Catocala amestris
Three-staff underwing

Key Characteristics

The three-staff underwing is a brightly-colored, medium-sized moth (1.6-1.8 in [4.0-4.5 cm] wingspan). The forewings are pale gray or light gray-brown with strong dark lines and shading. The forewings also have a fairly large kidney-shaped or reniform spot outlined in black. The hindwings are yellow-orange with two wavy, black bands, of which one is located along or near the outer margin and the other is located about halfway into the hindwing. The larvae are bluish white with yellowish coloring on the dorsum (top) and sides, an orange band and and seven thin, lateral black stripes on each side.

Status and Rank

  • State Status: E
  • State Rank: S1
  • Global Rank: G4

Occurrences

County NameNumber of OccurrencesYear Last Observed
Barry11990
Distribution map for Catocala amestris

Updated 1/31/2017. 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.

Habitat

The larvae of the Three-staff underwing feed exclusively on leadplant, Amorpha canescens, a special concern plant that is usually found in small colonies in degraded prairies and rights-of-way in southern Michigan. In other states, larvae of this species have been observed feeding on locust (Robinia), but leadplant is the only known host plant for this species in Michigan. The Three-staff underwing is associated with dry-mesic sand prairies and silt-loam prairies containing populations of leadplant. These habitats in Michigan are currently typically restricted to remnants along railroad and power line right-of-ways. This species also is associated with old field, savanna, upland shrub and dry hardwood habitats.

Specific Habitat Needs

Host plant needed in Oak openings, Oak barrens, Dry-mesic prairie, Dry sand prairie

Natural Community Types

Methodology

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

Habitat loss and degradation have threatened the persistence of this species and its host plant. Much of the prairies, oak barrens and savannas with which this species and its hostplant are associated have been lost, fragmented and/or degraded due to conversion to agricultural lands, residential and commercial development, fire suppression and altered fire regimes and introduction of invasive species. Protection of the only known extant colony of three-staff underwing in the state is critical. Surveys to assess the extent, abundance and status of this population and to find additional populations are needed. Research to obtain additional information on the species' life history and ecology and assess threats to the species also is warranted. Habitat management is a necessity at the extant site as autumn olive has become a problem. Management of this site requires fire or prescribed burning to control vegetative succession, particularly from autumn olive. Prescribed burning can be used as a management tool to try to re-establish or replicate natural fire regimes of these systems. In areas where this species or other rare invertebrates occur or are of management concern, burning strategies should allow for ample refugia (e.g., only burning part of the available habitat at a time, burn frequency and intensity, type of fire, etc.) to minimize incidental take or other potential adverse impacts and facilitate effective post-burn survival and/or recolonization.

Active Period

Flight from third week of June to second week of August

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. Adults of this species also can be surveyed with bait traps (e.g., "sugaring" which consists of baiting moths by painting sugar syrup to trees) .

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed May 27, 2017]

References

Survey References

Technical References

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