Xiphydria

Taxonomy

Family: Xiphydriidae
Family common name: xiphydriid woodwasps
Subfamily: Xiphydriinae
Genus: Xiphydria Latreille, 1803
Subgenera: none

Background

Xiphydriidae is a small but widespread family. Though sawflies are generally considered plant pests, xiphydriids feed only on already dead or dying wood. Species in the genus can become secondary pests of raw woodworking materials, but usually are of little economic importance. They are often found by humans in firewood (Smith 1976c).

Xiphydria is the only North American genus of the family. They are slender and wasp-like with distinctive spherical heads and relatively small eyes. Larvae feed on wood of deciduous trees (Smith 1976c).

Diversity

There are 35 described species worldwide restricted to the Northern Hemisphere. Eleven species occur in North America, including one introduced from Eurasia (Taeger et al. 2010).

A key to the North American species of Xiphydria is included in Smith 1976c.

Diagnostic characteristics

May be confused with

Xiphydriidae can be separated from other sawfly families by the “neck” and narrowly constricted pronotum. Xiphydria is the only genus of this family in the Nearctic (Smith 1976c).

Exotic pest species of concern

Xiphydria has a large variety of host plants that occur throughout the Northern Hemisphere, so a potential introduction can likely lead to establishment. Though this genus is a secondary pest and usually not the cause of mortality of trees, the feeding habits can lead to loss of the value of wood products, having a noticeable economic impact. Xiphydria longicallis has caused economic damage to oak wood in Europe. This species is known from central and southern Europe and recently spread to the British Isles (Shaw and Liston 1985, Führer 1998).

Host associations

Larvae feed on wood of a large variety of broadleaf trees, including species of Acer (maple), Betula (birch), Ulmus (elm), Carya (hickory), Populus (cottonwood), Salix (willow), Alnus (alder), Platanus (sycamore, plane), Rhus (sumac), Fagus (beech), Fraxinus (ash), Tilia (basswood), Ostrya (hophornbeam), Crataegus (hawthorn), Carpinus (hornbeam), Prunus (cherry, plum), and Quercus (oak) (Smith 1976c, Smith 1983, Goulet 1992).

Life history

Females oviposit eggs into diseased or dead wood, usually in fallen branches or widow-makers. The egg is deposited along with a symbiotic fungus that begins to break down the surrounding wood. Larvae are white and grub-like in appearance, very similar to fellow wood-borers in the Siricidae. Larvae bore galleries into the wood, parallel to the grain, packing frass behind its body as it feeds. At maturity, the prepupa turns and directs the gallery in a 90-degree angle towards the outside of the branch and then pupates, so that only a small amount of wood is left to chew through for the adult after metamorphosis. Emergence holes are about 3 mm in diameter. Xiphydria is univoltine (Smith 1976c, Deyrup 1984, Smith and Schiff 2001).

Distribution

World: This genus has a Holarctic range and is common in Europe and Asia (Shaw and Liston 1985, Taeger et al. 2010).

North America: Xiphydria is known from mainly from northeastern and midwestern United States and eastern Canada (Smith 1976c). Xiphydria prolongata was introduced and is adventive in North America, first found in Michigan in 1980 (Smith 1983).

Map data from: GBIF.org (26 June 2019) GBIF Occurrence Download Xiphydria

Details about data used for maps can be found here.

Xiphydria prolongata female lateral habitus; photo by Q. Baine, WSDA

Xiphydria prolongata female lateral habitus; photo by Q. Baine, WSDA

Xiphydria prolongata female dorsal habitus; photo by J. Orr, WSDA

Xiphydria prolongata female dorsal habitus; photo by J. Orr, WSDA

Xiphydria prolongata female face; photo by J. Orr, WSDA

Xiphydria prolongata female face; photo by J. Orr, WSDA

Xiphydria mellipes male lateral habitus; photo by J. Orr, WSDA

Xiphydria mellipes male lateral habitus; photo by J. Orr, WSDA

Xiphydia mellipes male dorsal habitus; photo by J. Orr, WSDA

Xiphydia mellipes male dorsal habitus; photo by J. Orr, WSDA

Xiphydria mellipes male face; photo by J. Orr, WSDA

Xiphydria mellipes male face; photo by J. Orr, WSDA

Xiphydria mellipes fore wing; photo by J. Orr, WSDA

Xiphydria mellipes fore wing; photo by J. Orr, WSDA

Xiphydria prolongata female head; photo by Q. Baine, WSDA

Xiphydria prolongata female head; photo by Q. Baine, WSDA

Xiphydria mellipes male mandibles; photo by J. Orr, WSDA

Xiphydria mellipes male mandibles; photo by J. Orr, WSDA

Xiphydria mellipes male lateral propleuron; photo by J. Orr, WSDA

Xiphydria mellipes male lateral propleuron; photo by J. Orr, WSDA

Xiphydria mellipes male ventral propleuron; photo by J. Orr, WSDA

Xiphydria mellipes male ventral propleuron; photo by J. Orr, WSDA