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This article is about the hymenopteran. For the moth, see Symphyta (moth genus).
Temporal range: Triassic – Recent
Large rose sawfly (Arge pagana stephensii).jpg
Large rose sawfly
Arge pagana stephensii
Scientific classification e
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Suborder: Symphyta
Gerstäcker 1867[1]

Sawflies are insects belonging to suborder Symphyta of the order Hymenoptera. Sawflies are distinguishable from most other hymenopterans 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.


Bristly rose sawfly Cladius difformis, above millimeter scale


Adult sawflies, except for those in the family Cephidae, have structures that latch onto the underside of the fore wings 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. Adults also have stronger antennae. Among the largest sawfly ever discovered was Hoplitolyda duolunica from the Mesozoic, with a body length of 55 millimetres (2.2 in) and a wingspan of 92 millimetres (3.6 in).[3]


Group of sawfly larvae feeding on leaves

Some larvae look like caterpillars (the larvae of moths and butterflies), with some notable differences; (1) they have six or more pairs of prolegs (sometimes greatly reduced and difficult to see) on the abdomen, while caterpillars have five pairs or fewer, (2) they have two stemmata instead of a caterpillar's six, (3) caterpillars (except for a tiny minority) always have the two first abdominal segments legless, and (4) sawfly larvae have an invariably smooth head capsule with no cleavage lines, while lepidopterous caterpillars bear an inverted "Y" or "V" (adfrontal suture). 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. When harassed, many sawfly larvae are able to squirt a foul liquid from their last segment.


In his original description of Hymenoptera in 1863, Gerstäcker divided them into three groups, Hymenoptera aculeata, Hymenoptera apocrita and Hymenoptera phytophaga.[4] But four years later in 1867, described just two groups, H. apocrita syn. genuina and H. symphyta syn. phytophaga.[1] Consequently the name Symphyta is given to Gerstaecker as the zoological authority. In his description Gerstäcker distinguished the two groups according to the transfer of the first abdominal segment to the thorax in the Apocrita, compared to the Symphyta. Consequently there are only 8 dorsal half segments in Apocrita and 9 in Symphyta. The larvae are distinguished in a similar way.[5]

The Symphyta have therefore traditionally been considered, with Apocrita, to form one of two suborders of Hymenoptera.[6][7] Symphyta are considered the more primitive group,[8] that morphologically have comparatively complete venation, have larvae that are largely phytophagous insects, and lack a "wasp-waist". Together, the Symphyta make up les than 10% of hymenopteran species.[8] While the terms sawfly and Symphyta have been used synonymously, the Symphyta have also been considered in three groups, true sawflies (phyllophaga), woodwasps or xylophaga (Siricidae), and Orussidae. The three groupings have been distinguished by the sawfly's ventral serrated or saw-like ovipositor for sawing holes in vegetation to deposit eggs, while the woodwasp ovipositor penetrates wood and the Orussidae behave as external parasitoids of wood-boring Coleoptera. The woodwasps themselves are a non-monophyletic ancestral grade. Despite these limitations, the terms have utility and are common in the literature[7]

While most hymenopteran superfamilies have been considered to be monophyletic as is Hymenoptera, the grouping of these as Symphyta has long been realised as paraphyletic.[9][10] Increasing use of cladistic methods, first used in 1969,[11] and molecular phylogenetics is improving the understanding of inter-superfamily relationships, resulting in revisions at the level of superfamily and family. Although higher-level phylogenetic relationships are still not completely resolved the Symphyta are regarded as the most primitive (basal) taxa within the Hymenoptera[10][8] (some going back 200 million years), and one of the taxa within the Symphyta subsequently gave rise to the suborder Apocrita (wasps, bees, and ants), which is considered monophyletic. In cladistic analyses the Orussoidea are consistently shown to be the sister group to the Apocrita.[7][8]

Fossils in the family Xyelidae are regarded as the oldest of all insects known in Hymenoptera, dating back to the Lower Triassic from rocks collected in the Soviet Union.[12]


There are approximately 8,000 species of sawflies,[13] although new species continue to be discovered.[14] Early phylogenies, based on morphology and behaviour, such as that of Alexandr Rasnitsyn[15] identified nine clades though these did not reflect historical division into superfamilies and families. Such classifications were replaced by those using molecular methods, following the work of Dowton and Austin (1994).[16]

As of 2013 these are treated as nine superfamilies (one extinct) and 25 families, but most belong to the Tenthredinoidea superfamily, with about 7,000 species worldwide. Tenthredinoidea has six families, of which Tenthredinidae is the largest.[6][2]

