A larva ( / ˈ l ɑːr v ə / ; pl. : larvae / ˈ l ɑːr v iː / ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects , some arachnids , amphibians , or cnidarians typically have a larval phase of their life cycle .
77-529: See text The Xyelidae are a comparatively species-poor family of sawflies , comprising about 80 extant species in five genera worldwide, and is the only family in the superfamily Xyeloidea . The fossil record of the family is extensive, comprising more than 120 species and including the oldest fossil Hymenoptera species dating back to the Triassic , between 245 and 208 million years ago. Xyelidae are to be regarded as living fossils since they represent one of
154-428: A dagger ( † ). Many species of sawfly have retained their ancestral attributes throughout time, specifically their plant-eating habits, wing veins and the unmodified abdomen, where the first two segments appear like the succeeding segments. The absence of the narrow wasp waist distinguishes sawflies from other members of hymenoptera, although some are Batesian mimics with coloration similar to wasps and bees, and
231-502: A relict group. The Electronic World Catalog of Symphyta provides a complete account of the valid extant genera and species, their synonyms, the concerning references to original descriptions and distribution data on the level of countries and provinces. The European species can be identified with help of „The Western Palaearctic Xyelidae“ of Blank (2002), all Eurasian species of Xyela with Blank et al. (2013). The North American Macroxyelinae were revised by Smith & Schiff (1998),
308-537: A conspicuous pattern of black spots (see plate 21 figure 3 in) or they resemble bird droppings. The roundish head capsule bears a larval eye ( stemma ) on each side, which is reduced in mining species, and short antennae comprising five articles. The thorax bears short legs comprising three articles. Unlike the larvae of all other Hymenoptera and Lepidoptera which lack prolegs on at least the first abdominal segment, larvae of Xyelidae have prolegs on all abdominal segments. In free feeding Xyelidae ( Macroxyela , Megaxyela )
385-402: A family or genus of hosts. For example, Iris sawfly larvae, emerging in summer, can quickly defoliate species of Iris including the yellow flag and other freshwater species. Similarly the rose sawflies, Arge pagana and A. ochropus , defoliate rose bushes. The giant woodwasp or horntail, Urocerus gigas , has a long ovipositor, which with its black and yellow colouration make it
462-465: A good mimic of a hornet . Despite the alarming appearance, the insect cannot sting. The eggs are laid in the wood of conifers such as Douglas fir , pine, spruce , and larch . The larvae eat tunnels in the wood, causing economic damage. Alternative measures to control sawflies can be taken. Small-scale, mechanical methods include visually confirming larval presence on a plant and subsequently removing them, either by pruning damaged leaves or removing
539-835: A humid and warm climate. The cladogram is based on Schulmeister 2003. Xyeloidea ( Triassic –present) [REDACTED] Tenthredinoidea [REDACTED] Pamphilioidea [REDACTED] Cephoidea (stem sawflies) [REDACTED] Siricoidea (horntails or wood wasps) [REDACTED] Xiphydrioidea (wood wasps) [REDACTED] Orussoidea ( parasitic wood wasps) [REDACTED] Apocrita ( ants , bees , wasps ) [REDACTED] There are approximately 8,000 species of sawfly in more than 800 genera, although new species continue to be discovered. However, earlier studies indicated that 10,000 species grouped into about 1,000 genera were known. Early phylogenies such as that of Alexandr Rasnitsyn , based on morphology and behaviour, identified nine clades which did not reflect
616-416: A leaf. Larvae that feed on wood will pupate in the tunnels they have constructed. In one species, the jumping-disc sawfly ( Phyllotoma aceris ) forms a cocoon which can act like a parachute. The larvae live in sycamore trees and do not damage the upper or lower cuticles of leaves that they feed on. When fully developed, they cut small perforations in the upper cuticle to form a circle. After this, they weave
693-424: A long basal segment followed by a series of tiny segments, as in the tibia-tarsus . Xyelidae are small Hymenoptera. Most species are 3 to 5 mm long, but species of Macroxyela and Megaxyela of East Asia and North America are larger, measuring 10 to 15 mm. The imagines display a number of ancestral characters of Hymenoptera, which may be absent in more derived lineages of Hymenoptera. Those include
