Ovipositor

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

The ovipositor is a tube-like organ used by some animals, especially insects 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 preparing a place for the egg, transmitting the egg, and then 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.

Contents

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".

In insects

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 Dolichomitus imperator Oviposition R Bartz.jpg

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 ichneumon 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 ovipositors of Megarhyssa are among the longest egg-laying organs (relative to body size) known. [2]

The stingers 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.

Fig wasp ovipositors have specialized serrated teeth to penetrate fruits, but gall wasps have either uniform teeth or no teeth on their ovipositors, meaning the morphology of the organ is related to the life history. [4]

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. Oestridae, another family within Diptera, often have short hairy ovipositors, the species Cuterebra fontinella has one of the shortest within the family. [5]

Ovipositors exist not only in winged insects, but also in Apterygota, where the ovipositor has an additional function in gathering the spermatophore during mating. Little is known about the egg-laying habits of these insects in the wild. [6]

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.

Related Research Articles

Hornet Genus of eusocial wasp

Hornets are the largest of the eusocial wasps, and are similar in appearance to their close relatives yellowjackets. Some species can reach up to 5.5 cm (2.2 in) in length. They are distinguished from other vespine wasps by the relatively large top margin of the head and by the rounded segment of the abdomen just behind the waist. Worldwide, 22 species of Vespa are recognized. Most species only occur in the tropics of Asia, though the European hornet, is widely distributed throughout Europe, Russia, North America, and Northeast Asia. Wasps native to North America in the genus Dolichovespula are commonly referred to as hornets, but are actually yellowjackets.

Mutillidae Family of wasps

The Mutillidae are a family of more than 7,000 species of wasps whose wingless females resemble large, hairy ants. Their common name velvet ant refers to their dense pile of hair, which most often is bright scarlet or orange, but may also be black, white, silver, or gold. Their bright colors serve as aposematic signals. They are known for their extremely painful stings,, hence the common name cow killer or cow ant. However, mutillids are not aggressive and sting only in defense. In addition, the actual toxicity of their venom is much lower than that of honey bees or harvester ants. Unlike true ants, they are solitary, and lack complex social systems.

Apocrita suborder of insects

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 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 or in a nest cell provisioned by their mothers.

Ichneumonoidea superfamily of insects

The superfamily Ichneumonoidea contains one extinct and three extant families, including the two largest families within Hymenoptera: Ichneumonidae and Braconidae. The group is thought to contain as many as 100,000 species, many of which have not yet been described. Like other parasitoid wasps, they were long placed in the "Parasitica", variously considered as an infraorder or an unranked clade, now known to be paraphyletic.

Ichneumonidae family of insects

The Ichneumonidae, also known as the ichneumon wasps or ichneumonids, is a parasitoid wasp family within the insect order Hymenoptera. This insect family is among the most species-rich branches of the tree of life. At the same time, it is one of the groups for which our knowledge most severely lags behind their actual diversity. The roughly 25,000 species described today probably represent less than a quarter of their true richness, but reliable estimates are lacking, as is much of the most basic knowledge about their ecology, distribution and evolution. Ichneumonid wasps, with very few exceptions, attack the immature stages of holometabolous insects and spiders, eventually killing their hosts. They thus fulfill an important role as regulators of insect populations, both in natural and semi-natural systems, making them promising agents for biological control.

Stinger Sharp organ found in various animals capable of injecting venom

A stinger is a sharp organ found in various animals capable of injecting venom, usually by piercing the epidermis of another animal.

Hymenoepimecis argyraphaga is a Costa Rican parasitoid wasp whose host is the spider Plesiometa argyra. The wasp is unusual in modifying the spider's web building behavior to make a web made of very strong lines designed to support the wasp's cocoon without breaking in the rain.

Horntail family of insects

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. 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 can grow up to 5 cm (2.0 in) long, among the longest of all Hymenoptera.

Braconidae family of insects

The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis estimated a total between 30,000 and 50,000, and another provided a narrower estimate between 42,000 and 43,000 species.

Parasitoid wasp evolutionary grade of hymenopteran superfamilies

Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.

<i>Polistes gallicus</i> species of wasp

Polistes gallicus is a fairly common species of paper wasp found in various parts of Europe, excluding England, Denmark, and Scandinavia, from warmer climates to cooler regions north of the Alps. Nests of these social insects are created in these various conditions. The Polistes species use an oral secretion to construct their nests, which consist of a combination of saliva and chewed plant fibers. This structural mixture physically protects the nest from various harsh elements and from weathering over time.

<i>Megarhyssa</i> genus of insects

Megarhyssa is a genus of large ichneumon wasps, with some species known for having the longest ovipositors of any insects. They are idiobiont endoparasitoids of the larvae of wood-boring horntail wasps. The ovipositor can be mistaken for a large stinger.