Superfamilies and families
  • Superfamily Anaxyeloidea Martynov, 1925
  • Superfamily Cephoidea Newman, 1834 (1 & †1family)
    • Family Cephidae Newman, 1834 (21 genera, 160 spp.[b]) & †3 genera
  • †Superfamily Karatavitoidea Rasnitsyn, 1963 (1 family)
  • Superfamily Orussoidea Newman, 1834 (1 & †1 family)
    • Family Orussidae Newman, 1834 (16 genera, 82 spp.) & †3 genera
  • Superfamily Pamphilioidea Cameron, 1890 (2 & †1 families) (syn. Megalodontoidea)
    • Family Megalodontesidae Konow, 1897 (1 genera, 42 spp.) & †1 genus
    • Family Pamphiliidae Cameron, 1890 (10 genera, 291 spp.) & †3 genera
  • Superfamily Siricoidea Billberg, 1820 (2 & †5 families)
    • Family Siricidae Billberg, 1820 (11 genera, 111 spp.) & †9 genera
  • Superfamily Tenthredinoidea Latreille, 1803 (6 & †2 families)
    • Family Argidae Konow, 1890 (58 genera, 897 spp.) and †1 genus
    • Family Blasticotomidae Thomson, 1871 (2 genera, 12 spp.) & †1 genus
    • Family Cimbicidae W. Kirby, 1837 (16 genera, 182 spp.) & †6 genera
    • Family Diprionidae Rohwer, 1910 (11 genera, 136 spp.) & †2 genera
    • Family Pergidae Rohwer, 1911 (60 genera, 442 spp.)
    • Family Tenthredinidae Latreille, 1803 (400 genera, 5,500 spp.) & †14 genera
  • Superfamily Xiphydrioidea Leach, 1819
  • Superfamily Xyeloidea Newman, 1834
    • Family Xyelidae Newman, 1834 (5 genera, 63 spp.) & †47genera

Diversity (Superfamilies)
(Syntexis libocedrii
(Cephus sp.)
(Orussus coronatus
(Pamphilius sp.)
(Sirex noctilio
(Tenthredo notha)
(Xiphydria camelus)
(Xyela julii)


Sawflies are widely distributed throughout the world, but their range continues to expand.[17]


Sawfly ovipositing

Sawflies are herbivores, feeding on plants that have a high concentration of chemical defences. These insects are either resistant to the chemical substances, or they avoid areas of the plant that have high concentrations of chemicals.[18] The larvae primarily feed in groups; they are folivores, consuming plants and fruits on native trees and shrubs, though some are parasitic.[19][20][21] However, this is not always the case; Monterey pine sawfly (Itycorsia) larvae are solitary web-spinners that feed on Monterey pine trees inside a silken web.[22] The adults feed on pollen and nectar.[19]

Schematic preview of the sawflies found in the regions of Pijanec and Maleš in Macedonia (legends in Macedonian and English)

Sawflies are eaten by a wide variety of predators. Both adults and larvae, along with other insects, are an essential food source for stonechat (Saxicola) birds.[23] The larvae are also important for partridge chicks.[24] Based on a study, the diet of nestling corn buntings (Emberiza calandra), the larvae of sawflies and moths compromised one third of their diet, although sawfly larvae would be eaten more frequently on cool days in comparison in warm temperatures. The larvae are not regarded as important to the diet of corn buntings.[25] Black grouse (Tetrao tetrix) chicks show a preference for sawfly larvae which makes them one of the most consumed invertebrates by them.[26][27] Even if there are high populations of other insects, the chicks still predominately feed on the larvae. Sawfly larvae comprised 43% of the diet of chestnut-backed chickadees (Poecile rufescens).[22] Small mammals prey on sawfly cocoons, causing high mortality rates among them. These predators include the masked shrew (Sorex cinereus), the northern short-tailed shrew (Blarina brevicauda) and the deer mouse (Peromyscus maniculatus).[28] Insects such as ants and certain species of predatory wasps (Vespula vulgaris) eat sawflies.[29][30]

Spitfire sawfly larvae in a group together on a tree: Larvae that group together are less likely to die from predators.

The larvae have several defensive tactics against predators. While adults are unable to sting, the larvae regurgitate a liquid from their mouths which is distasteful and irritating to potential predators, which makes them avoid the larvae.[20] The larvae also cluster together which reduces their chances of getting killed, and in some cases, a group of larvae will form together with their heads pointing outwards or tap their abdomens up and down.[31]


Sawflies are hosts to many parasitoids, most of which are parasitic Hymenoptera; more than 40 species known to attack them. However, fewer than 10 of these species actually cause a significant impact on sawfly populations.[32]

See also[edit]


