Diptera - Fruit flies

Rhagoletis pomonella (Walsh)

Photograph by Rebecca P. Shiflett

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

 The Apple Maggot.

SPECIES DESCRIPTION

Size: Approximately 5-7 mm from antennae to tip of wings.
Wing pattern: Four bold black bands that mimic jumping spider silhouette when held in resting position.
Body color: Black except for white scutellum and three or four silvery bands on abdomen.
Oviscape: Black, about 0.6 mm long in ventral view, but appearing only about half that long in dorsal view, weakly tapered to truncate tip.

 Photographs:

 Rhagoletis pomonella, Adult male, The Purchase, August 2002, Photograph by Rebecca P. Shiflett.

Similar species:

At least five other species of Rhagoletis occur in GSMNP. Rhagoletis pomonella is difficult or impossible to differentiate from other species of the pomonella complex (e.g., cornivora, mendax, "Cornus florida") except by host preference. Rhagoletis cingulata and R. suavis have clearly different wing patterns.

DISTRIBUTION:
(GSMNP in green)

Widespread throughout the U. S.

 

 In Park:

The Purchase. Likely to be distributed throughout GSMNP wherever old homesites with apple trees occur, and possibly with other native hosts such as hawthorns or plums (Crataegus and Prunus species).

 

 HOST PLANTS:

 Cultivated apple (Malus). May also be attacking various species of Crateagus or Prunus. 

Cultivated apple
The Purchase, August 2002
Photograph by Gary J. Steck

 NATURAL HISTORY

The natural history of Rhagoletis pomonella and the taxonomy of the pomonella group have been studied in great detail over the past 40 years (see Smith & Bush 2000, Prokopy and Papaj 2000). The evolutionary biology of the group is of great interest as it relates to questions of host race formation and sympatric speciation. Rhagoletis pomonella is native to eastern N. America where it has many natural hosts, notably hawthorns (Crataegus spp). In 1865 a biotype appeared in the Hudson River valley of New York that was highly damaging to cultivated apples introduced from Europe. This pest has spread widely since then.

 Habitat:

 Old fields and homesites where apple trees still exist.

Phenology

Univoltine in northern states but possibly bi- or multivoltine in southeastern states where spring-fruiting Crataegus species occur. Adults have been collected only in August in GSMNP.

 Breeding and Courtship:

 Courtship occurs on or near the host.

 Oviposition and Immature Stages:

 Females oviposit into ripe fruit where larval development occurs. Larvae leave the fruit to pupariate and overwinter in the soil. Pupae may diapause for several years. Immature stages were described by Phillips (1946).

 Predators and Parasites:

 Unknown in GSMNP. Hymenopteran egg and larval parasites are known from other areas. Fly populations that have shifted into new host plants apparently have escaped many of their natural enemies that use host plants as cues. The apparent mimicry of the black wing pattern to jumping spiders has been shown experimentally to be effective in deterring spiders. (See Prokopy and Papaj 2000.)

 Community Ecology:

 Unknown in GSMNP.

 CONSERVATION BIOLOGY:

Rhagoletis pomonella populations may thrive in domestic, agricultural, or natural ecosystems.

 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:

Rebecca P. Shiflett, Knoxville, TN
Gary J. Steck, Ph.D., Florida State Collection of Arthropods, Gainesville

Web Page Development:

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

 REFERENCES

Berlocher, S.H. and M. Enquist. 1993. Distribution and host plants of the apple maggot fly, Rhagoletis pomonella (Diptera: Tephritidae) in Texas. Journal of the Kansas Entomological Society 66: 51-59.
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.
Phillips, V. T. 1946. The biology and identification of trypetid larvae (Diptera: Tephritidae). American Entomol. Soc., Mem. No. 12, 161 pp + XVI plates.
Prokopy, R.J. and D.R. Papaj. 2000. Behavior of flies of the genera Rhagoletis, Zonosemata, and Carpomya (Trypetinae: Carpomyina), pp. 219-252. In Aluja, M. and A. L. Norrbom, eds., Fruit Flies (Tephritidae): Phylogeny and Evolution of Behavior. CRC Press, Boca Raton, Florida, 944 pp.
Smith, J. J. and G.L. Bush. 2000. Phylogeny of the subtribe Carpomyina (Trypetinae), emphasizing relationships of the genus Rhagoletis, pp. 187-217. In Aluja, M. and A. L. Norrbom, eds., Fruit Flies (Tephritidae): Phylogeny and Evolution of Behavior. CRC Press, Boca Raton, Florida, 944 pp.  

GLOSSARY

diapause - a period during which development is delayed, e.g., for overwintering.
oviposition - The act of laying eggs.
oviscape - The hardened sheath enclosing the needle-like ovipositor, or egg-laying structure, of female tephritid flies.
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.
scutellum - The terminal portion of the thorax, usually hemispherical in shape and set apart by a suture.
univoltine - Having one generation per year.

Last Updated: October 23, 2002