Pterygophorinae larva identification & breeding biology
Workbook
This page deals with the breeding biology of Pterygophorinae sawflies and species identification of their larvae.
It draws on information in the published literature and iNaturalist observations.
There are two genera in the subfamily Pterygophorinae - Lophyrotoma and Pterygophorus. See this workbook page for identification of adults.
Notes from Macdonald & Ohmart (1993)
“As in the Perginae, female Pterygophorinae emerge from pupation with mature egg complements and proceed to search for suitable oviposition sites. Females have not been observed to engage in the preoviposition behavior of cuticle removal on leaves as rows of eggs are laid into the leaf margin rather than the leaf midrib. Females are short-lived despite the fact they have been observed feeding on nectar and are often collected on flowers.
Larvae hatch some weeks after oviposition, and the newly emerged larvae aggregate at the tip of the leaf. Feeding involves skeletonizing the leaf, and "row-type" feeding behavior has been observed. In species of Pterygophorous, larvae continue this type of feeding behavior until the third instar, when aggregations disperse and larvae feed singly. However, larvae of some Lophyrotoma species maintain their larval aggregations and continue the row-type feeding behavior throughout the remaining larval instars.
Pterygophorine larvae appear to pass through six instars, as in the Perginae, although this matter is confused by the fact that in the Pterygophorinae the last larval ecdysis (i.e., molt to the prepupal stage) occurs while the larvae are on the foliage of the host plant. The nonfeeding prepupal stage then proceeds to find a suitable pupation site. The prepupal stage is quite different in appearance to the larva and is a nonfeeding stage.
The pupation site for the two genera in the Pterygophorinae have been found to differ. Species of Pterygophorus have been observed to pupate within timber or bark, in some cases, the bark of the host plant. The prepupae form a cell within the timber or bark. The entrance hole is sealed by the formation of a septum (sometimes two), and the cell is lined with a resinlike material but is lacking silk. Species in the genus Lophyrotoma, on the other hand, leave the host plant and enter the soil, where they form a simple cocoon of soil particles and silk, which lacks internal compartmentalization.
The prepupal stage in the Pterygophorinae, like the prepupal stage in the Perginae, involves a pause in development and serves to provide the over-wintering life stage for most species. However, some species are multivoltine, and pupation may be completed in a little over a week.
Genus Lophyrotoma
Lophyrotoma analis
Morphology and colour of larva:
Notes from Schmidt et al. (2006):
“The larvae are morphologically similar to the larvae of the family Argidae. The body is laterally broadened ventrally and lacks any apical or dorsal appendages (Fig. 8).
The head is orange-brown and the body has a whitish appearance and the internal organs and gut contents shine through the translucent cuticle, giving the larva a slightly greenish colour. Only the first thoracic segment dorsally apex differ in colour, being more or less yellow. The entire body is covered with black spots (Fig. 8)”
Breeding biology:
Notes from Schmidt (2006) and Schmidt et al (2006):
Food plants for L. analis: Emex australis, Muehlenbeckia sp., Rumex sp.
"Lophyrotoma analis is polyvoltine in the Brisbane area and in suitable habitats larvae can be found almost all year except for a short period in winter. After completing their development the larvae enter the soil and prepare a cocoon where they develop to the adult stage within 13–22 days. Males lived for 6 to 10 days and females 3 to 9 days with access to water and honey.
Females place their eggs into the leaf margin of their host plant. The eggs are laid singly, not in clusters as in species of the subfamily Perginae, although a leaf may receive several eggs. (Note: L. analis appears to be exceptional in this regard. All other Lophyrotoma spp appear to lay eggs in clusters. This difference in behaviour may be due to the wavy leaf margin of the host plant Emex or Rumex compared to the regular margin of eucalypt and Melaleuca, the host plants for other Lophyrotoma spp).
