Megarhyssa macrurus
Encyclopedia
Megarhyssa macrurus is a species of large ichneumon wasp
Ichneumon wasp
The Ichneumonoidea are insects classified in the hymenopteran suborder Apocrita. The superfamily is made up of the ichneumon wasps and the braconids...

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It is a predatory insect, notable for its extremely long ovipositor
Ovipositor
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...

. It uses this to deposit an egg into the tunnel bored by another species of wasp
Wasp
The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...

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Etymology

Macrurus is from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 words meaning "long", and meaning tail.

Description

Megarhyssa macrurus has a reddish-brown body approximately 2 inch long. It has black and yellow-orange stripes. Its wings are transparent and the body elongated. The female of this species has an ovipositor of approximately 4 inch in length. Males are smaller (and have no ovipositor).

The ovipositor

The ovipositor appears as a single filament, but it comprises three filaments. The middle filament is the actual ovipositor which is capable of drilling into wood. This middle filament looks like a single filament, but is made of two parts. These parts have a cutting edge at the tip. They interlock and slide against each other.

Although very thin, it is a tube and the egg moves down the minute channel in its center during egg laying. Two other thin filaments serve as protection for the ovipositor. They arc out to the sides during egg laying.

Behaviour

Megarhyssa macrurus is considered harmless to humans. Its species are predatory insects. On the trunks of dead trees, they seek out the tunnels created by their natural enemy, another species of wasp, the pigeon tremex horntail (Tremex columba
Tremex columba
The Pigeon tremex, Tremex columba, is a species of horntail, native to Eastern and Western North America. The females are larger than the males, with females growing to 25-30mm in length, and males about 20-25mm. The larvae feed on dead and dying trees such as beech, elm, maple, and oak.Megarhyssa...

). Pigeon horntails are wood-borers. They tunnel into the dead wood, and deposit an egg.

Megarhyssa macrurus seeks out these tunnels. They are able to detect pigeon horntail larva through the bark of the dead or dying tree. When the female finds one, she drills into the wood to reach the larva. After laying her egg next to the larvae of the pigeon horntail, she will sting the larva, paralyzing it. The Megarhyssa macrurus larvae will then completely consume the paralyzed larva within a couple of weeks. It will then pupate and remain under the bark of the wood until the next summer, at which time it will emerge as an adult.

Subspecies

Subspecies include:
  • Megarhyssa macrurus icterosticta, Michener, 1939
  • Megarhyssa macrurus lunator
  • Megarhyssa macrurus macrurus (Linnaeus, 1771)

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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