Fawn Brown Dart

Euxoa pleuritica (Grote, 1876)

Fawn Brown Dart Jim Vargo

Fawn Brown Dart
Jim Vargo

Class
Insecta (Insects)
Family
Noctuidae (Owlet Moths)
State Protection
Not Listed
Not listed or protected by New York State.
Federal Protection
Not Listed
State Conservation Status Rank
S2S3
Imperiled or Vulnerable in New York - Very vulnerable, or vulnerable, to disappearing from New York, due to rarity or other factors; typically 6 to 80 populations or locations in New York, few individuals, restricted range, few remaining acres (or miles of stream), and/or recent and widespread declines. More information is needed to assign either S2 or S3.
Global Conservation Status Rank
G4
Apparently Secure globally - Uncommon in the world but not rare; usually widespread, but may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors.
Contents
  1. Summary
  2. Conservation and Management
  3. Habitat
  4. Range
  5. Identification Comments
  6. Taxonomy
  7. Additional Resources
  8. About This Guide

Summary

Did you know?

Many noctuines that have one generation per year and that occupy habitats that are particularly dry during the summer (for example, grasslands and dunes), such as the fawn brown dart, fly in the late summer or fall (Wagner et al. 2008).

State Ranking Justification

Five populations of the fawn brown dart have been documented in New York State since 1987. The species has a very limited distribution in the East, although it is much more common westward. In New York State, it is expected to occur on Long Island, along the Great Lakes, and in sandy areas in the Adirondacks. Additional surveys are needed to better understand its status and distribution.

Short-term Trends

The short-term trend for the fawn brown dart may be declining. At one site that was surveyed in 1993 and 2005, one individual was captured in 1993, but no individuals were captured in 2005. The other four documented populations have been surveyed only once.

Long-term Trends

The long-term trend for the fawn brown dart may be declining. There are historical records of the species from Orient, Riverhead and "northern New York." Surveys should be conducted to determine if populations are still present in these areas.

Conservation and Management

Threats

Elimination and fragmentation of habitat by commercial and residential development are threats to the fawn brown dart. In addition, fire suppression and allowing succession may eliminate some suitable habitat for the species in the Dwarf Pine Barrens. The species is also vulnerable to mosquito spraying.

Conservation Strategies and Management Practices

Periodic controlled burns or mechanical management are needed to maintain the natural community at the Dwarf Pine Barrens. Since the fawn brown dart is likely to be impacted by extensive fires, it would be beneficial to leave some areas unburned to serve as refugia. Also, since the Fawn Brown Dart is vulnerable to mosquito spraying, it would be beneficial to restrict or minimize mosquito spraying in occupied areas. In addition, restricting ATV use and minimizing lighting to maintain dark sky conditions in occupied areas would be beneficial.

Research Needs

Additional research is needed to document the fawn brown dart's host (larval food) plants and its life history.

Habitat

Habitat

The fawn brown dart inhabits dunes and other sparsely vegetated sandy areas such as pine barrens. In New York State, it has been found in several habitats including maritime grasslands, Great Lakes dunes, dwarf pine plains, and maritime heathlands.

Associated Ecological Communities

  • Dwarf pine plains (guide)
    A woodland community dominated by dwarf individuals of pitch pine and scrub oak that occurs on nearly level outwash sand and gravel plains in eastern Long Island. The soils are infertile, coarse textured sands that are excessively well-drained.
  • Great Lakes dunes (guide)
    A community dominated by grasses and shrubs that occurs on active and stabilized sand dunes along the shores of the Great Lakes. Unstable dunes are sparsely vegetated, whereas the vegetation of stable dunes is more dense, and can eventually become forested.
  • Maritime dunes (guide)
    A community dominated by grasses and low shrubs that occurs on active and stabilized dunes along the Atlantic coast. The composition and structure of the vegetation is variable depending on stability of the dunes, amounts of sand deposition and erosion, and distance from the ocean.
  • Maritime grassland (guide)
    A grassland community that occurs on rolling outwash plains of the glaciated portion of the Atlantic coastal plain, near the ocean and within the influence of offshore winds and salt spray.
  • Maritime heathland (guide)
    A dwarf shrubland community that occurs on rolling outwash plains and moraine of the glaciated portion of the Atlantic coastal plain, near the ocean and within the influence of onshore winds and salt spray.

