Diptera - Fruit flies

Strauzia verbesinae Steyskal

Photograph by Gary J. Steck

Kingdom:	Phylum:	Class:	Order:	Family:
Animalia	Arthropoda	Insecta	Diptera	Tephritidae
Animals	Arthropods	Insects	Flies	Fruit flies

SPECIES DESCRIPTION

Size: Approximately 7-8 mm from antennae to tip of wings.
Wing pattern: An intricate pattern of yellow and brown markings, including an F-shaped pattern at the wing tip.
Body color: Mostly orangish throughout with yellow markings on the thorax.
Head: Elongate. Male with two (occasionally four) pairs of prominent, black, enlarged and thickened bristles.
Oviscape: Slightly darker orange than abdomen, with dark brown ring around extreme apex, approximately 0.6-0.9 mm long.

 Photographs:

 Strauzia verbesinae, Adult male, Cades Cove, May 2002, Photograph by Gary J. Steck.

Similar species:

At least five other species of Strauzia are found in GSMNP and all are quite similar having yellow bodies and striped wings, but they can be differentiated using details of the wing pattern and aculeus tip shape. Other yellow-bodied and striped-wing tephritids such as Zonosemata, Trypeta, and some species of Rhagoletis are superficially similar.

DISTRIBUTION:
(GSMNP in green)

Kentucky, Virginia, and Tennessee (GSMNP). Considered rare by Foote et al (1993), but locally "numerous" by Stoltzfus (1988).

 

  In Park:

Locally abundant in western Cades Cove and Sugarlands.

 

 HOST PLANTS:

 Restricted to Verbesina occidentalis (L.) Walter (Asteraceae).

 NATURAL HISTORY

 Habitat:

 Open sunny fields, meadows, and bordering woodlands containing the host; generally at lower elevations. Very common in western Cades Cove but scattered elsewhere in GSMNP.

Phenology

 Univoltine. Adults emerge in late spring and can be found until late summer.

 Breeding and Courtship:

 Observed on or near the host.

 Oviposition and Immature Stages:

Females oviposit into the upper half of the stem. Larvae mine the stem until early fall when pupariation takes place near ground level.

 Predators and Parasites:

 Unknown.

 Community Ecology:

 Other insect infesters of Verbesina occidentalis include the gall making Eutreta rotundipennis as well as stem-mining Lepidoptera. Relationships among them are not known.

 CONSERVATION BIOLOGY:

Populations of this fly depend on maintenance of its host plant populations, which, in turn, require regular disturbances to maintain open meadows and edges along forests and roadsides.

 Special Protection Status:

- Rangewide: None

- In Park: All plants and animals are protected within the Great Smoky Mountains National Park. Collection requires a permit which is usually granted only for research or educational purposes.

ACKNOWLEDGMENTS

 Text:

Gary J. Steck, Ph.D., Florida State Collection of Arthropods, Gainesville
Bruce D. Sutton, Florida State Collection of Arthropods, Gainesville

Photographs:

Gary J. Steck, Ph.D., Florida State Collection of Arthropods, Gainesville

Web Page Development:

Bruce D. Sutton, Florida State Collection of Arthropods, Gainesville

REFERENCES

Foote, R. H., F. L. Blanc, and A. L. Norrbom. 1993. Handbook of the fruit flies (Diptera: Tephritidae) of America north of Mexico. Cornell University Press, Ithaca, New York, 571 pp.
Steck, G. J. and B. D. Sutton. 2000. New records for Tephritidae (Diptera: Tephritidae) in Great Smoky Mountains National Park. Insecta Mundi 14: 256.
Steyskal, G.C. 1986. Taxonomy of the adults of the genus Strauzia Robineau-Desvoidy (Diptera, Tephritidae). Insecta Mundi 1: 101-117.
Stoltzfus, W.B. 1988. The taxonomy and biology of Strauzia (Diptera: Tephritidae). Journal Iowa Academy Science 95: 117-126.

GLOSSARY

aculeus - the needle-like ovipositor, or egg-laying structure, of female tephritid flies.
oviposition - The act of laying eggs.
oviscape - The hardened sheath enclosing the aculeus.
puparium - The hardened, cocoon-like structure, unique to Diptera, which develops from the cast 3rd instar skin, within which metamorphosis from pupa to adult takes place.
univoltine - Having one generation per year.

Last Updated: October 24, 2002