Ovipositor

The ovipositor is an organ used by some animals for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typically its form is adapted to functions such as transmitting the egg, preparing a place for it, and placing it properly. For insects, the organ is used merely to attach the egg to some surface, but for many parasitic species (primarily in wasps and other Hymenoptera), it is a piercing organ as well.

Some ovipositors only retract partly when not in use, and the basal part that sticks out is known as the scape, or more specifically oviscape, the word scape deriving from the Latin word scāpus, meaning "stalk" or "shaft".

GrassHopperOviPositor
Ovipositor of Long-horned Grasshopper (the two cerci are also visible)

In insects

Dolichomitus imperator Oviposition R Bartz

The process of oviposition in Dolichomitus imperator:
1. Tapping with her antennae, the wasp listens for the vibrations that indicate a host is present
2. With the longer ovipositor, the wasp drills a hole through the bark
3. The wasp inserts the ovipositor into the cavity which contains the host larva
4. Making corrections
5-6. Depositing the eggs

Grasshoppers use their ovipositors to force a burrow into the earth to receive the eggs. Cicadas pierce the wood of twigs with their ovipositors to insert the eggs. Sawflies slit the tissues of plants by means of the ovipositor and so do some species of long-horned grasshoppers. In the wasp genus Megarhyssa, the females have a slender ovipositor (terebra) several inches long that is used to drill into the wood of tree trunks.[1] These species are parasitic in the larval stage on the larvae of horntail wasps, hence the egg must be deposited directly into the host's body as it is feeding. The ovipositor of the giant ichneumon wasp is the longest egg-laying organ known among biologists.[2]

The stings of the Aculeata (wasps, hornets, bees, and ants) are ovipositors, highly modified and with associated venom glands. They are used to paralyze prey, or as defensive weapons. The penetrating sting plus venom allows the wasp to lay eggs with less risk of injury from the host. In some cases the injection also introduces virus particles that suppress the host's immune system and prevent it from destroying the eggs.[3] However, in virtually all stinging Hymenoptera, the ovipositor is no longer used for egg-laying. An exception is the family Chrysididae, members of the Hymenoptera, in which species such as Chrysis ignita have reduced stinging apparatus and a functional ovipositor.

Members of the Dipteran (fly) families Tephritidae and Pyrgotidae have well-developed ovipositors that are partly retracted when not in use, with the part that sticks out being the oviscape.

In fish

Female bitterlings in the genus Rhodeus have an ovipositor in the form of a tubular extension of the genital orifice. During breeding season, they use it when depositing eggs in the mantle cavity of freshwater mussels, where their eggs develop in reasonable security. Seahorses have an ovipositor for introducing eggs into the brood pouch of the male, who carries them until it is time to release the fry into a suitable situation in the open water.

Gallery

Urophora.cardui.female

A female fly in the family Tephritidae, with the ovipositor retracted and only the scape showing.

Anastrepha ludens 1322089

Ovipositing Mexican fruit flies showing the scapes of the extended ovipositors.

Megarhyssa

Female Megarhyssa laying eggs with her ovipositor.

References

  1. ^ Sezen, Uzay. "Two ichneumon wasps competing to oviposit". Retrieved 24 July 2012.
  2. ^ Sezen, Uzay. "Giant ichneumon wasp ovipositing". Retrieved 15 February 2016.
  3. ^ "Evolution Makes Sense of Homologies".
Aculeata

Aculeata is a subclade of Hymenoptera. The name is a reference to the defining feature of the group, which is the modification of the ovipositor into a stinger (thus, the group could be called "stinging wasps", though the group also contains the ants and the bees). In other words, the structure that was originally used to lay eggs is modified instead to deliver venom. Not all members of the group can sting; a great many cannot, either because the ovipositor is modified in a different manner (such as for laying eggs in crevices), or because it is lost altogether. A large part of the clade is parasitic.

This group includes the bees and ants and all of the eusocial Hymenopterans. It is commonly believed that the possession of a venomous sting was one of the important features promoting the evolution of social behavior, as it confers a level of anti-predator defense rarely approached by other invertebrates.

Apocrita

The Apocrita are a suborder of insects in the order Hymenoptera. It includes wasps, bees, and ants, and consists of many families. It contains the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" (petiole) formed between the first two segments of the actual abdomen; the first abdominal segment is fused to the thorax, and is called the propodeum. Therefore, it is general practice, when discussing the body of an apocritan in a technical sense, to refer to the mesosoma and metasoma (or "gaster") rather than the "thorax" and "abdomen", respectively. The evolution of a constricted waist was an important adaption for the parasitoid lifestyle of the ancestral apocritan, allowing more maneuverability of the female's ovipositor. The ovipositor either extends freely or is retracted, and may be developed into a stinger for both defense and paralyzing prey. Larvae are legless and blind, and either feed inside a host (plant or animal) or in a nest cell provisioned by their mothers.