  1. ^ a b †: extinct
  2. ^ spp.: species


  1. ^ a b Gerstaecker 1867.
  2. ^ a b Aguiar et al 2013.
  3. ^ Gao, Taiping; Shih, Chungkun; Rasnitsyn, Alexandr P.; Ren, Dong; Laudet, Vincent (2013). "Hoplitolyda duolunica gen. et sp. nov. (Insecta, Hymenoptera, Praesiricidae), the Hitherto Largest Sawfly from the Mesozoic of China". PLoS ONE. 8 (5): e62420. Bibcode:2013PLoSO...862420G. doi:10.1371/journal.pone.0062420. PMC 3643952free to read. PMID 23671596. 
  4. ^ Carus & Gerstaecker 1863, Hymenoptera p. 189
  5. ^ Dallas 1867, Hymenoptera p. 307
  6. ^ a b Goulet & Huber 1993.
  7. ^ a b c Sharkey 2007.
  8. ^ a b c d Mao et al 2015.
  9. ^ Sharkey et al 2016.
  10. ^ a b Song et al 2016.
  11. ^ Hennig 1969.
  12. ^ Hermann, Henry R. (1979). Social Insects. 1. Oxford: Elsevier Science. p. 85. ISBN 978-0-323-14979-2. 
  13. ^ Asaro 2008.
  14. ^ Skvarla et al 2016.
  15. ^ Rasnitsyn 1988.
  16. ^ Dowton & Austin 1994.
  17. ^ Looney et al 2016.
  18. ^ Rosenthal, Gerald A.; Berenbaum, May R. (1991). Herbivores Their Interactions with Secondary Plant Metabolites. (2nd ed.). Oxford: Elsevier Science. p. 190. ISBN 978-0-323-13940-3. 
  19. ^ a b "Sawflies (Tenthredinoidae)". BBC. Retrieved 11 August 2015. 
  20. ^ a b Australian Museum (20 October 2009). "Animal Species:Sawflies". Retrieved 11 August 2015. 
  21. ^ Bandeili, Babak; Müller, Caroline (2009). "Folivory versus florivory—adaptiveness of flower feeding". Naturwissenschaften. 97 (1): 79–88. Bibcode:2010NW.....97...79B. doi:10.1007/s00114-009-0615-9. PMID 19826770. 
  22. ^ a b Kleintjes, P. K.; Dahlsten, D. L. (1994). "Foraging Behavior and Nestling Diet of Chestnut-Backed Chickadees in Monterey Pine" (PDF). The Condor. 96 (3): 647–653. doi:10.2307/1369468. JSTOR 1369468. 
  23. ^ Cummins, S.; O'Halloran, J. (2002). "An assessment of the diet of nestling Stonechats using compositional analysis: Coleoptera (beetles), Hymenoptera (sawflies, ichneumon flies, bees, wasps and ants), terrestrial larvae (moth, sawfly and beetle) and Arachnida (spiders and harvestmen) accounted for 81% of Stonechat nestling diet.". Bird Study. 49 (2): 139–145. doi:10.1080/00063650209461258. 
  24. ^ Campbell, L.H.; Avery, M.I.; Donald, P.; Evans, A.D.; Green, R.E.; Wilson, J.D. (1997). A Review of the Indirect Effects of Pesticides on Birds (PDF) (Report). Peterborough, UK: Joint Nature Conservation Committee, Report. no 227. p. 27. ISSN 0963-8091. 
  25. ^ Brickle, N. W.; Harper, D. G. C. (1999). "Diet of nestling Corn Buntings Miliaria calandra in southern England examined by compositional analysis of faeces". Bird Study. 46 (3): 319–329. doi:10.1080/00063659909461145. 
  26. ^ Starling-Westerberg, A. (2001). "The habitat use and diet of Black Grouse Tetrao tetrix in the Pennine hills of northern England". Bird Study. 48 (1): 76–89. doi:10.1080/00063650109461205. 
  27. ^ Cayford, J.T. (1990). "Distribution and habitat preferences of Black Grouse in commercial forests in Wales: conservation and management implications". Proceedings of the International Union Game of Biologists Congress. 19: 435–447. 
  28. ^ Holling, C. S. (1959). "The Components of Predation as Revealed by a Study of Small-Mammal Predation of the European Pine Sawfly" (PDF). The Canadian Entomologist. 91 (5): 293–320. doi:10.4039/Ent91293-5. 
  29. ^ Müller, Caroline; Brakefield, Paul M. (2003). "Analysis of a Chemical Defense in Sawfly Larvae: Easy Bleeding Targets Predatory Wasps in Late Summer". Journal of Chemical Ecology. 29 (12): 2683–2694. doi:10.1023/B:JOEC.0000008012.73092.01. ISSN 1573-1561. PMID 14969355. 
  30. ^ Petre, Charles-Albert; Detrain, Claire; Boevé, Jean-Luc (2007). "Anti-predator defence mechanisms in sawfly larvae of Arge (Hymenoptera, Argidae)". Journal of Insect Physiology. 53 (7): 668–675. doi:10.1016/j.jinsphys.2007.04.007. PMID 17540402. 
  31. ^ Phillips, Charlma (December 1992). "Spitfires – Defoliating Sawflies" (PDF). Department of Primary Industries and Resources. Government of South Australia. Retrieved 11 August 2015. 
  32. ^ Capinera 2008, p. 1827.


Books and chapters[edit]


Catalogue of Symphyta[edit]

External links[edit]