770-483: A newly growing leaf to provide shelter for their eggs which are fixed with glutinous material between on the upper sides of the folded leaf. Many species of Xyelidae facultatively diapause for several years. In Xyela alpigena and Xyela obscura a diapause of at least two years is obligate. This strategy might have evolved to ensure well developed cones are available for oviposition: the host plants Pinus cembra and Pinus mugo produce cones very irregularly in
847-412: A number of chemicals, including maldison , dimethoate , carbaryl , imidacloprid , etc., if removing larvae from trees is not effective enough. Larva A larva's appearance is generally very different from the adult form ( e.g. caterpillars and butterflies ) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. In
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#1732852563002924-569: A silk hammocks within the circle; this silk hammock never touches the lower cuticle. Once inside, the upper-cuticle's disc separates and descends towards the surface with the larvae attaching themselves to the hammock. Once they reach the round, the larvae work their way into a sheltered area by jerking their discs along. The majority of sawfly species produce a single generation per year, but others may only have one generation every two years. Most sawflies are also female, making males rare. Sawflies are major economic pests of forestry . Species in
1001-436: A wingspan of 92 mm ( 3 + 1 ⁄ 2 in). The smaller species only reach lengths of 2.5 mm ( 3 ⁄ 32 in). Heads of sawflies vary in size, shape and sturdiness, as well as the positions of the eyes and antennae. They are characterised in four head types: open head, maxapontal head, closed head and genapontal head. The open head is simplistic, whereas all the other heads are derived. The head
1078-509: Is Hymenoptera, the Symphyta has long been seen to be paraphyletic. Cladistic methods and molecular phylogenetics are improving the understanding of relationships between the superfamilies, resulting in revisions at the level of superfamily and family. The Symphyta are the most primitive ( basal ) taxa within the Hymenoptera (some going back 250 million years), and one of the taxa within
1155-589: Is a warning colouration because some larvae can secrete irritating fluids from glands located on their undersides. Sawflies are widely distributed throughout the world. The largest family, the Tenthredinidae, with some 5,000 species, are found on all continents except Antarctica, though they are most abundant and diverse in the temperate regions of the northern hemisphere; they are absent from New Zealand and there are few of them in Australia. The next largest family,
1232-460: Is also hypognathous, meaning that the lower mouthparts are directed downwards. When in use, the mouthparts may be directed forwards, but this is only caused when the sawfly swings its entire head forward in a pendulum motion. Unlike most primitive insects, the sutures (rigid joints between two or more hard elements on an organism) and sclerites (hardened body parts) are obsolescent or absent. The clypeus (a sclerite that makes up an insects "face")
1309-588: Is between 205.6 and 221.5 million years of age, making it among the oldest of all sawfly fossils. More Xyelid fossils have been discovered from the Middle Jurassic and the Cretaceous , but the family was less diverse then than during the Mesozoic and Tertiary . The subfamily Xyelinae were plentiful during these time periods, in which Tertiary faunas were dominated by the tribe Xyelini; these are indicative of
1386-432: Is minimal, and fewer than 10 of these species actually cause a significant impact on sawfly populations. Many of these species attack their hosts in the grass or in other parasitoids. Well known and important parasitoids include Braconidae , Eulophidae and Ichneumonidae . Braconid wasps attack sawflies in many regions throughout the world, in which they are ectoparasitoids, meaning that the larvae live and feed outside of
1463-679: Is most frequent in the anal veins. In all sawflies, 2A and 3A tend to fuse with the first anal vein. This occurs in several families including Argidae, Diprionidae and Cimbicidae. The larvae of sawflies are easily mistaken for lepidopteran larvae (caterpillars). However, several morphological differences can distinguish the two: while both larvae share three pairs of thoracic legs and an apical pair of abdominal prolegs , lepidopteran caterpillars have four pairs of prolegs on abdominal segments 3–6 while sawfly larvae have five pairs of prolegs located on abdominal segments 2–6; crochets are present on lepidopteran larvae, whereas on sawfly larvae they are not;
