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Theovipositor is a tube-likeorgan used by someanimals, especiallyinsects, for the laying ofeggs. 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 manyparasitic species (primarily inwasps and otherHymenoptera), it is a piercing organ as well.
Some ovipositors only retract partly when not in use, and thebasal part that sticks out is known as thescape, or more specificallyoviscape, the wordscape deriving from the Latin wordscāpus, meaning "stalk" or "shaft".
Grasshoppers use their ovipositors to force a burrow into the earth to receive the eggs.Cicadas pierce thewood of twigs with their ovipositors to insert the eggs.Sawflies slit thetissues ofplants by means of the ovipositor and so do some species oflong-horned grasshoppers. In the ichneumon wasp genusMegarhyssa, the females have a slender ovipositor (terebra) several inches long that is used to drill into the wood oftree trunks.[1] These wasps are parasitic in thelarval stage on the larvae ofhorntail wasps, hence the egg must be deposited directly into the host's body as it is feeding. The ovipositors ofMegarhyssa are among the longest egg-laying organs (relative to body size) known.[2]
Thestingers of theAculeata (wasps, hornets, bees, and ants) are ovipositors, highly modified and with associatedvenomglands. 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 stingingHymenoptera, the ovipositor is no longer used for egg-laying. An exception is the familyChrysididae, members of the Hymenoptera, in which species such asChrysis ignita have reduced stinging apparatus and a functional ovipositor.
Fig wasp ovipositors have specialized serrated teeth to penetrate fruits, butgall 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 theDipteran (fly) familiesTephritidae andPyrgotidae 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 speciesCuterebra fontinella has one of the shortest within the family.[5]
Ovipositors exist not only in winged insects, but also inApterygota, 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]
Female bitterlings in the genusRhodeus have an ovipositor in the form of a tubular extension of thegenital orifice. During breeding season, they use it when depositing eggs in the mantle cavity of freshwatermussels, 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.
Themarbled newt, orTriturus 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 breathe during the oviposition process; therefore, the benefit to wrapping the eggs outweigh the cost of holding their breath.[7]
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Media related toOvipositor at Wikimedia Commons
The dictionary definition ofovipositor at Wiktionary