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".
Identification
Very large blue-black Ichneumon with orange antennae. See images and comments there. Frequents flowers, presumably seeking nectar (?). Several other ichneumonids have this same general pattern (Eric Eaton--comments under various photos).
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.
Range
Widespread eastern United States into Canada (QC. west to MB, south to FL, s. LA., TX, & NM)
(2)Habitat
Fields with flowers, also forests
Food
Adults take nectar, apparently.
Life Cycle
Parasitiod on Sphingid Lepidoptera larvae, especially those found on grapes, Vitis.
Remarks
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:
Other Ichneumons:
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).
(3)
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.
(4)
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.