When a female is placed on a dock leaf it almost invariably starts immediately to examine the surface with its ovipositor tip, by bending the abdomen. It then uses the antennae to examine the leaf surface and moves to the leaf margin where it usually starts ovipositing at once (Fig. 7 above)”.
iNaturalist observations:
iNat observation from remco showing Lophyrotoma analis ovipositing along leaf edge
iNat observation by coddiwompler shows Lophyrotoma analis ovipositing along the leaf margin. The following annotated image sequence is extracted from her movie on FaceBook.
Lophyrotoma cygna
Larva morphology and colour
Following panel of photos from iNaturalist observation by kirrrkus in Margaret River area, WA. Larva feeding on Melaleuca thymoides.
This is a good candidate for L. cygna based on fact that the only other Pterygophorinae species in WA are L. zonalis and L. analis, which can be excluded based on location, morphology and host plant.
Lophyrotoma interrupta
Larva morphology and breeding biology:
Schmidt (2006) lists the following food plants for L. interrupta: Angophora floribunda, Corymbia gummifera, C. maculata, Eucalyptus camaldulensis, E. crebra, E. grandis, E. intermedia, E. melanophloia, E. moluccana, E. nicholii, E. obliqua, E. ovata, E. populnea, E. siderophloia, E. viminalis, Leptospermum sp.
iNaturalist observation by natashataylor - Brisbane, showing L. interrupta inserting saw into Eucalyptus leaf to separate cuticle from epidermis creating a space to insert an egg to an existing row.
Lophyrotoma leachii
Breeding biology
These iNaturalist observations show L. leachii ovipositing on the margin of eucalypt leaves. The eggs are laid in a cluster.
Lophyrotoma zonalis
Larva morphology and colour:
Images from iNaturalist observations and BOLD:
Breeding biology:
Schmidt (2006) states that the food plants of L. zonalis are Melaleuca dealbata, M. leucadendra, M. quinquenervia and M. viridiflora.
iNaturalist observation by francytee of L. zonalis ovipositing into edge of Melaleuca leaf. Extended saw pushed into leaf is visible in all photos. Eggs are laid in a cluster.
Burrows & Balciunas (1997) state that “P. zonalis embryonic period is 3-4 weeks (but may be longer in winter) and larval development through perhaps 10 instars takes 5 weeks.
The larvae burrow into the thick, papery bark of Melaleuca spp. and form holes in the outer bark layers. Pupation takes 20-23 days (range 17-52 days).
Adults emerging from a given batch may be all males or all females or a mix. Reproduction is parthenogenetic and females may begin ovipositing within 2 days of becoming adults.
The female inserts her ovipositor into leaf tissue in a line along the leaf margin, laying 20-30 eggs. Females can lay up to 6 batches of eggs.
Emergence from eggs is highly synchronised and the larvae begin feeding at the tip of the leaf in a feeding front. After consuming that leaf they move to another and reform a front. After several moults they disperse and feed individually. The female does not feed and dies within 4-6 days”.
Genus Pterygophorus
Pterygophorus cinctus
Larva morphology and colour
brooks70 has successfully captive-reared P. cinctus larvae (shown below) through to adults - see iNat observation. Larvae were fed on cut foliage from their host tree - a Melaleuca cultivar.
Larvae pupated in a Allocasuarina log over a 35 day period. Pupation took place largely at night.
Females, one of which is shown in this image, eclosed between 47 and 52 days later.
Detailed description of the adult female, which matches descriptions in the literature of P. cinctus, in this Notes page.
Breeding biology
Information from iNaturalist observations
The following images from this iNat observation by jenncxoxo show a female P. cinctus laying eggs into the margin of a Callistemon leaf. Eggs are laid in clusters, not individually.
Clutches of eggs on Callistemon leaves are shown below. One clutch in the left photo has hatched. The other two photos show that the embryos become coloured as they develop, taking on the colour of the larva.
The adult female of P. cinctus, like other Pterygophorinae, apparently uses the sawsheath just as a brace to steady the abdomen while straddling the narrow leaf margin. It does not perform the role of the pergid sawsheath, which removes the waxy layer on the epidermis of the leaf prior to oviposition. As a result, it lacks the serrations found in pergids as well as the hairs which sweep away abraded material - see photos below from this Notes page.