The Apocrita have historically been split into two groups, "Parasitica" and Aculeata, but these are rankless groupings in present classifications, if they appear at all. The term Parasitica is an artificial (paraphyletic) group comprising the majority of hymenopteran insects, with respective members living as parasitoids on what amounts to nearly half of all insects, and many noninsects. Most species are small, with the ovipositor adapted for piercing. In some hosts, the parasitoids induce metamorphosis prematurely, and in others it is prolonged. There are even species that are hyperparasites, parasitoids on other parasitoids. The Parasitica lay their eggs inside or on another insect (egg, larva or pupa) and their larvae grow and develop within or on that host. The host is nearly always killed. Many parasitic hymenopterans are used as biological control agents to control pests, such as caterpillars, true bugs and hoppers, flies, and weevils.The Aculeata are a monophyletic group that includes those species in which the female's ovipositor is modified into a stinger to inject venom. Groups include the familiar ants, bees, and various types of parasitic and predatory wasps; it also includes all of the social hymenopterans.Among the nonparasitic and nonsocial Aculeata, larvae are fed with captured prey (typically alive and paralyzed) or may be fed pollen and nectar. The social Aculeata feed their young prey (paper wasps and hornets), or pollen and nectar (bees), or perhaps seeds, fungi, or nonviable eggs (ants).

Cecidosidae

Cecidosidae is a little-known family of primitive monotrysian moths in the order Lepidoptera which have a piercing ovipositor used for laying eggs in plant tissue in which they induce galls, or they mine in bark (Davis, 1999; Hoare and Dugdale, 2003). Nine species occur in southern Africa, five species in South America (Parra, 1998) and Xanadoses nielseni was recently described from New Zealand (Hoare and Dugdale, 2003). Some minute parasitoid wasps are known (Burks et al., 2005).

Ensifera

Ensifera is a suborder of insects that includes the various types of crickets and their allies including: true crickets, camel crickets, bush crickets or katydids, grigs, wetas and Cooloola monsters. It and the suborder Caelifera (grasshoppers and their allies) make up the order Orthoptera. Ensifera is believed to be a more ancient group than Caelifera, with its origins in the Carboniferous period, the split having occurred at the end of the Permian period. Unlike the Caelifera, the Ensifera contain numerous members that are partially carnivorous, feeding on other insects as well as plants.

"Ensifer" is Latin for "sword bearer", and refers to the typically elongated and blade-like ovipositor of the females.

Field cricket

Field crickets are insects of order Orthoptera. These crickets are in subfamily Gryllinae of family Gryllidae.

They hatch in spring, and the young crickets (called nymphs) eat and grow rapidly. They shed their skin (molt) eight or more times before they become adults.

Field crickets eat a broad range of feeds: seeds, plants, or insects (dead or alive). They are known to feed on grasshopper eggs, pupae of Lepidoptera (moths and butterflies) and Diptera (flies). Occasionally they may rob spiders of their prey. Field crickets also eat grass.

"Field cricket" is a common name for Gryllus assimilis, G. bimaculatus, G. campestris, G. firmus, G. pennsylvanicus, G. rubens, and G. texensis, along with other members of various genera including Acheta, Gryllodes, Gryllus, and Teleogryllus.

Acheta domesticus, the House cricket, and Gryllus bimaculatus are raised in captivity for use as pets.

Horntail

Horntail or wood wasp is the common name for any of the 150 non-social species of the family Siricidae, of the order Hymenoptera, a type of xylophagous sawfly. This family was formerly believed to be the sole living representative of the superfamily Siricoidea, a group well represented in Paleogene and Mesozoic times, but the family Anaxyelidae has been linked to this group as well. Siricidae has two sub families, Siricinae and Tremecinae. Siricinae infest needle-leaved trees and Tremecinae infest broad-leaved trees. There are ten living genera placed in the family, and an additional three genera described from fossils. The last tergite of the abdomen has a strong, projecting spike, thus giving the group its common name (the ovipositor is typically longer and also projects posteriorly, but it is not the source of the name). A typical adult horntail is brown, blue, or black with yellow parts, and may often reach up to 4 cm (1.6 in) long. The pigeon horntail (Tremex columba) can grow up to 5 cm (2.0 in) long (not counting the ovipositor), among the longest of all Hymenoptera.

Female horntails lay their eggs in trees. The larvae bore into the wood and live in the tree for up to two years, possibly more. They typically migrate to just under the bark before pupation.

The spiral groove on the ovipositor is visible on the photograph but not easily to the naked eye.

Hymenoptera

Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones.Females typically have a special ovipositor for inserting eggs into hosts or places that are otherwise inaccessible. The ovipositor is often modified into a stinger. The young develop through holometabolism (complete metamorphosis)—that is, they have a worm-like larval stage and an inactive pupal stage before they mature.