Wasp Members of the order Hymenoptera which are not ants nor bees

A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps but are in a separate suborder. The wasps do not constitute a clade, a complete natural group with a single ancestor, as their common ancestor is shared by bees and ants. Many wasps, those in the clade Aculeata, can sting their insect prey.

<i>Xanthocryptus novozealandicus</i> species of insect

Xanthocryptus novozealandicus, the lemon tree borer parasite, is a wasp in the family Ichneumonidae. It is a native insect of New Zealand. It is also found in Australia and New Guinea. Females hunt for larvae of wood-boring beetles around March, including the lemon tree borer, a native cerambycid that tunnels into citrus trees, grapes and many native species. When a suitable host is found, the female pushes her ovipositor through the wood and injects her eggs into the grub. This has the incidental benefit of helping to control some pests. X. novozealandicus prefers to prey on second year lemon tree borer larvae. This specific parasite prefers to prey on larger second year larvae due to its larger size.

<i>Rhyssa persuasoria</i> species of insect

Rhyssa persuasoria, the giant ichneumon, is a species belonging to the family Ichneumonidae subfamily Rhyssinae.

<i>Chrysis ignita</i> species of insect

Chrysis ignita, also known as the ruby-tailed wasp, is a species of cuckoo wasps. Cuckoo wasps are kleptoparasites – they lay their eggs in the nests of other wasp species and their young consume the eggs or larva of the host wasp for sustenance. These wasps have a number of adaptions which have evolved to equip them for their life cycle. Chrysis ignita parasitize mason bees in particular. Ruby-tailed wasps have metallic, armored bodies, and can roll up into balls to protect themselves from harm when infiltrating the nests of host bees and wasps. Unlike most other Hymenopterans, cuckoo wasps cannot sting. Chrysis ignita is found across the European continent.

<i>Megarhyssa macrurus</i> species of insect

Megarhyssa macrurus, is a species of large ichneumon wasp.

<i>Pepsis grossa</i> species of insect

Pepsis grossa is a very large species of pepsine spider wasp from the southern part of North America, south to northern South America. It preys on tarantula spiders, giving rise to the name tarantula hawk for the wasps in the genus Pepsis and the related Hemipepsis. Only the females hunt, so only they are capable of delivering a sting, which is considered the second most painful of any insect sting; scoring 4.0 on the Schmidt sting pain index compared to the bullet ant's 4.0+. It is the state insect of New Mexico. The colour morphs are the xanthic orange-winged form and the melanic black winged form. In northern South America, a third form, known as "lygamorphic", has a dark base to the wings which have dark amber median patches and a pale tip.

<i>Cuterebra fontinella</i> species of insect

Cuterebra fontinella, the mouse bot fly, is a species of New World skin bot fly in the family Oestridae. C. fontinella is typically around 1 mm long with a black and yellow color pattern. C. fontinella develops by parasitizing nutrients from its host, typically the white-footed mouse. C. fontinella has even been known to parasitize humans in rare cases. Individuals parasitized by C. fontinella will develop a large bump on the skin that is indicative of parasitization.

<i>Vespula infernalis</i>

Vespula infernalis is an obligate parasitic wasp, parasitizing the nests of other species in the genus Vespula. Its common host species is V. acadica in North America. It is sometimes called the cuckoo yellowjacket wasp due to its inquiline lifestyle. They differ from other parasitic wasps in their intensely aggressive behaviour during invasion and occupation of the host colony. Several morphological adaptations such as bigger body parts and more curved sting shafts are observed in these wasps to aid their aggressive parasitic behaviour. Once they occupy a host's nest, V. infernalis are known to engage in mauling and chasing of host workers and forced trophallaxis. Female wasps will also force host workers to feed and take care of their brood.

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. "Evolutionary Genetics". www.zoology.ubc.ca.
  4. Elias, Larissa; Kjellberg, Finn; Farache, Fernando Henriche Antoniolli; Almeida, Eduardo; Rasplus, Jean-Yves; Cruaud, Astrid; Peng, Yan-Quiong; Yang, Da-Rong; Pereira, Rodrigo Augusto Santinelo (July 2018). "Ovipositor morphology correlates with life history evolution in agaonid fig wasps" (PDF). Acta Oecologica. 90: 109–116. doi:10.1016/j.actao.2017.10.007 . Retrieved 22 August 2020.
  5. Hadwen S (1915). "A description the egg and ovipositor of Cuterebra fontinella, Clark (Cottontail Bot.)". Journal of the Entomological Society of British Columbia. 5: 88–91.
  6. Matushkina, Natalia A. (January 2011). "Ovipositor Internal Microsculpture in the Relic Silverfish Tricholepidion gertschi (Insecta: Zygentoma)" (PDF). Publication:Psyche: A Journal of Entomology. Retrieved 22 August 2020.