1540-434: Is not always the case; Monterey pine sawfly ( Itycorsia ) larvae are solitary web-spinners that feed on Monterey pine trees inside a silken web. The adults feed on pollen and nectar. Sawflies are eaten by a wide variety of predators. While many birds find the larvae distasteful, some such as the currawong ( Strepera ) and stonechats ( Saxicola ) eat both adults and larvae. The larvae are an important food source for
1617-517: Is not divided into a pre- and postclypeus, but rather separated from the front. The antennal sclerites are fused with the surrounding head capsule, but these are sometimes separated by a suture. The number of segments in the antennae vary from six in the Accorduleceridae to 30 or more in the Pamphiliidae. The compound eyes are large with a number of facets, and there are three ocelli between
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#17328525630021694-487: Is still enclosed by the pupal skin. At this stage, the wings are not expanded, and in females, the ovipositor and its sheath curve dorsally above the tip of the abdomen. The decticous pupae are capable of biting open the cocoon, digging to the surface of the ground, moving around on the surface, and drinking (figs 22-23 in). This pupal form is an ancestral character of holometabolan insects . In other orders, it occurs in including Neuropterida , Mecoptera , Trichoptera and in
1771-1041: Is supposed. Many species of Xyelidae are host specific, with only a single larval host plant known. Monophagy is the prevailing life style in most species of Xyela . For this genus, the date of oviposition is closely correlated with the development of the staminate cones of the host pines, which might prevent a host shift in many cases. For some North American species of Xyela the association with each several species of pines ( oligophagy ) has been reported in literature, but supposedly such records are often based on taxonomic problems to separate morphologically similar species of Xyela properly. Through molecular access, true oligophagy could be demonstrated recently for Xyela bakeri (associated at least with Pinus contorta , Pinus ponderosa and Pinus sabiniana ) and Xyela brunneiceps (associated with Pinus flexilis and Pinus strobiformis ). Lack of reliable, reproducible host data could cause inaccurate reports of monophagy or oligophagy in many taxa of Xyelidae, but at least some of
1848-451: Is the product from the ontogenetic fusion of several antennal articles, and it is unique among the extant Hymenoptera species. In Pleroneura , Xyelecia and most species of Xyela the maxillary palps are strongly enlarged and bear specialized setae on the distal articles. The wing venation is the most complete among Hymenoptera: Only in Xyelidae the radial sector Rs furcates into
1925-404: Is two months to two years, though the adult life stage is often very short (approximately 7 – 9 days), only long enough for the females to lay their eggs. The female uses its ovipositor to drill into plant material to lay her eggs (though the family Orussoidea lay their eggs in other insects). Plant-eating sawflies most commonly are associated with leafy material but some specialize on wood, and
2002-779: The Argidae , with some 800 species, is also worldwide, but is most common in the tropics, especially in Africa, where they feed on woody and herbaceous angiosperms . Of the other families, the Blasticotomidae and Megalodontidae are Palearctic ; the Xyelidae, Pamphilidae , Diprionidae , Cimbicidae , and Cephidae are Holarctic , while the Siricidae are mainly Holarctic with some tropical species. The parasitic Orussidae are found worldwide, mostly in tropical and subtropical regions. The wood-boring Xiphydriidae are worldwide, but most species live in
2079-556: The Triassic . The oldest superfamily, the Xyeloidea , has existed into the presents. Over 200 million years ago, a lineage of sawflies evolved a parasitoid lifestyle, with carnivorous larvae that ate the eggs or larvae of other insects. Sawflies are distributed globally, though they are more diverse in the northernmost hemispheres. The suborder name "Symphyta" derives from the Greek word symphyton , meaning 'grown together', referring to
2156-458: The masked shrew ( Sorex cinereus ), the northern short-tailed shrew ( Blarina brevicauda ) and the deer mouse ( Peromyscus maniculatus ) predate heavily on sawfly cocoons. Insects such as ants and certain species of predatory wasps ( Vespula vulgaris ) eat adult sawflies and the larvae, as do lizards and frogs. Pardalotes , honeyeaters and fantails ( Rhipidura ) occasionally consume laid eggs, and several species of beetle larvae prey on
