sawfly

Symphyta redirects here. For the moth genus, see Symphyta (moth genus).

Sawflies Fossil range: Triassic - Recent
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Suborder:	Symphyta
Superfamilies and families
Superfamily Cephoidea    Family Cephidae (stem sawflies) Superfamily Megalodontoidea    Family Megalodontesidae    Family Pamphiliidae (leaf-rolling & web-spinning sawflies) Superfamily Orussoidea    Family Orussidae (parasitic wood wasps) Superfamily Siricoidea    Family Anaxyelidae (cedar wood wasps)    Family Siricidae (horntails) Superfamily Tenthredinoidea    Family Argidae (argid sawflies)    Family Blasticotomidae (fern sawflies)    Family Cimbicidae (cimbicid sawflies)    Family Diprionidae (conifer sawflies)    Family Pergidae (pergid sawflies)    Family Tenthredinidae (common sawflies) Superfamily Xyeloidea    Family Xyelidae (xyelid sawflies)    Family Xiphydriidae (wood wasps)

Sawfly is the common name for insects belonging to suborder Symphyta of the order Hymenoptera. Sawflies are distinguishable from most other Hymenoptera by the broad connection between the abdomen and the thorax, and by their caterpillar-like larvae. The common name comes from the saw-like appearance of the ovipositor, which the females use to cut into the plants where they lay their eggs. Large populations of certain sawfly species can cause substantial economic damage to forests and cultivated plants.

Taxonomy

Sawfly ovipositing

Sawflies are a group of largely phytophagous (herbivorous) insects. The overall group is paraphyletic, but the name is still in common use, and treated as a suborder, though it seems likely it will be phased out in future classifications. These superfamilies are regarded as the most primitive taxa within the Hymenoptera (some going back 200 million years), and one of the taxa within the Symphyta gave rise to the suborder Apocrita (wasps, bees and ants - this group is considered monophyletic). In the opinion of many experts, the most likely sister taxon to the Apocrita is the family Orussidae, the only Symphytan group which is parasitic.

Larvae

Sawfly (Tenthredo marginella) larva

The larvae look like caterpillars (the larvae of moths and butterflies), with two notable exceptions; (1) they have six or more pairs of prolegs on the abdomen (caterpillars have five or fewer), and (2) they have two stemmata instead of a caterpillar's six. Typical sawfly larvae are herbivorous, the group feeding on a wide range of plants. Individual species, however, are often quite specific in their choice of plants used for food. The larvae of various species exhibit leaf-mining, leaf "rolling", or gall formation. Three families are strictly xylophagous, and called "wood wasps", and one family is parasitic. The larvae that do not feed externally on plants are grub-like, without prolegs.

Adults

larva of Craesus septentrionalis

Adult sawflies, except for those in the family Cephidae, have structures that latch onto the underside of the forewings to help hold the wings in place when the insect is at rest. These "cenchri", which are absent in the suborder Apocrita, are located behind the scutellum on the thorax. Adults of some species are carnivorous, eating other insects, but many also feed on nectar.

See also

Spitfire sawfly

References

• The American Museum of Natural History 2004-01-15
• Kendall Bioresearch Services (Image)

External links

• ECatSym - Electronic World Catalog of Symphyta
• Sawfly - Tenthredininae subfamily - diagnostic photographs and information
• Sawfly - Dolerus unicolor photos and information
• Sawfly - Dolerus nitens photographs
• Sawfly Arge humeralis photographs
• A sawfly injurious to young pines hosted by the UNT Government Documents Department