The
ovipositor is an
organ used by some
animals for
oviposition, i.e. the laying of
eggs. It consists of a maximum of three pairs of appendages formed to transmit the egg, to prepare a place for it, and to place it properly. In some of the
insects the organ is used merely to attach the egg to some surface, but in many
parasitic species (primarily in
wasps and other
Hymenoptera) it is a piercing organ as well. It is used by the
grasshoppers to force a burrow in the earth to receive the eggs and by
cicadas to pierce the
wood of twigs for a similar purpose. Both
long-horned grasshoppers and
sawflies cut the
tissues of
plants by means of the ovipositor. None of these examples is quite as remarkable as the wasp genus
Megarhyssa, the females of which have a slender ovipositor several inches long, used to drill into the wood of
tree trunks. 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 sting of Hymenoptera (wasps, hornets, bees and some ants) is also an ovipositor, in this case highly modified and associated with poison glands (to paralyze the prey so that the eggs can be laid without the host fighting back, and probably also to suppress the host's immune system so that it can't destroy the eggs or shake off the paralysis).[1] In virtually all stinging hymenopterans, the ovipositor is no longer used for egg-laying.
Some Roach-like fish, such as bitterlings, have an ovipositor as a tubular extension of the genital orifice in the breeding season for depositing eggs in the mantle cavity of the pond mussel. Seahorses have an ovipositor serving a similar purpose.
The BBC documentary Walking with Dinosaurs portrayed a Diplodocus mother using an ovipositor to lay her eggs.[2]