Incurvarioidea

Incurvarioidea is a superfamily of primitive monotrysian moths in the order Lepidoptera which consists of Leafcutters, yucca moths and relatives. This superfamily is characterised by a piercing, extensible ovipositor used for laying eggs in plants (Davis, 1999). Many species are day-flying with metallic patterns.

Macromiidae

The insect family Macromiidae contains the dragonfly species known as cruisers or skimmers. They tend to fly over bodies of water (and roads) straight down the middle. They are similar to Aeshnidae in size, but the eyes are green and just barely meet at the top of the head.

Macromiidae, or Macromiinae, has been traditionally considered as a subfamily of Corduliidae (Kirby, 1890). It contains four genera and 125 species worldwide.

Females of this family lack an ovipositor at the end of the abdomen and lay their eggs by dipping the abdomen in the water as they fly over. Ovipositing is usually done without a male.

Naiads are found in rivers, streams, and lakes where there is water movement. They crawl in debris at the water's bottom and wait for prey.

Megalyridae

Megalyroidea is a small hymenopteran superfamily that includes a single family, Megalyridae, with eight genera (plus three extinct ones) and 49 described species. Modern megalyrids are found primarily in the southern hemisphere, though fossils have only been found in the northern hemisphere. The most abundant and species-rich megalyrid fauna is in Australia. Another peak of diversity appears to be in the relict forests of Madagascar, but most of these species are still undescribed.

Historically, there has been much confusion about the definition of this family. Species now placed in Megalyridae have in the past been classified into as many as six other families (Braconidae, Evaniidae, Ichneumonidae, and Stephanidae, as well as Dinapsidae and Maimetshidae, the latter two now considered ranks within the Megalyridae).

The best defining feature, unique to the family, is the mesothoracic spiracle has moved, and is actually located in the upper corner of the pronotum, though this is a fairly obscure feature to see. Perhaps the most useful visible character is that the base of the antenna fits into a wide, concave groove below the eye, though a few other wasp families exhibit this trait. Females of Megalyra have ovipositors ranging from five to eight times their body length, but this is not true of the other genera.The largest known megalyrid is the female of the Australian Megalyra shuckardi, with a body length of 22 mm (0.9 in) and ovipositor length of 82 mm (3.2 in). The smallest known megalyrid is the Brazilian Cryptalyra plaumanni, with a body length of 2.9 mm (0.1 in) and ovipositor 1 mm (0.0 in) long.

Megalyrid wasps are thought to be idiobiont endoparasitoids of concealed insect larvae. One Australian species, Megalyra troglodytes, attacks the larvae of Arpactophilus mimi, a mud-nesting crabronid wasp. Oviposition habits of Megalyridae are regarded as quite primitive, with field observations suggesting they simply poke their ovipositors into pre-existing cavities, holes, or cracks, rather than drilling into the substrate as in other Apocrita.

Megarhyssa macrurus

Megarhyssa macrurus (common name giant ichneumon wasp), is a species of large ichneumon wasp.It is a parasitoid, notable for its extremely long ovipositor which it uses to deposit an egg into a tunnel in dead wood bored by its host, the larva of a similarly large species of horntail. Another of its common names is stump stabber referring to this behaviour.

Orthopterida

The Orthopterida is a superorder of the Polyneoptera that represents the extant orders Orthoptera (grasshoppers, crickets, and katydids), and Phasmatodea (stick insects and leaf insects). The Orthopterida also includes the extinct orders Titanoptera and Caloneurodea. There is general consensus of monophyly in this superorder, based on reduction of the second valvulae, an ovipositor derived from the gonoplac, and an enlarged precostal region on the forewing.

The two other superorders of the Polyneoptera are the Plecopterida, which represents the orders Plecoptera (stoneflies), Emboidea (Embioptera/Embiidina; webspinners), and Zoraptera (angel insects), and the Dictyoptera, which represents Blattodea (cockroaches & termites), and Mantodea (mantids). Two other orders, the Notoptera (ice-crawlers and gladiators) and Dermaptera (earwigs) are also placed in the Polyneoptera but outside the superorders discussed above.

Panorpida

Panorpida or Mecopterida is a proposed superorder of Endopterygota. The conjectured monophyly of the Panorpida is historically based on morphological evidence, namely the reduction or loss of the ovipositor and several internal characteristics, including a muscle connecting a pleuron and the first axillary sclerite at the base of the wing, various features of the larval maxilla and labium, and basal fusion of CuP and A1 veins in the hind wings. The monophyly of the Panorpida is also supported by recent molecular data.

