![GrassHopperOviPositor](https://upload.wikimedia.org/wikipedia/commons/4/4b/GrassHopperOviPositor.jpg)
The ovipositor is a tube-like
organ used by some
animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
s, especially insects, for the laying of
eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
. 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 most insects, the organ is used merely to attach the egg to some surface, but for many
parasitic
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...
species (primarily in
wasp
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. ...
s 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".
In insects
Grasshoppers use their ovipositors to force a burrow into the earth to receive the eggs.
Cicada
The cicadas () are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two ...
s pierce the
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...
of twigs with their ovipositors to insert the eggs.
Sawflies
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 ...
slit the
tissues of
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...
s by means of the ovipositor and so do some species of
long-horned grasshoppers. In the ichneumon wasp genus ''
Megarhyssa
''Megarhyssa'', also known as giant ichneumonid wasps, giant ichneumons, or stump stabbers, 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 ...
'', the females have a slender ovipositor (terebra) several inches long that is used to drill into the wood of
tree trunks
In botany, the trunk (or bole) is the stem and main wooden axis of a tree, which is an important feature in tree identification, and which often differs markedly from the bottom of the trunk to the top, depending on the species. The trunk is the ...
. These species are parasitic in the
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
...
l stage on the larvae of
horntail
Horntail or wood wasp are any of the 150 non-social species of the hymenopteran family Siricidae, a type of wood-eating sawfly. The common name "horntail" derives from the stout, spine-like structure at the end of the adult's abdomen, which is u ...
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.
The
stinger
A stinger (or sting) is a sharp organ found in various animals (typically insects and other arthropods) capable of injecting venom, usually by piercing the epidermis of another animal.
An insect sting is complicated by its introduction of ve ...
s of the
Aculeata
Aculeata is a subclade of Hymenoptera containing ants, bees, and stinging wasps. The name is a reference to the defining feature of the group, which is the modification of the ovipositor into a stinger. However, many members of the group canno ...
(wasps, hornets, bees, and ants) are ovipositors, highly modified and with associated
venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a st ...
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. However, in virtually all stinging
Hymenoptera, the ovipositor is no longer used for egg-laying. An exception is the family
Chrysididae
Commonly known as cuckoo wasps or emerald wasps, the hymenopteran family Chrysididae is a very large cosmopolitan group (over 3000 described species) of parasitoid or kleptoparasitic wasps, often highly sculptured, with brilliant metallic colors ...
, members of the Hymenoptera, in which species such as ''
Chrysis ignita
''Chrysis ignita'' is a species of cuckoo wasp. It is one of a group of species which are difficult to separate and which may be referred to as ruby-tailed wasps. Cuckoo wasps are kleptoparasites – they lay their eggs in the nests of other spec ...
'' have reduced stinging apparatus and a functional ovipositor.
Fig wasp
Fig wasps are wasps of the superfamily Chalcidoidea which spend their larval stage inside figs. Most are pollinators but others simply feed off the plant. The non-pollinators belong to several groups within the superfamily Chalcidoidea, while the ...
ovipositors have specialized serrated teeth to penetrate fruits, but
gall wasp
Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this gener ...
s have either uniform teeth or no teeth on their ovipositors, meaning the
morphology of the organ is related to the life history.
Members of the
Dipteran (fly) families
Tephritidae
The Tephritidae are one of two fly families referred to as fruit flies, the other family being the Drosophilidae. The family Tephritidae does not include the biological model organisms of the genus ''Drosophila'' (in the family Drosophilidae), ...
and
Pyrgotidae
The Pyrgotidae are an unusual family of flies (Diptera), one of only two families of Cyclorrhapha that lack ocelli. Most species are "picture-winged" (i.e., have patterns of bands or spots on the wings), as is typical among the Tephritoidea, but ...
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
''Cuterebra fontinella'', the mouse bot fly, is a species of New World skin bot fly in the family Oestridae. ''C. fontinella'' is typically around in length with a black and yellow color pattern. ''C. fontinella'' develops by parasitizing nutrien ...
'' has one of the shortest within the family.
Ovipositors exist not only in
winged insects, but also in
Apterygota
The name Apterygota is sometimes applied to a subclass of small, agile insects, distinguished from other insects by their lack of wings in the present and in their evolutionary history; notable examples are the silverfish, the firebrat, and the ...
, 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.
In fish
Female bitterlings in the genus ''
Rhodeus
''Rhodeus'' is a genus of cyprinid fish, consisting of 23 species called bitterlings. The scientific name is derived from the Greek word ', meaning "rose". Most species in the genus are restricted to Asia, but two species are found in Europe (' ...
'' have an ovipositor in the form of a tubular extension of the
genital
A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...
orifice. During breeding season, they use it when depositing eggs in the mantle cavity of freshwater
mussel
Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...
s, where their eggs develop in reasonable security.
Seahorse
A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine fish in the genus ''Hippocampus''. "Hippocampus" comes from the Ancient Greek (), itself from () meaning "horse" and () meaning "sea monster" or " ...
s 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.
In Amphibians
The
marbled newt
The marbled newt (''Triturus marmoratus'') is a mainly terrestrial newt native to western Europe. They are found in the Iberian Peninsula and France, where they typically inhabit mountainous areas.
Habitat and distribution
The marbled newt is ty ...
, or ''Triturus marmoratus,'' females participate in parental investment by ovipositing their eggs. They carefully wrap them in aquatic leaves as a form of protection, scattering them throughout a pond to avoid predation. Females are not able to breath during the oviposition process; therefore the benefit to wrapping the eggs outweigh the cost of holding their breath.
File:Urophora.cardui.female.jpg, A female fly in the family Tephritidae
The Tephritidae are one of two fly families referred to as fruit flies, the other family being the Drosophilidae. The family Tephritidae does not include the biological model organisms of the genus ''Drosophila'' (in the family Drosophilidae), ...
, with the ovipositor retracted and only the scape showing.
File:Anastrepha ludens 1322089.jpg, Ovipositing Mexican fruit flies showing the scapes of the extended ovipositors.
File:Megarhyssa.jpg, Female ''Megarhyssa
''Megarhyssa'', also known as giant ichneumonid wasps, giant ichneumons, or stump stabbers, 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 ...
'' laying eggs with her ovipositor.
References
External links
* {{Commonscatinline
Animal reproductive system
Fish anatomy
Insect anatomy