Ammophila nigricans

Dahlbom, 1843

thread-waisted wasp

Ammophila nigricans is a large, striking thread-waisted in the , recognized by its deep -black body with red abdominal banding and black . It is one of the largest eastern in its , comparable in size to A. procera but readily distinguished by its coloration. Females are solitary nesters that excavate burrows in clayey or sandy soil and provision them with paralyzed as food for their . The species ranges across the eastern United States from Kansas and Texas to New England and south to Georgia, Florida, and Louisiana. It appears less common than most other Ammophila species.

Ammophila nigricans, f, right, Jorge Blay 2022-02-04-14.28.08 ZS PMax UDR copy (52235600012) by USGS Bee Inventory and Monitoring Lab from Beltsville, Maryland, USA. Used under a Public domain license.

Ammophila nigricans (43535909070) by Melissa McMasters from Memphis, TN, United States. Used under a CC BY 2.0 license.

Ammophila nigricans, Meadowood Farm SRMA, Mason Neck, Virginia by Judy Gallagher. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Ammophila nigricans: //ˌæ.moʊˈfaɪ.lə ˈnaɪ.ɡrɪ.kænz//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Easily distinguished from all other Ammophila by the combination of: (1) lack of silver stripes on the (present in most including A. procera); (2) deep -black body with red abdominal ; (3) entirely black . The similar-sized A. procera has prominent silver thoracic stripes and clear or smoky wings rather than black. A. wrightii and A. formicoides are much smaller, -mimetic, and uniformly reddish-.

Images

Habitat

Open areas with clayey or sandy soil suitable for nest excavation. have been observed nectaring on flowers including mint blossoms and Swamp . The is associated with supporting its .

Distribution

Eastern United States: from Kansas and Texas eastward to New England, and south to Georgia, Florida, and Louisiana. Records include Massachusetts, Ohio, Illinois, Kansas, and throughout the southeastern states.

Seasonality

Active during warm months; observed in July and August. Females may be found at dusk adopting a characteristic sleeping posture, gripping grass stems or twigs with their at approximately a 45-degree angle.

Diet

feed on nectar from various flowers including mint and . are provisioned with paralyzed by the female parent.

Host Associations

Catocala spp. (underwing moths) - / provisioned as food for larvae
Euparthenos nubilis (locust underwing) - / provisioned as food for larvae
Zale spp. (zale moths) - / provisioned as food for larvae

Life Cycle

Solitary nesting . Females excavate vertical or angled burrows in soil, terminating in a horizontal chamber. The nest is provisioned with one or more large paralyzed , upon which a single is laid. The feeds externally on the caterpillar. Detailed developmental timing and number of per year are not well documented.

Behavior

Females are solitary and non-aggressive. They exhibit a distinctive sleeping at dusk, gripping vegetation with their while holding the body at an angle. When hunting, females locate by touch rather than visual cues, as the cryptic typically remain motionless during the day. Females have been observed to provision nests with multiple large caterpillars. The is less frequently encountered than , suggesting either lower abundance or more secretive habits.

Ecological Role

of , particularly large . As a solitary , it contributes to regulation of . The serves as a for , which have been documented in related Ammophila species.

Human Relevance

Not aggressive toward humans; only if handled. Of potential interest for biological study of parental care strategies and - relationships. The has been subject of research into how maternal provisioning influences risk of parasite transmission to offspring.

Similar Taxa

Ammophila proceraSimilar large size, but distinguished by silver thoracic stripes, lack of red abdominal , and non-black
Ammophila wrightiiMuch smaller, -mimetic, uniformly reddish-, with different nesting (burrow excavated after capture)
Ammophila formicoidesMuch smaller, -mimetic, uniformly reddish-, closely related to A. wrightii

More Details

Research significance

Ammophila nigricans has been used in studies of parental care evolution, specifically demonstrating that provisioning nests with multiple small (rather than one large caterpillar) greater risk of transmitting to offspring. This work by RJ Millena and Jay Rosenheim showed that this single behavioral trait explains approximately 90% of variation in risk across Ammophila species.

Taxonomic notes

The was originally described by Dahlbom in 1843. Western and eastern of some related Ammophila species show variation in (number of submarginal ), but this has not been specifically documented for A. nigricans.