Megarhyssa nortoni
Encyclopedia
Megarhyssa nortoni is a species of large ichneumon wasp
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of 2 inch to 3 inch in length. The male is less colorful with no ovipositor.
wasp larvae in coniferous trees. The adult female hunts horntail larvae for egg placement. It smells wood-eating fungus, utilized by the horntail larvae to predigest wood pulp, and uses its antennae to detect vibrations made by the horntail larvae. The female Megarhyssa nortoni curls its ovipositor over its abdomen to insert the tip of the ovipositor at a right angle into the bark and cuts into the tree until it reaches the horntail larval tunnel. The female then deposits a very slender egg through its ovipositor into the tunnel on or near the horntail larva. The Megarhyssa nortoni larva then hatches to eat the live horntail larval host from the inside causing the horntail larva's eventual death. The Megarhyssa nortoni larva pupates inside its host and emerges the following summer as an adult.
Although imposing, the female Megarhyssa nortoni does not sting and is harmless to humans. Adult Megarhyssa nortoni feed on nectar and water.
It has also been introduced to New Zealand, Tasmania, and Brazil to help control horntail forest pests.
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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Description
Megarhyssa nortoni is black, reddish brown, and yellow and has distinguishing round yellow spots down the side of the abdomen. Its legs are mostly yellow. Its wings are transparent, and the body is elongated with a length of 1.4 inch. The female is notable for an ovipositorOvipositor
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...
of 2 inch to 3 inch in length. The male is less colorful with no ovipositor.
Behavior
Megarhyssa nortoni is a predatory insect. Its larvae are parasites of horntailHorntail
Horntail or wood wasp is the common name for any of the 100 non-social species of the family Siricidae, of the order Hymenoptera, a type of xylophagous sawfly...
wasp larvae in coniferous trees. The adult female hunts horntail larvae for egg placement. It smells wood-eating fungus, utilized by the horntail larvae to predigest wood pulp, and uses its antennae to detect vibrations made by the horntail larvae. The female Megarhyssa nortoni curls its ovipositor over its abdomen to insert the tip of the ovipositor at a right angle into the bark and cuts into the tree until it reaches the horntail larval tunnel. The female then deposits a very slender egg through its ovipositor into the tunnel on or near the horntail larva. The Megarhyssa nortoni larva then hatches to eat the live horntail larval host from the inside causing the horntail larva's eventual death. The Megarhyssa nortoni larva pupates inside its host and emerges the following summer as an adult.
Although imposing, the female Megarhyssa nortoni does not sting and is harmless to humans. Adult Megarhyssa nortoni feed on nectar and water.
Habitat
This species is found in coniferous forests in Western North America.It has also been introduced to New Zealand, Tasmania, and Brazil to help control horntail forest pests.