Norton's Giant Ichneumonid Wasp
Megarhyssa nortoni
Classification
- Phylum: Arthropoda
- Subphylum: Hexapoda
- Class: Insecta
- Order: Hymenoptera
- Superfamily: Ichneumonoidea
- Family: Ichneumonidae
- Subfamily: Rhyssinae
- Genus: Megarhyssa
- Species: nortoni
Pronunciation
How to pronounce Megarhyssa nortoni: //ˌmɛɡəˈrɪsə ˈnɔrtoʊnaɪ//
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Summary
Megarhyssa nortoni, known as Norton's giant ichneumonid wasp, is a large ichneumon wasp whose larvae are parasitoids of horntail larvae, impacting the control of tree pest populations. It exhibits sexual dimorphism in coloration and ovipositor length and is mainly found in coniferous forests.
Physical Characteristics
Body length 25-38 mm; ovipositor length 50-76 mm. Females mostly have red-and-black abdomens with yellow lateral spots, while males have a black mesoscutum with a single yellow spot on the mesopleuron. Legs are mostly yellow and wings are transparent.
Identification Tips
Females have a longer ovipositor (about 2 times the body length) and distinctive yellow spots on the abdomen. Males are recognized by the black mesoscutum and lack of colorful markings.
Habitat
Coniferous forests where horntail larvae are present.
Distribution
Native to North America, from Newfoundland to northern Georgia, and from Alaska to California. Subspecies include M. nortoni nortoni in the western US and southwestern Canada, and M. nortoni quebecensis in the northeastern US and southeastern Canada. Also introduced in Australia, New Zealand, Brazil, and South Africa.
Diet
Adult M. nortoni feed on nectar and water; larvae are parasitoids of horntail larvae.
Life Cycle
Females locate horntail larvae, lay eggs on or near them, and the larvae develop by feeding on the host from the inside. The larvae pupate inside their host and emerge as adults the following summer.
Reproduction
Females lay eggs on horntail larvae within the tunnels they create in wood.
Ecosystem Role
Natural predator of horntail larvae, helping to control populations of these pests in forest ecosystems.
Economic Impact
Introduced in various countries to aid in the control of horntail forest pests.
Health Concerns
Although large and potentially imposing, females do not sting and are harmless to humans.
Collecting Methods
- Netting
- Trapping
Preservation Methods
- Ethanol
- Pinning
Misconceptions
Despite its size, the female does not sting and poses no threat to humans.
Tags
- Insect
- Hymenoptera
- Parasitoid
- Megarhyssa
- Ichneumonidae
- Invasive Species