great black digger wasp - Species Profile
Conservation • Description • Habitat • Ecology • Distribution • Taxonomy
Conservation Status
IUCN Red List
not listed
NatureServe
not listed
Minnesota
not listed
Description
Great black digger wasp, also called simply great black wasp, is a large thread-waisted wasp.
Females are larger than males. Males are ¾″ to 1⅛″ long, averaging about ⅞″ long. Females are 1″ to 1⅜″ long, averaging 1⅛″ long. The body is slender and all black.
The upper plate of the first thoracic segment (pronotum) is short and collar-like. There is a short, rounded lobe on each side of the pronotum that does not reach the plate at the base of the wings (tegula). The longitudinal sutures on the upper thoracic plate of the middle abdominal segment (mesonotum) are absent or indistinct. The lower plate of the middle thoracic segment does not have a forked process.
The abdomen is stalked at the base. The stalk of the abdomen (petiole) has two segments.
The wings are black with a dark blue tint. The anal lobe of the forewing is large.
The last leg segment (tibia) of the middle leg has two spurs at the top. There are no claws at the end of the fifth segment of the front tarsus (foot). The first segment of the hind tarsus is slender.
The body hairs are not branched. The erect hairs on the head and thorax are black. There are appressed hairs on the face, silvery on the male, black on the female.
Size
Total length: ¾″ to 1⅜″
Similar Species
Habitat
Meadows, fields, suburban gardens.
Ecology
Season
July to September
Behavior
This is a solitary wasp. It does not create a communal nest, though it sometimes nests colonially. It is usually found on flowers.
The wings are held folded parallel to the body when nectaring.
The sting of this wasp is painful but does not usually swell.
Life Cycle
The female creates a nest by digging a slanting burrow in soft earth, usually in a protected location. The burrow is divided into several cells. She hunts katydids in the genera Microcentrum and Scudderia, which she paralyzes by stinging in the neck and thorax. She carries the paralyzed prey back to the burrow, placing 2 to 6, usually 3, in each cell. She then lays 3 ⁄16″ to ¼″ long eggs on the underside of the prey. When the larvae hatch they feed on the still living but paralyzed katydids.
Adults emerge in mid-summer the following year. They are seen in flight mostly from July to mid-August, though some are seen as late as early September.
Larva Food/Hosts
Paralyzed katydids
Adult Food
Flower nectar and/or pollen
Distribution
Occurrence
Common
Taxonomy
Order
Hymenoptera (Ants, Bees, Wasps, and Sawflies)
Suborder
Apocrita (Narrow-waisted Wasps, Ants, and Bees)
Infraorder
Aculeata (Ants, Bees, and Stinging Wasps)
Superfamily
Apoidea (Bees and Apoid Wasps)
Family
Sphecidae (Thread-waisted Wasps)
Subfamily
Sphecinae
Tribe
Sphecini
Genus
Sphex
Subgenus
Sphex
Subordinate Taxa
Synonyms
Ammobia pensylvanica
Chlorion pensylvanicum
Sphex pensylvanicus robustisoma
Common Names
great black digger wasp
great black wasp
katydid hunter


















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