2233-623: The subalpine zone of the European Alps . Adults of Xyela are pollen feeders of a variety of plants, which bear flowers with easily accessible pollen (e.g., Betula , Cercocarpus , Ostrya , Pinus , Purshia , Quercus , Salix ). The enlarged maxillary palps of most Xyela (and supposedly also of Pleroneura and Xyelecia ) serve for the extraction of pollen from the flowers. Although they feed upon often economically important tree species, Xyelidae are usually of only small significance as pest organisms. Pleroneura piceae damages
2310-449: The 1930s and 1950s and C. pygmaeus in the 1930s and 1940s. Like all other hymenopteran insects, sawflies go through a complete metamorphosis with four distinct life stages – egg, larva, pupa and adult. Many species are parthenogenetic , meaning that females do not need fertilization to create viable eggs. Unfertilized eggs develop as male, while fertilized eggs develop into females ( arrhenotoky ). The lifespan of an individual sawfly
2387-612: The Apocrita, to form one of two suborders of Hymenoptera. Symphyta are the more primitive group, with comparatively complete venation , larvae that are largely phytophagous , and without a "wasp-waist", a symplesiomorphic feature. Together, the Symphyta make up less than 10% of hymenopteran species. While the terms sawfly and Symphyta have been used synonymously, the Symphyta have also been divided into three groups, true sawflies (phyllophaga), woodwasps or xylophaga (Siricidae), and Orussidae . The three groupings have been distinguished by
Xyelidae - Misplaced Pages Continue
2464-507: The Diprionidae, such as the pine sawflies, Diprion pini and Neodiprion sertifer , cause serious damage to pines in regions such as Scandinavia. D. pini larvae defoliated 500,000 hectares (1,200,000 acres) in the largest outbreak in Finland, between 1998 and 2001. Up to 75% of the trees may die after such outbreaks, as D. pini can remove all the leaves late in the growing season, leaving
2541-600: The North American species of Xyela by Burdick (1961), the North American species of Pleroneura by Smith et al. (1977), the East Asian species of Megaxyela by Shinohara (1992), the East Asian species of Pleroneura by Shinohara (1995), and the species of Megaxyela of the World by Blank et al. (2017). The Electronic World Catalog of Symphyta provides a complete account of the valid fossil genera and species, their synonyms and
2618-505: The Symphyta gave rise to the monophyletic suborder Apocrita ( wasps , bees , and ants ). In cladistic analyses the Orussoidea are consistently the sister group to the Apocrita. The oldest unambiguous sawfly fossils date back to the Middle or Late Triassic. These fossils, from the family Xyelidae , are the oldest of all Hymenoptera. One fossil, Archexyela ipswichensis from Queensland
2695-399: The abdominal prolegs are conspicuous and consist of two articles, while in the mining species ( Pleroneura , Xyela ) they are reduced to inconspicuous transverse bulges. Unique among the Hymenoptera, the pupa of Xyelidae are of the decticous and exarate types, in which the antennae, legs and mandibles are free and mobile. This stage represents the already developed ( pharate ) imago which
2772-478: The absence of a wasp waist (thorax and abdomen abut without constriction), presence of cenchri on the metathorax to fix the wings at rest, presence of an antennal grooming apparatus on tibia and first tarsomere of the fore leg, and presence of a molar tooth on the mandible. Most intriguing is the morphology of the antenna which bears a long and thick third article followed by a number of shorter and more slender antennomeres . This so-called synantennomere 3
2849-474: The adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles , adults are immobile but their larvae are mobile, and use their mobile larval form to distribute themselves. These larvae used for dispersal are either planktotrophic (feeding) or lecithotrophic (non-feeding) . Some larvae are dependent on adults to feed them. In many eusocial Hymenoptera species,
2926-460: The basal lineages of Lepidoptera . The Hymenoptera excluding Xyelidae are characterized by immobile adecticous pupae. The larvae of all Xyelidae are phytophagous and associated with trees. Larvae of the comparatively species-rich Xyela live inside the growing staminate cones of pines and feed on the sporophylls and the pollen. The North American Xyela gallicaulis is exceptional in causing galls on fresh shoots of some pine species, inside which