Platygastroidea

The Hymenopteran superfamily of parasitoid wasps, Platygastroidea, has often been treated as a lineage within the superfamily Proctotrupoidea, but most classifications since 1977 have recognized it as an independent group. It is composed of two families, the Platygastridae and the Scelionidae, with a combined diversity of some 4000 described species. The two groups are unified by a number of features, the most important of which are shared unique features synapomorphies of the ovipositor and details of the female antenna. They are exclusively parasitic in nature. See families for details.

The former family Scelionidae is now considered to be a subfamily of the Platygastridae, along with the subfamilies Teleasinae and Telenominae.

Pygidium

The pygidium (plural pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. It contains the anus and, in females, the ovipositor. It is composed of fused body segments, sometimes with a tail, and separated from thoracic segments by an articulation.

Richardiidae

The Richardiidae are a family of Diptera in the superfamily Tephritoidea.

This small family consists of just over 30 genera and 175 species. Almost all species are neotropical. Generally, the biology of the richardiids is little known. Some of the larvae are plant feeders or saprophages in decaying plant material. One species, the pineapple fruit fly Melanoloma viatrix, has been reported as a pest of pineapples. Most adults have some general features, conspicuously pictured wings, often with metallic blue or greenish colors on the body and legs, and a typical tephritoid ovipositor.

Sawfly

Sawflies are the insects of 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 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, with about 7,000 known species; in the entire suborder, there are 8,000 described species in more than 800 genera. The suborder Symphyta is paraphyletic, consisting of several basal groups within the order Hymenoptera.

The primary distinction between sawflies and their relatives 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 millimetres (0.1 in) to 20 millimetres (0.8 in); the largest known sawfly measured 55 millimetres (2.2 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, 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 the larvae hosts; they have mouth pieces adapated 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, 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 important 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 parasites, or mechanical methods.

Sawflies first appeared 250 million years ago in the Triassic. The oldest superfamily, the Xyeloidea, has existed into the present. 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 northern hemisphere.

Tipula

Tipula is a very large insect genus in the fly family Tipulidae. They are commonly known as crane flies or daddy longlegs. Worldwide there are well over a thousand species.

All species have very long, fragile legs. The male has a swollen tip to his abdomen, and the female has a pointed ovipositor which is used to push eggs into soil. The larvae of some species are root-feeding and may be called "leatherjackets".

Technical description: Discal cell present ; M3 arises from M4 ; all tibiae spurred Antennae with whorls of long hairs. Rs usually long ; Sc ends far from base of Rs ; cell 4 always petiolate ; body colour usually grey, brown or dull yellow, rarely black ; praescutal stripes

(when present) usually dull, rarely slightly shining

Wasp

A wasp is any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. The Apocrita have a common evolutionary ancestor and form a clade; wasps as a group do not form a clade, but are paraphyletic with respect to bees and ants.

The most commonly known wasps, such as yellowjackets and hornets, are in the family Vespidae and are eusocial, living together in a nest with an egg-laying queen and non-reproducing workers. Eusociality is favoured by the unusual haplodiploid system of sex determination in Hymenoptera, as it makes sisters exceptionally closely related to each other. However, the majority of wasp species are solitary, with each adult female living and breeding independently. Females typically have an ovipositor for laying eggs in or near a food source for the larvae, though in the Aculeata the ovipositor is often modified instead into a sting used for defense or prey capture. Wasps play many ecological roles. Some are predators or pollinators, whether to feed themselves or to provision their nests. Many, notably the cuckoo wasps, are kleptoparasites, laying eggs in the nests of other wasps. Many of the solitary wasps are parasitoidal, meaning they lay eggs on or in other insects (any life stage from egg to adult) and often provision their own nests with such hosts. Unlike true parasites, the wasp larvae eventually kill their hosts. Solitary wasps parasitize almost every pest insect, making wasps valuable in horticulture for biological pest control of species such as whitefly in tomatoes and other crops.

Wasps first appeared in the fossil record in the Jurassic, and diversified into many surviving superfamilies by the Cretaceous. They are a successful and diverse group of insects with tens of thousands of described species; wasps have spread to all parts of the world except for the polar regions. The largest social wasp is the Asian giant hornet, at up to 5 centimetres (2.0 in) in length; among the largest solitary wasps is a group of species known as tarantula hawks, along with the giant scoliid of Indonesia (Megascolia procer). The smallest wasps are solitary chalcid wasps in the family Mymaridae, including the world's smallest known insect, with a body length of only 0.139 mm (0.0055 in), and the smallest known flying insect, only 0.15 mm (0.0059 in) long.

Wasps have appeared in literature from Classical times, as the eponymous chorus of old men in Aristophanes' 422 BC comedy Σφῆκες (Sphēkes), The Wasps, and in science fiction from H. G. Wells's 1904 novel The Food of the Gods and How It Came to Earth, featuring giant wasps with three-inch-long stings. The name "Wasp" has been used for many warships and other military equipment.

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