Symphyta

Definition

A suborder of Hymenoptera comprising the sawflies and related groups, distinguished from the suborder Apocrita (ants, bees, and wasps) by a broad, unspecialized connection between the thorax and abdomen lacking the narrow 'wasp waist' (petiole). Members typically have two pairs of membranous wings with relatively simple venation, and females often possess a prominent, saw-like ovipositor used to insert eggs into plant tissue. The group includes approximately 8,000 described species across more than 800 genera, with the superfamily Tenthredinoidea being the most diverse.

Etymology

From Greek syn- ('together') + phyō ('grow'), referring to the broadly joined thorax and abdomen.

Example

Larvae of Symphyta such as the pine sawfly (family Diprionidae) feed externally on conifer needles and can cause significant defoliation, whereas most Apocrita larvae are internal parasites or provisioned by adults.

Related Terms

• Apocrita
• sawfly
• Hymenoptera
• petiole
• ovipositor
• Tenthredinoidea
• holometabolous

Usage Notes

Symphyta is a paraphyletic group with respect to Apocrita, meaning the suborder does not include all descendants of its common ancestor. Some phylogenetic studies suggest reclassifying certain symphytan lineages, but the suborder remains in widespread use for practical identification. The name is sometimes used informally as a synonym for 'sawfly,' though technically Symphyta includes several groups (such as horntails and woodwasps in Siricoidea) whose adults do not resemble typical sawflies.