3003-632: The bodies directing in opposite direction. In Xyelinae the genital capsule of the males are revolved for 180° after disclosure from the pupal skin ( strophandry ). Macroxyelinae are orthandrous after emergence. They mate in the same position as Xyelinae, but the male genital capsule is rotated yet in course of mating (facultative strophandry). Like in many other sawflies, the larvae of Xyelidae are superficially similar to caterpillars of Lepidoptera (" eruciform " type of larvae). Larvae of species feeding inside plants are whitish, those of free-feeding species whitish green or yellow. Larvae of Megaxyela bear
3080-444: The case of smaller primitive arachnids, the larval stage differs by having three instead of four pairs of legs. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs . By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with
3157-429: The chicks of several birds, including partridges . Sawfly and moth larvae form one third of the diet of nestling corn buntings ( Emberiza calandra ), with sawfly larvae being eaten more frequently on cool days. Black grouse ( Tetrao tetrix ) chicks show a strong preference for sawfly larvae. Sawfly larvae formed 43% of the diet of chestnut-backed chickadees ( Poecile rufescens ). Small carnivorous mammals such as
Xyelidae - Misplaced Pages Continue
3234-417: The concerning references to original descriptions. Genus without classification into a subfamily of Xyelidae † Archexyelinae Macroxyelinae † Madygellinae Xyelinae Sawflies Sawflies are wasp -like insects that are in the suborder Symphyta within the order Hymenoptera , alongside ants, bees, and wasps. The common name comes from the saw-like appearance of the ovipositor , which
3311-462: The dorsal portions of the compound eyes. The tentorium comprises the whole inner skeleton of the head. Three segments make up the thorax: the mesothorax , metathorax and prothorax , as well as the exoskeletal plates that connect with these segments. The legs have spurs on their fourth segments, the tibiae. Sawflies have two pairs of translucent wings. The fore and hind wings are locked together with hooks. Parallel development in sawfly wings
3388-418: The eggs have hatched, some species such as the small brown sawfly will remain with them and protects the eggs by buzzing loudly and beating her wings to deter predators. There are six larval stages that sawflies go through, lasting 2 – 4 months, but this also depends on the species. When fully grown, the larvae emerge from the trees en masse and burrow themselves into the soil to pupate. During their time outside,
3465-899: The family Eulophidae attack sawflies, although their impact is low. Two species in the genus Pediobius have been studied; the two species are internal larval parasitoids and have only been found in the northern hemisphere. Parasitism of sawflies by eulophids in grass exceeds 50%, but only 5% in wheat. It is unknown as to why the attack rate in wheat is low. Furthermore, some fungal and bacterial diseases are known to infect eggs and pupa in warm wet weather. Outbreaks of certain sawfly species, such as Diprion polytomum , have led scientists to investigate and possibly collect their natural enemies to control them. Parasites of D. polytomum have been extensively investigated, showing that 31 species of hymenopterous and dipterous parasites attack it. These parasites have been used in successful biological control against pest sawflies, including Cephus cinctus throughout
3542-518: The family is supported by numerous fossil records. All Hymenoptera recorded from the Triassic are classified as Xyelidae, while representatives of other hymenopterous families have been found no earlier than the Jurassic . During the Mesozoic and the Tertiary , the Xyelidae obviously were much more species-rich and more widely distributed than today. Thus, the comparatively few extant species can be regarded
3619-467: The females use to cut into the plants where they lay their eggs. The name is associated especially with the Tenthredinoidea , by far the largest superfamily in the suborder, with about 7,000 known species; in the entire suborder, there are 8,000 described species in more than 800 genera. Symphyta is paraphyletic , consisting of several basal groups within the order Hymenoptera, each one rooted inside
3696-567: The genus Collyria . Unlike braconids, the larvae are endoparasitoids, meaning that the larvae live and feed inside the hosts body. One well known ichneumonid is Collyria coxator , which is a dominant parasitoid of C. pygmaeus . Recorded parasitism rates in Europe are between 20–76%, and as many as eight eggs can be found in a single larva, but only one Collyria individual will emerge from its host. The larva may remain inside of their host until spring, where it emerges and pupates. Several species in
