly black with color on the basal abdominal tergites and pronotum, and have stout antennae (Smith 1979a).

Diversity

There are two described extant species worldwide; both are Nearctic (Taeger et al. 2010).

A Nearctic key to species is included in Smith 1979a.

Diagnostic characteristics

Subfamily characters

Genus characters​

May be confused with

Pseudosiobla can be confused with similar species in the subfamily Allantinae or tribe Eriocampini. It can be distinguished by the straight margin of the clypeus, the absence of vein Rs, and the absence of a complete genal ridge (Smith 1979a).

Exotic pest species of concern

none

Host associations

In North America, Pseudosiobla feeds on Cephalanthus spp., including C. occidentalis (buttonbush) (Smith 1979a).

Life history

The female Pseudosiobla lays eggs into the dorsum of the leaf of the host plant. Larvae are light green-gray with pairs of brown spots on each segment. The larvae feed singly on the underside or edges of the leaves. At maturity they drop to the ground and build cocoons with dirt and sand, where they overwinter. Adults emerge in late spring/early summer. Pseudosiobla excavata is univoltine (Smith 1979a).

Distribution

World: This genus is known only from North America (Taeger et al. 2010).

North America: Pseudosiobla species occur in the eastern United States, from as far west as Texas, to Florida and New England on the Atlantic coast (Smith 1979a).

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

Details about data used for maps can be found here.

Pseudosiobla excavata female lateral habitus; photo by J. Orr, WSDA

Pseudosiobla excavata female lateral habitus; photo by J. Orr, WSDA

Pseudosiobla excavata female dorsal habitus; photo by J. Orr, WSDA

Pseudosiobla excavata female dorsal habitus; photo by J. Orr, WSDA

Pseudosiobla excavata female face; photo by Q. Baine, WSDA

Pseudosiobla excavata female face; photo by Q. Baine, WSDA

Pseudosiobla excavata male lateral habitus; photo by J. Orr, WSDA

Pseudosiobla excavata male lateral habitus; photo by J. Orr, WSDA

Pseudosiobla excavata male dorsal habitus; photo by J. Orr, WSDA

Pseudosiobla excavata male dorsal habitus; photo by J. Orr, WSDA

Pseudosiobla excavata male face; photo by Q. Baine, WSDA

Pseudosiobla excavata male face; photo by Q. Baine, WSDA

Pseudosiobla excavata fore wing; photo by J. Orr, WSDA

Pseudosiobla excavata fore wing; photo by J. Orr, WSDA