Sawflies, Spitfire Grubs - Suborder Symphyta, family Pergidae
- Sawfly larvae, body length 30mm
- Sawflies are closely related to wasps, bees and ants. They are grouped in the same insect order Hymenoptera. The common name 'Sawflies' is misleading. They are not flies. They got their common name because the female have their special egg-laying tool, like a saw, to cut through leaf tissue for their eggs. Adults look similar to wasps except they do not have the narrow 'waist'. Sawflies do not sting. They do not form the social organization like wasps, bees or ants, but their larvae do stay together for the defence.
- Sawfly larvae are sometimes seen on trees and shrubs, more commonly seen than adults. Sawfly larvae are vegetarians and feed on leaf. Unlike other members in the order Hymenoptera, Sawfly parents do not provide parental care to their young, except they lay them on the suitable food plants and some species guard their eggs until they hatch. It is believe that the ancestor of hymenopterans, i.e., ants, wasps, and bees, look like the Sawflies. The larvae of Sawflies are look similar to the moths or butterflies caterpillars but they have six or more pair of prolegs while caterpillars usually have five pairs or less.
- Adult sawflies do not sting. However, the larvae may secrete irritating liquid onto the skin or eyes if disturbed.
- Some Sawfly larvae are commonly called Spitfire Grubs. They feed on Eucalyptus and Angophora and
store Eucalyptus oil inside body used for deference.
When disturbed, larvae tap their abdomens up and down and regurgitate the Eucalyptus oil
as thick yellow fluid.
Sawflies are in the same order Hymenoptera as ants, bees and wasps. Those are placed in suborder Apocrita while Sawflies are placed in a suborder Symphyta. They are only a few families in the Sawfly suborder. Most sawflies found in Australia are in family Pergidae.
This page contains pictures and information about Sawflies that we found in the Brisbane area, Queensland, Australia. Their larvae are commonly called Spitfire Grubs.
- Subfamily Perginae
- Adults and larvae in Perginae are large in size. Larvae do not have the abdominal prolegs. They feed on Eucalyptus and Angophora and store Eucalyptus oil inside body used for deference. They aggregate on leaves, branches or trunks by days, disperse and feed during the night. They pupate in soil and litter.
- Subfamily Pterygophorinae
- Sawflies in the Pterygophorinae subfamily are usually banded with bright colours, either orange and yellow, with darken wings. Some species males have comb-like antenna. Larvae in this subfamily feed on leaves of different native plants. They have six or more pairs of prolegs and a "tail" on the last segment. They do not aggregate in large group. They feed actively in small group during the day.
- Subfamily Philomastiginae
- Females of Philomastiginae stand guard over eggs and young larvae. They buzz their wings and stridulate when disturbed. Philomastix sp. larvae have two "tails".
- Subfamily Styracotechyinae
- We found only one species in this subfamily.
- Sawfly Larvae and Tachinid Fly
- ? sp., larvae length 5mm
- The above pictures show a Tachinid Fly checking the sawfly larvae and about to lay eggs on the larvae. The white eggs of the fly will attach on the body of the larva. The egg hatches into maggot and bores into the body, develops inside and kill the larva.
- Reference:
- 1. Northern Territory Insects, A Comprehensive Guide CD - Graham Brown, 2009.
- 2. What wasp is that? - An interactive identification guide to the Australasian families of Hymenoptera, 2007.
- 3. Pergidae of the World - An online catalogue of the sawfly family Pergidae (Symphyta), Zoologische Staatssammlung München, 2009.
- 4. Insects of Australia, CSIRO, Division of Entomology, Melbourne University Press, 2nd Edition 1991, pp 931.
- 5. Family PERGIDAE - Australian Faunal Directory, Australian Biological Resources Study.
- 6. Saw Flies Order: HYMENOPTERA, suborder: SYMPHYTA - Australian Caterpillars, Don Herbison-Evans & Stella Crossley, 2010.