Pterygophorus insignis
Image from BOLD of larva
Breeding biology:
Schmidt (2006) lists the food plants of P. insignis as Callistemon sp., Leptospermum sp. and Melaleuca armillaris.
Purcell & Goolsby (2005) report following pupal periods at these locations: Chelmer (Brisbane) 66 days; Coolum (Sunshine Coast) 13-17 days, 86 days, 69 days; Fitzgibbon (Brisbane) 16-40 days, 80-81 days; Burpengary (Brisbane) 51 days; Poona NP (Maryborough) 68 days.
Pterygophorus turneri
Breeding biology:
Schmidt (2006) lists the food plant of P. turneri as Syzygium francisii.
Morphology and colour of larva
Larvae shown below from iNaturalist observations show a distinctive black dorsal projection from the prothoracic segment and a green body colour with yellow longitudinal stripes.
Host plants for Pterygophorinae larvae - from Schmidt. (2006)
Lophyrotoma
L. analis - Emex australis, Muehlenbeckia sp., Rumex sp.
L. cyanea - Eucalyptus radiata
L. interrupta - Angophora floribunda, Corymbia gummifera, C. maculata, E. camaldulensis, E. crebra, E. grandis, E. intermedia, E. melanophloia, E. moluccana, E. nicholii, E. obliqua, E. ovata, E. populnea, E. siderophloia, E. viminalis, Leptospermum sp.
L. leachii - creeper in rainforest
L. zonalis - Melaleuca dealbata, M. leucadendra, M. quinquenervia, M. viridiflora
Pterygophorus
P. cinctus - Leptospermum sp.
P. insignis - Callistemon sp., Leptospermum sp., Melaleuca armillaris
P. turneri - Syzygium francisii
References:
Benson, R.B. (1938) A revision of the genus Pterygophorus Klug, sensu lato, with the description of two new genera (Hymenoptera, Symphyta) Annals and Magazine of Natural History 1: 610-625.
Burrows, D.W. & Balciunas, J.K. (1997) Biology, distribution and host-range of the sawfly, Lophyrotoma zonalis (Hym., Pergidae), a potential biological control agent for the paperbark tree, Melaleuca quinquenervia. Entomophaga 42: 299-313.
Macdonald, J.A. & Ohmart, C.P. (1993) Life history strategies of Australian pergid sawflies and their interactions with host plants. in “Sawfly life history adaptations to woody plants.” Wagner, M.R. & Raffa, K.F. (eds). Academic Press.
Malagon-Aldana, L.A. et al (2021) Comparative anatomy of the larvae of argid sawflies (Hymenoptera:Argidae): a phylogenetic approach. Organisms Diversity & Evolution 21: 361-392.
Purcell, M. and Goolsby, J.A. 2005. Herbivorous insects associated with the paperbark Melaleuca quinquenervia and its allies: VI. Pergidae. Australian Entomologist 32: 37-48.
Schmidt, S. (2006) Checklist of the Pergidae (Hymenoptera: Symphyta) of Australasia In Blank, S., Schmidt, S. & Taeger, A. (eds), Recent Sawfly Research: Synthesis and Prospects. Goecke & Evers, Keltern, pp. 627-634.
Schmidt, S., Walter, G.H., Grigg, J. & Moore, C.J. (2006). Sexual Communication and Host Plant Associations of Australian Pergid Sawflies (Hymenoptera, Symphyta, Pergidae). In Blank, S., Schmidt, S. & Taeger, A. (eds), Recent Sawfly Research: Synthesis and Prospects. Goecke & Evers, Keltern.
Takeuchi, M. & Zalucki, M.P. (2022) Feeding behaviour in Australian gregarious Lophyrotoma sawflies (Hymenoptera: Pergidae). Austral Entomology 61: 494-504
This is a workbook page … a part of our website where we record the observations and references used in making species identifications. The notes will not necessarily be complete. They are a record for our own use, but we are happy to share this information with others.