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Species Gnamptopelta obsidianator

Black Ichneumon Wasp - Gnamptopelta obsidianator - male Wasp - Gnamptopelta obsidianator Gnamptopelta obsidianator? - Gnamptopelta obsidianator Gnamptopelta obsidianator? - Gnamptopelta obsidianator - female Great Black Wasp ? - Gnamptopelta obsidianator Obsidian Wasp - Gnamptopelta obsidianator Gnamptopelta obsidianator or Ichneumon centrator? - Gnamptopelta obsidianator - male Gnamptopelta? Ichneumon? - Gnamptopelta obsidianator
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Hymenoptera (Ants, Bees, Wasps and Sawflies)
No Taxon ("Parasitica" - Parasitoid Wasps)
Superfamily Ichneumonoidea (Braconid and Ichneumonid Wasps)
Family Ichneumonidae (Ichneumonid Wasps)
Subfamily Ichneumoninae
Tribe Ichneumonini
No Taxon (Callajoppa Genus Group)
Genus Gnamptopelta
Species obsidianator (Gnamptopelta obsidianator)
Other Common Names
Bent-shielded besieger wasp
Synonyms and other taxonomic changes
Gnamptopelta obsidianator (Brulle, 1846)
Explanation of Names
Species name likely from Latin obsidere, meaning to watch over, to besiege, to be on the lookout for. (Latin Dictionary). Suffix -nator indicates "one who", so this is the "Bent-shielded (Gnamptopelta) besieger".
Circa 30-40 mm
Very large blue-black Ichneumon with orange antennae. Abdomen crescent-shaped, flattened, and strongly bent downward. Frequents flowers, presumably seeking nectar (?). Several other ichneumonids have this same general pattern (Eric Eaton--comments under various photos). Eric Eaton was kind enough to ask the opinion of Bob Carlson of the USDA-SEL, who provided the identification--see photos in guide.

These large ichneumons resemble spider wasps (Pompilidae) with their beautiful blue-black coloration and prominent orange marks. They are likely mimics of such wasps as Entypus and Pepsis menechma:

All have orange antennae. Presumably the spider wasp has a wicked sting, but not the ichneumon.
Widespread eastern United States into Canada
Fields with flowers, also forests
Late spring-summer, into early fall in North Carolina. Brimley, p. 403, lists Trogus obsidinator for May, June, Trogus austrinus for May. (1) Guide photos for North Carolina are later in the season.
Adults take nectar, apparently.
Life Cycle
Parasitiod on Sphingid Lepidoptera larvae, especially those found on grapes, Vitis.
Note that identification of species in this family is exceptionally difficult, if not impossible, from photographs, except in a few cases. Note the comments under each photo listed under this species here.
See Also
Spider wasps: Pepsis menechma, Entypus.

-no local photo-
Conocalama brullei is a closely-allied species that is essentially identical in coloration. Genus-level differences include the structure of the petiole (with a conical elevation at the base in Conocalama; absent in Gnamptopelta) and structure of the scutellum (only slightly elevated in Conocalama; distinctly conical in Gnamptopelta).(2)

Ichneumon centrator males are similarly colored but differ in terms of the short, non-conical scutellum and smoother, non-beaded structure of the abdomen.

Thyreodon atricolor is a similarly-colored ophionine species that was frequently confused with Gnamptopelta obsidianator in the early years of BugGuide. This species differs in subfamily-level traits including the distinct lateral compression of the abdomen not found in the ichneumonines. The abdomen also has a distinct "knob" at the end of the petiolus.
Print References
Brimley, p. 403, lists Trogus obsidinator, T. austrinus for North Carolina. These are now apparently considered subspecies. (1)
Sime, K. R., and D. B. Wahl. 1998. Taxonomy, mature larva and observations on the biology of Gnamptopelta obsidianator (Brullé) (Hymenoptera: Ichneumonidae, Ichneumoninae). J. Hym. Res. 7(2): 157-164.
Internet References
List of Ichneumonidae from Gainesville, Florida. This gives information on hosts.
Works Cited
1.Insects of North Carolina
C.S. Brimley. 1938. North Carolina Department of Agriculture.
2.Synopsis of Nearctic Ichneumoninae Stenopneusticae with Particular Reference to the Northeastern Region (Hymenoptera). Part I...
Heinrich G. 1960. Canad. Ent. Suppl., 15:1-87. (Accompanied Vol. 92.).