Saw Flies

Don Herbison-Evans
Stella Crossley

(updated 28 March 2010)

(Photo: courtesy of Lynette Queale, South Australia)

Sawfly larvae of some species are green, some black, others brown or off-white, and some are striped, and some are spotted.

Some have brown heads, others black. Some have blunt tails, some pointed. Some have white tails, some black.

(Photo: courtesy of Paula Sjostedt, Eungella, north Queensland)

Different species feed on plants from different families. Different species vary in size, some growing to a length of about 5 cms.

The larvae of some are species are solitary.

(Photo: courtesy of Gary Jamieson,
taken at Banyule Flats Parklands, Rosanna, north of Melbourne)

The larvae of other sawfly species are so gregarious that they are often found in a knotted ball of many individuals. When disturbed, they all wriggle their tails and exude a nasty brown fluid from their mouths. This latter habit has given them the common name of “Spitfires”, although they do not actually spit the fluid, just dribble it. They use the tapping of their tails to communicate with each other.

Photo: courtesy of Alicia Johnston,
taken at Serendip Wildlife sanctuary, Lara, south west of Melbourne.

Sawfly larvae are not true Caterpillars, but are the larvae of various species of wasps. They have 3 pairs of true legs, and up to 8 pairs of prolegs (true caterpillars only have up to 5 pairs of prolegs).

Photo: courtesy of Barb Evans,
Eurobin, Victoria.

Some pupate in a cocoon, and some pupate naked, Typically they pupate in the leaf litter, and the pupal duration can be up to two years.

adult sawfly of the speciesPerga dorsalis.

An adult wasps of different species vary in wingspan from 1 cm. to 4 cms. Different species have various colour schemes, including black, white, brown, and orange, and some have the odd coloured spot and/or abdominal bands. The female of many species lays her eggs in a slit she cuts between the upper and lower skins a leaf of a food plant: an amazing feat of dexterity.

The larvae and adults of this family are quite harmless to people. They do not sting, unlike their cousins the communal wasps. Saw Flies are found all over the world, for example :

Common species in Australia include:

imageCaliroa cerasi, TENTHREDINIDAE

imageLophyrotoma zonalis, PERGIDAE,

imagePerga dorsalis, PERGIDAE,

imagePhilomastix xanthophilus, PERGIDAE.

imagePterygophorus cinctus, PERGIDAE.

Further reading :

Greg Pyers,
Insects, Reed International Books Australia, Port Melbourne, 1999, pp. 5,10-11.