Range

New York State Distribution

The fawn brown dart is documented from Long Island and Jefferson County. It is expected to occur on Long Island, along the Great Lakes, and in sandy areas in the Adirondacks.

Global Distribution

The fawn brown dart is widespread across the northern states and southern Canada, from Massachusetts in the east to the interior of British Columbia in the west, south to New Mexico and Arizona (Anweiler 2003).

Best Places to See

  • Napeague State Park (Suffolk County)

Identification Comments

Identifying Characteristics

The fawn brown dart is a mottled, copper-brown moth. The forewings consist of mottled pale copper, dark grey, and darker brown areas. The wingspan is approximately 34-38 mm. The small, round orbicular spot is pale with a dark middle; the spot is conspicuous against the dark background. Most, but not all, of the reniform spot has a pale outline. Males have dirty white or light cream hind wings that are darker along the veins and outer margin. Females have darker hind wings than males. Characteristics of male genitalia include that the right harpe is half the length of the right saccular extension, and the left saccular extension is 0.9 times shorter than the right extension. Characteristics of female genitalia include that the ovipositor lobes are rounded at the tip and have fine hairs (Anweiler 2003). A key is provided in Lafontaine (1987).

Characters Most Useful for Identification

The forewing coloration and genitalia characteristics are useful for identification (Anweiler 2003).

Best Life Stage for Proper Identification

The adult is the best stage for identification.

Behavior

Little is known about the life history of the fawn brown dart. There is one generation each year. Larvae overwinter, and mature caterpillars are present from late spring into the summer (Anweiler 2003; Wagner et al. 2008).

Diet

It is thought that the larvae feed on a variety of low-growing plants (Wagner et al. 2008).

Best Time to See

The best time to see the fawn brown dart is during its flight season. In New York State, it has been captured flying from mid-August until early September.

  • Present
  • Reproducing

The time of year you would expect to find Fawn Brown Dart present and reproducing in New York.

Fawn Brown Dart Images

Taxonomy

Fawn Brown Dart
Euxoa pleuritica (Grote, 1876)

  • Kingdom Animalia
    • Phylum Arthropoda (Mandibulates)
      • Class Insecta (Insects)
        • Order Lepidoptera (Butterflies, Skippers, and Moths)
          • Family Noctuidae (Owlet Moths)

Additional Resources

References

Anweiler, G.G. 2003. Euxoa pleuritica. University of Alberta E.H. Strickland Entomological Museum. Online. Available: <http://www.entomology.ualberta.ca/searching_species_details.php?s=4250>

Forbes, William T. M. 1954. Lepidoptera of New York and neighboring states part III. Cornell University Experiment Station Memoir 329.

Hardwick, D. 1970. The Genus Euxoa (Lepidoptera: Noctuidae) in North America. Subgenera Orosagrotis, Longivesica, Chorizagrotis, Pleonectopoda, and Crassivessica. Memoirs of the Entomological Society of Canada. Volume 37.

Lafontaine, J. D. 1987. Noctuoidea, Noctuidae (Part): Fascicle 27.2: Noctuinae (Part-Euxoa). The Moths of America North of Mexico (Lepidoptera). E. W. Classey Ltd. and R. B. D. Publications, London, England. 237 pp.

NatureServe. 2010. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Data last updated August 2010)

New York Natural Heritage Program. 2023. New York Natural Heritage Program Databases. Albany, NY.

North American Moth Photographers Group at the Mississippi Entomological Museum. No date. Mississippi State University, Mississippi. http://mothphotographersgroup.msstate.edu/MainMenu.shtml

Opler, Paul A., Kelly Lotts, and Thomas Naberhaus, coordinators. 2010. Butterflies and Moths of North America. Bozeman, MT: Big Sky Institute. <http://www.butterfliesandmoths.org/> (accessed May 2010).

Wagner, D. L., D. F. Schweitzer, J. B. Sullivan, and R. C. Reardon. 2008. Owlet Caterpillars of Eastern North America (Lepidoptera: Noctudiae)

Links

About This Guide

This guide was authored by: Andrea Chaloux

Information for this guide was last updated on: February 10, 2012

Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Euxoa pleuritica. Available from: https://guides.nynhp.org/fawn-brown-dart/. Accessed December 3, 2023.