Beneficial Species Profile
Photo credit: Copyright Bruce Marlin, Mike McCarthy
Common Name: Giant Ichneumon Wasp
Scientific Name: Megarhyssa macrurus
Order and Family: Hymenoptera: Ichneumonidae
Size and Appearance: Length (mm) Appearance Egg Tiny and threadlike, deposited on the surface of the living Pigeon Horntail Wasp larvae within decayed wood.
Larva/Nymph Larvae consume their host within the decayed wood. Adult Female body 51mm, ovipositor Head and thorax are red or reddish 100mm brown, abdomen has transverse bands of black and pale yellow Male smaller than female, no stripes. The legs are red. Wings are ovipositor. tan/clear with a triangluar black mark on the leading edge of the forewing near the tip. The antennae are long, slender and black. The ovipositer is very long, filamentous, and black.
Pupa (if applicable) Pupa remains dormant under tree bark and emerges the following summer.
Type of feeder (Chewing, sucking, etc.): Larvae: chewing
Host/s: Pigeon Horntail Wasp
Description of Benefits (predator, parasitoid, pollinator, etc.): The Giant Ichneumon Wasp is a parasitoid of the Pigeon Horntail Wasp larvae, and is associated with several species of dying hardwood trees (silver maple, ash, cottonwood, elm). The female uses her long ovipositor to deposit eggs deep into trees where her larvae will feed on the Pigeon Horntail Wasp larvae.
References: Barlow, V. (2010). Giant Ichneumon Wasp. Northern Woodlands Magazine. http://northernwoodlands.org/articles/article/giant-ichneumon-wasp
Cranshaw, W. (2004). Garden Insects of North America: The Ultimate Guide to Backyard Bugs. Princeton, NJ: Princeton UP. Print.
Cranshaw, W. (2013). Pigeon Tremex Horntail and the Giant Ichneumon Wasp – 5.604. Colorado State University Extension. http://extension.colostate.edu/topic-areas/insects/pigeon- tremex-horntail-and-the-giant-ichneumon-wasp-5-604/
"What Is This Wasp With a 4 Inch Long Thready Tail?" Natural Crooks Ramblings. N.p., n.d. Web. 08 Apr. 2016. http://naturalcrooks.com/rambles/what-is-this-wasp-with-a-4-inch-long-thready- tail/