3773-699: The group's distinctive lack of a wasp waist between prostomium and peristomium. Its common name, "sawfly", derives from the saw -like ovipositor that is used for egg-laying, in which a female makes a slit in either a stem or plant leaf to deposit the eggs. The first known use of this name was in 1773. Sawflies are also known as "wood-wasps". In his original description of Hymenoptera in 1863, German zoologist Carl Gerstaecker divided them into three groups, Hymenoptera aculeata , Hymenoptera apocrita and Hymenoptera phytophaga . However, four years later in 1867, he described just two groups, H. apocrita syn. genuina and H. symphyta syn. phytophaga . Consequently,
3850-559: The growth of Sakhalin spruce , since the larvae destroy the young shoots. Larvae of Megaxyela major (and supposedly also of Megaxyela langstoni ) feed on leaves of pecan and are regarded as a pest of pecan plantations in the Southeastern USA. Xyelidae represent the most basal lineage of Hymenoptera and very likely the sister taxon of all other extant Hymenoptera. This assertion is supported by phylogenetic analyses of both morphological characters and DNA sequences. The great age of
3927-524: The historical superfamilies. Such classifications were replaced by those using molecular methods, starting with Dowton and Austin (1994). As of 2013, the Symphyta are treated as nine superfamilies (one extinct) and 25 families. Most sawflies belong to the Tenthredinoidea superfamily, with about 7,000 species worldwide. Tenthredinoidea has six families, of which Tenthredinidae is by far the largest with some 5,500 species. Extinct taxa are indicated by
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#17328525630024004-593: The hosts body; braconids have more of an impact on sawfly populations in the New World than they do in the Old World, possibly because there are no ichneumonid parasitoids in North America. Some braconid wasps that attack sawflies include Bracon cephi , B. lisogaster , B. terabeila and Heteropilus cephi . Female braconids locate sawfly larvae through the vibrations they produce when feeding, followed by inserting
4081-602: The largest known sawfly measured 55 mm ( 2 + 1 ⁄ 4 in). The larvae are caterpillar-like, but can be distinguished by the number of prolegs and the absence of crochets in sawfly larvae. The great majority of sawflies are plant-eating , though the members of the superfamily Orussoidea are parasitic . Predators include birds, insects and small animals. The larvae of some species have anti-predator adaptations such as regurgitating irritating liquid and clustering together for safety in numbers. Sawflies are hosts to many parasitoids, most of which are Hymenoptera,
4158-536: The larva feeds. Larvae of Pleroneura feed inside young shoots of firs . Only the Japanese Pleroneura piceae is associated with spruce . Larvae of Macroxyelinae are free feeders of deciduous tree species. The two North American species of Macroxyela feed on elms , the East Asian and North American species of Megaxyela on Juglandaceae like walnuts , hickory and wingnuts . For Xyelecia nearctica an endophagous life style and an association with firs
4235-407: The larvae are fed by female workers. In Ropalidia marginata (a paper wasp) the males are also capable of feeding larvae but they are much less efficient, spending more time and getting less food to the larvae. The larvae of some organisms (for example, some newts ) can become pubescent and do not develop further into the adult form. This is a type of neoteny . It is a misunderstanding that
4312-416: The larvae can be quickly dispatched by simply dropping foliage into a vessel of plain or saltwater, diluted hydrogen peroxide or isopropyl alcohol, insecticidal soap, or other garden chemical. In large-scale, industrial settings, where beneficial insect predators can also be used to eliminate larvae, as well as parasites, which have both been previously used in control programs. Small trees can be sprayed with
4389-403: The larvae from the leaves they are on. Larvae typically try to remain hidden on the underside of foliage. Upon removing larvae and/or the affected leaves from plants, they may be dispatched by squishing, or, alternatively, the cut leaves with larvae still attached may be fed to birds; if larger animals do not prey upon them, other insects will. However, this is not practical or useful for some, thus
