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The spitfire sawfly (Perga affinis) is a species of hymenopteran insect in the family Pergidae. It is found in Australia and grows to 22 mm (0.87 in) in length with two pairs of honey-colored wings up to 40 mm (1.6 in) in wingspan. Its larvae are up to 80 mm (3.1 in) long and somewhat resemble a typical caterpillar.
| Spitfire sawfly | |
|---|---|
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Suborder: | Symphyta |
| Family: | Pergidae |
| Genus: | Perga |
| Species: | P. affinis
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| Binomial name | |
| Perga affinis Kirby, 1882
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The sawfly derives its name from the saw-like ovipositor of the female,[1] which is used to open holes in the plant within which she lays her eggs. While closely related to wasps, sawflies lack both the narrow waists and stings of wasps.
Although the adults of this sawfly species are not often seen, the larvae are quite conspicuous as they grow larger, resembling caterpillars.[2] Steelblue sawfly larvae are usually seen during the day in groups on the branches and stems of Eucalyptus trees. At night, they disperse to eat leaves of the host plants. When threatened, the larvae raise their heads and eject a strong-smelling, yellow-green liquid consisting predominantly of eucalyptus oil, to deter predators.[1] This action gives them their common name of spitfires.
Description
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The larvae vary from dark blue or black to yellow and brown, and are up to 80 mm (3.1 in) long. The body is sparsely covered with short white bristles. During the day, the larvae congregate in clusters of 20 to 30 for protection and disperse at night to feed. The adults are mainly black or brown, with yellowish markings and are about 25 mm (0.98 in) long.
Life cycle
editThe adults are found from about January to May, though mainly in autumn. Eggs are laid under leaf surfaces with the saw-like ovipositor. The larvae are mainly active during late winter and spring and enter the soil to pupate usually in mid-spring. Pupation takes place in strong, paper-like cocoons, which are often clustered several centimetres deep in the soil. The pupal stage may extend over two or three years before the adult emerges.[3]
Damage
editLarvae of spitfires feed on the foliage of young trees and regrowth stems, and can strip the branches of foliage, particularly at the tops. This is usually replaced during the spring-summer flush of leaf growth. Serious retardation of high growth may result from repeated attack, but host death is unusual.[1] Wandoo is the most commonly attacked species in Western Australia.
Control
editThis defoliator rarely causes widespread damage, but where the clusters of larvae are accessible, the simplest method of control is to remove and destroy them during the day. Several parasitic wasps also have some controlling effect.[1][3]
References
edit- ^ a b c d Charlma Phillips (December 1992). "Spitfires - Defoliating Sawflies". PIRSA. Archived from the original on 6 November 2009. Retrieved 2010-04-10.
- ^ Gary, Opit (17 January 2008). "Sawflies and spitfire grubs". abc.net.au. Retrieved 10 April 2010.
- ^ a b Nikki Galovic; Juanita Rodriguez (16 November 2018). "Great balls of spitfires". CSIRO.
External links
edit- Sawflies: a close relative of wasps Retrieved 2010-04-10. CSIRO.
- Thoughts on the evolution of insects 'from sawfly to ant' Retrieved 26-10-2010 Brisbane Insects
- Sawflies Australian Museum