Megarhyssa macrurus explained

Megarhyssa macrurus, also known as the long-tailed giant ichneumonid wasp^[1] or long-tailed giant ichneumon wasp,^[2] is a species of large ichneumon wasp.^[3] It is a parasitoid, notable for its extremely long ovipositor which it uses to deposit an egg into a tunnel in dead wood bored by its host, the larva of a similarly large species of horntail.

Etymology

The specific epithet of macrurus is from the Greek words Greek, Modern (1453-);: makrós (Greek, Modern (1453-);: [[:wikt:μακρός|μακρός]]) meaning "long", and Greek, Modern (1453-);: oùrá (Greek, Modern (1453-);: [[:wikt:οὐρά|οὐρά]]) meaning tail.^[4]

Description

Megarhyssa macrurus has a reddish-brown body of up to 2inch long.^[5] It has black and yellow-orange stripes.^[6] Its wings are transparent and the body elongated. The body and ovipositor together can be more than 5inch long in the female. Males are smaller and have no ovipositor.

The ovipositor

The ovipositor looks like a single filament, but it comprises three filaments, the middle one of which is the actual ovipositor, which is capable of drilling into wood. This central filament also appears to be a single filament, but is made of two parts, with a cutting edge at the tip. The two parts interlock and slide against each other.

Although very thin, the ovipositor is a tube and the egg being laid moves down a minute channel in its center. The outer two filaments are sheaths which protect the ovipositor; they arc out to the sides during egg-laying.

Distribution

M. macrurus is found across the eastern half of the United States, reaching into the extreme south of Canada near the Great Lakes.^[7]

Behaviour

M. macrurus is harmless to humans;^[8] they are parasitoids on the larvae of the pigeon horntail (Tremex columba, Symphyta), which bore tunnels in decaying wood.^[9] Female Megarhyssa macrurus are able to detect these larvae through the bark; they paralyse them and lay their eggs on the living but paralysed larva; within a couple of weeks the Megarhyssa larvae will have consumed their host and pupate, emerging as an adult the following summer.

Subspecies

Subspecies include:^{[10] [11]}

• M. m. icterosticta Michener, 1939
• M. m. lunator (Fabricius, 1781) - considered a synonym of M. m. macrurus by Carlson (1979)^{[10] [12]}
• M. m. macrurus (Linnaeus, 1771)

External links

• High quality images of Megarhyssa macrurus
• Videos of Megarhyssa macrurus Ovipositing

Notes and References

1. Web site: Megarhyssa macrurus, Long-tailed Giant Ichneumonid Wasp . Cresswell . Stephen . 2020. American Insects . 2020-06-04.
2. Web site: Long-Tailed Giant Ichneumon Wasp . . MDC Field Guide . Missouri Department of Conservation . 2020-06-04.
3. http://www.insectimages.org/browse/subthumb.cfm?sub=11643 Ichneumonid wasp, Megarhyssa macrurus (Hymenoptera: Ichneumonidae)
4. http://bugguide.net/node/view/84171 Species Megarhyssa macrurus
5. Web site: Giant Ichneumon Wasp: Long-tailed (Megarhyssa macrurus) . 2019 . Insect Identification for the Casual Observer. 2020-06-04.
6. http://extension.colostate.edu/topic-areas/insects/pigeon-tremex-horntail-and-the-giant-ichneumon-wasp-5-604/ Pigeon Tremex Horntail and the Giant Ichneumon Wasp
7. Web site: Megarhyssa macrurus. Discover Life; Global Biodiversity Information Facility. 10 July 2017.
8. Web site: Ichneumon wasp . 2010-12-14 . dead . https://web.archive.org/web/20101210085728/http://insects.tamu.edu/fieldguide/cimg327.html . 2010-12-10 .
9. http://insects.tamu.edu/fieldguide/cimg327.html Ichneumon wasp
10. Pook. Victoria. Sharkey. Michael. Wahl. David. 2016-01-04. Key to the species of Megarhyssa (Hymenoptera, Ichneumonidae, Rhyssinae) in America, north of Mexico. Deutsche Entomologische Zeitschrift. en. 63. 1. 137–148. 10.3897/dez.63.7619. 1860-1324. free.
11. http://essigdb.berkeley.edu/cgi/eme_species_query?query_src=eme_queryspecies&special=browse&rel-ordr=eq&groupby=genus&orderby=genus&selectlist=genus,species,subspecies,author,year,photo,seq_num&rel-family=eq&where-ordr=&where-family=Ichneumonidae&lfile=&where-collection=1 Essig Museum of Entomology Collections
12. Book: Carlson, Robert W. . 1979 . Krombein . Karl V. . Hurd . Paul D. Jr. . Smith . David R. . Burks . B.D. . Catalog of Hymenoptera in America North of Mexico . Smithsonian Institution Press . 354–355 . Family Ichneumonidae . 1 . https://www.biodiversitylibrary.org/page/4144148#page/335/mode/1up.