4466-428: The larvae hosts; they have mouth pieces adapted to these types of feeding. Sawflies go through a complete metamorphosis with four distinct life stages – egg, larva, pupa and adult. The female uses her ovipositor to drill into plant material (or, in the case of Orussoidea, other insects) and then lays eggs in groups called rafts or pods. After hatching, larvae feed on plants, often in groups. As they approach adulthood,
4543-417: The larvae may link up to form a large colony if many other individuals are present. They gather in large groups during the day which gives them protection from potential enemies, and during the night they disperse to feed. The emergence of adults takes awhile, with some emerging anywhere between a couple months to 2 years. Some will reach the ground to form pupal chambers, but others may spin a cocoon attached to
4620-519: The larvae seek a protected spot to pupate, typically in bark or the soil. Large populations of species such as the pine sawfly can cause substantial damage to economic forestry , while others such as the iris sawfly are major pests in horticulture . Outbreaks of sawfly larvae can defoliate trees and may cause dieback, stunting or death. Sawflies can be controlled through the use of insecticides, natural predators and parasitoids, or mechanical methods. Sawflies first appeared 250 million years ago in
4697-520: The larval form always reflects the group's evolutionary history . This could be the case, but often the larval stage has evolved secondarily, as in insects. In these cases , the larval form may differ more than the adult form from the group's common origins. Within Insects , only Endopterygotes show complete metamorphosis, including a distinct larval stage. Several classifications have been suggested by many entomologists , and following classification
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#17328525630024774-511: The name Symphyta is given to Gerstaecker as the zoological authority . In his description, Gerstaecker distinguished the two groups by the transfer of the first abdominal segment to the thorax in the Apocrita , compared to the Symphyta. Consequently, there are only eight dorsal half segments in the Apocrita, against nine in the Symphyta. The larvae are distinguished in a similar way. The Symphyta have therefore traditionally been considered, alongside
4851-523: The oldest lineages of insects and include still extant forms. The extant species occur in the Northern Hemisphere, especially in boreal regions of the Holarctic , though there are a few Oriental species. Two genera and about 15 species occur in Europe. Considering additional fossil records from Australia, South Africa and Argentina, the extant species display a relict distribution. The species in
4928-504: The ovipositor can be mistaken for a stinger. Most sawflies are stubby and soft-bodied, and fly weakly. Sawflies vary in length: Urocerus gigas , which can be mistaken as a wasp due to its black-and-yellow striped body, can grow up to 20 mm ( 3 ⁄ 4 in) in length, but among the largest sawflies ever discovered was Hoplitolyda duolunica from the Mesozoic, with a body length of 55 mm ( 2 + 1 ⁄ 4 in) and
5005-583: The ovipositors of these species (such as the family Siricidae ) are specially adapted for the task of drilling through bark. Once the incision has been made, the female will lay as many as 30 to 90 eggs. Females avoid the shade when laying their eggs because the larvae develop much slower and may not even survive, and they may not also survive if they are laid on immature and glaucous leaves. Hence, female sawflies search for young adult leaves to lay their eggs on. These eggs hatch in two to eight weeks, but such duration varies by species and also by temperature. Until
5082-511: The ovipostior and paralysing the larva before laying eggs inside the host. These eggs hatch inside the larva within a few days, where they feed on the host. The entire host's body may be consumed by the braconid larvae, except for the head capsule and epidermis . The larvae complete their development within two or three weeks. Ten species of wasps in the family Ichneumonidae attack sawfly populations, although these species are usually rare. The most important parasitoids in this family are species in
5159-493: The previous group, ending with the Apocrita which are not sawflies. The primary distinction between sawflies and the Apocrita – the ants, bees, and wasps – is that the adults lack a "wasp waist", and instead have a broad connection between the abdomen and the thorax . Some sawflies are Batesian mimics of wasps and bees, and the ovipositor can be mistaken for a stinger . Sawflies vary in length, most measuring 2.5 to 20 millimetres ( 3 ⁄ 32 to 25 ⁄ 32 in);
