Family: Argidae
Family common name: argid sawflies
Subfamily: Sterictiphorinae
Genus: Aproceros, Malaise, 1931
Subgenera: none


Argidae are found in all non-polar regions of the world (Smith and Middlekauff 1987, Smith 1992). They are external foliage feeders with a wide range of host plants. Additionally, the family exhibits some uncommon behaviors like the excretion of defensive compounds and subsocial habits (Smith 1992).

Aproceros is represented in North America by a single species, which is a major forestry pest (Martel 2020). Aproceros leucopoda is black and brown with yellow and white legs and darkened wings (Blank et al. 2010a).


There are 10 described species worldwide, generally restricted to Asia. Only one species is known in North America (Taeger et al. 2010, Blank et al. 2014).

Diagnostic characteristics

May be confused with

The family Argidae can be distinguished by the single-segmented flagellum of the antenna. Aproceros leucopoda females can be distinguished from Arge by the lack of preapical spurs on the tibiae, and an open cell R and a lack of vein Sc in the fore wing. It can be distinguished from Sphacophilus, Sterictiphora, and Aprosthema by the lack of an anal cell in the hind wing (Smith 1992, Blank et al. 2010a).

Exotic pest species of concern


Host associations

Larvae are external leaf feeders on various species species of elms. The larvae discovered in North America was found on Ulmus americana (American elm) (iNaturalist). In Europe, it is recorded on Ulmus pumila (Siberian elm), U. glabra (wych elm) and U. procera (field elm) (Blank et al. 2014).

Life history

Aproceros leucopoda is commonly known as the “elm zigzag sawfly” due to its unusual larval feeding behavior. Females deposit eggs on the margin of leaves. The hatched larva eats the leaf issue from outside edge inwards, going back and forth to create zig-zag cutouts, similar to the wider winding cutouts left by some species of Sterictiphora. As the larvae mature, they transition to feeding on the entire leaf, sometimes leaving only the midvein. The prepupa forms a cocoon on the underside of the remaining leaf (Doychev 2015, Martel 2020). The success of A. leucopoda as a pest is credited to its short life cycle (egg to adult in less than a month), multiple generations per year, cold tolerance, and parthenogenetic reproductive capabilities (Martel 2020, Vétek et al. 2020).


World: Aproceros is a genus native to East Asia and ranges as far east as Japan and as far south as southern China (Blank et al. 2010a, Taeger et al. 2010). Introduction of Aproceros leucopoda was first observed in Europe in 2003 and has since been observed in Austria, Hungary, Poland, Romania, Slovakia, Ukraine, Germany, Belgium, the Netherlands, Russia, Moldova, Slovenia and Italy (Blank et al. 2010a, Blank et al. 2014).

North America: A. leucopoda is introduced in North America and was first observed in Quebec, Canada in 2020 (Martel 2020).

Map data from: GBIF.org (28 December 2020) GBIF Occurrence Download Aproceros

Details about data used for maps can be found here.

Specimens of this species not available for imaging.