Plants and Animals

Eucosma giganteana Giant eucosma moth

species photo
James Adams

Key Characteristics

This small moth is in the family Tortricidae with a wingspan of 3.4 to 3.8 cm. The size is highly variable, but color, maculation, and genitalia are constant.

Status and Rank

US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: GNR - Not ranked
State Rank: SNR - Not ranked


CountyNumber of OccurrencesYear Last Observed

Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


The giant eucosma moth is a root-borer found where its host plants, cup plant (Silphium perfoliatum) and prairie dock (S. terebinthinaceum), grows (Heinrich 1923; Heppner 2003; Metzler et al. 2005). It has been reared on prairie dock (Metzler et al. 2005).

Natural Community Types

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Management Recommendations

Little is known about the status, life history and ecology of this species. Lack of scientific knowledge about this species is an obvious threat. Because so little is known about this species, specific management recommendations cannot be provided at this time. Sites where this species is found to be extant should be protected and managed appropriately including maintaining healthy, viable populations of the host plants. Surveys to document populations and determine the status, abundance and distribution of this species in the state are needed.

Survey Methods

The best way to survey for this species is by blacklighting, a technique where a sheet is stretched across two trees or poles and an ultraviolet light is used to attract moths to the sheet. Moths can be collected directly from the sheet. Insects come to light usually in largest numbers on still, dark, cloudy nights when both temperature and humidity are high. This species is difficult to identify in the wild. It is strongly recommended that observations of this species be verified through actual specimen vouchers or verification by a species expert.


Survey References

  • Covell, Charles. A Field Guide to the Moths of Eastern North America. Peterson Field Guide Series, Houghton Mifflin Company, Boston, MA. 496 pp.
  • Martin, J.E.H. 1977. The Insects and Arachnids of Canada (Part 1): Collecting, preparing, and preserving insects, mites, and spiders. Publication 1643. Biosystematics Research Institute, Ottawa.

Technical References

  • Heinrich, C. 1923. Revision of the North American moths of the subfamily Eucosminae of the family Olethreutidae. United States National Museum Bulletin 123:1-298.
  • Heppner, J.B. 2003. Arthropods of Florida and Neighboring Land Areas: Lepidoptera of Florida. Florida Department of Agriculture 17(1): 1-670.
  • Metzler, E.H., J. A. Shuey, L.A. Ferge, R.A. Henderson, and P.Z. Goldstein. 2005. Contributions to the Understanding of Tallgrass Prairie-Dependent Butterflies and Moths (Lepidoptera) and their Biogeography in the United States. Bulletin of The Ohio Biological Survey, New Series 15. No. 1. 143pp.
  • Riley, C.V. 1881. Transactions of the Academy of Science of St. Louis 4:316-324.