5236-629: The prolegs of both larvae gradually disappear by the time they burrow into the ground, therefore making it difficult to distinguish the two; and sawfly larvae only have a single pair of minute eyes, whereas lepidopteran larvae have four to six eyes on each side of the head. Sawfly larvae behave like lepidopteran larvae, walking about and eating foliage. Some groups have larvae that are eyeless and almost legless; these larvae make tunnels in plant tissues including wood. Many species of sawfly larvae are strikingly coloured, exhibiting colour combinations such as black and white while others are black and yellow. This
5313-679: The pupae. The larvae have several anti-predator adaptations . While adults are unable to sting, the larvae of species such as the spitfire sawfly regurgitate a distasteful irritating liquid, which makes predators such as ants avoid the larvae. In some species, the larvae cluster together, reducing their chances of being killed, and in some cases form together with their heads pointing outwards or tap their abdomens up and down. Some adults bear black and yellow markings that mimic wasps. Sawflies are hosts to many parasitoids, most of which are parasitic Hymenoptera; more than 40 species are known to attack them. However, information regarding these species
5390-405: The rest being Diptera . Adult sawflies are short-lived, with a life expectancy of 7–9 days, though the larval stage can last from months to years, depending on the species. Parthenogenetic females, which do not need to mate to produce fertilised eggs, are common in the suborder, though many species have males. The adults feed on pollen, nectar, honeydew, sap, other insects, including hemolymph of
5467-488: The species included in Megaxyela and Pleroneura are truly oligophagous. After completing feeding, Xyelidae larvae dig into the ground and form an earthen cell, where they usually spin a cocoon and develop into a pupa. Absence of a cocoon has been observed in Megaxyela togashii from Japan. The imago emerges in the following spring to mate. Subsequently, the female deposits eggs with the ovipositor. In most species of Xyela ,
5544-415: The subfamily Xyelinae are associated with conifers (esp. Pinus and Abies ), where the larvae feed on pollen or within buds. The larvae of the subfamily Macroxyelinae feed on the leaves of deciduous trees (various Juglandaceae and Ulmus ). The family is characterized by the appendages of the head, which are remarkable in that the antennae and palpi are nearly leg-like in structure, with
5621-435: The subtropical parts of Asia. Sawflies are mostly 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. The larvae primarily feed in groups; they are folivores , eating plants and fruits on native trees and shrubs, though some are parasitic. However, this
5698-495: The tip of valvula 3 of the ovipositor sheath is equipped with specialized sensory structures called sensilla trichodea and sensilla campaniformia , which are involved in the oviposition process. In Pleroneura , unlike practically all other Hymenoptera, the hard and conical ovipositor sheath is used in addition to the ovipositor proper to penetrate the resinous buds of firs. Megaxyela gigantea and most other species of Megaxyela has strikingly long hind legs which are used to fold
5775-522: The trees too weak to survive the winter. Little damage to trees only occurs when the tree is large or when there is minimal presence of larvae. Eucalyptus trees can regenerate quickly from damage inflicted by the larvae; however, they can be substantially damaged from outbreaks, especially if they are young. The trees can be defoliated completely and may cause "dieback", stunting or even death. Sawflies are serious pests in horticulture . Different species prefer different host plants, often being specific to
5852-496: The true sawflies' 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 beetles . The woodwasps themselves are a paraphyletic ancestral grade . Despite these limitations, the terms have utility and are common in the literature. While most hymenopteran superfamilies are monophyletic , as
5929-452: The veins Rs1 and Rs2 , while in other Hymenoptera Rs1 is absent. The females bear a more or less long ovipositor , which in some species of Xyela may be as long as the body. Morphology of the ovipositor and the ovipositor sheath are important characters for identification to species level. The penis valves of the males are densely setulous, which is a rare character state among the basal lineages of Hymenoptera. Females and males mate with
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