Endangered Resources Program Species Information
Slender Clearwing (Hemaris gracilis)

Overview

Species Overview

There is no overview information available for that species.

Status and NHI Documented Occurrences in Wisconsin

The table below provides information about the protected status (State and Federal Status) and the rank (S and G Ranks) for Slender Clearwing (Hemaris gracilis). See the Working List Key for more information about the abbreviations used. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. For invertebrates, dots depict locations from the "Invertebrate Atlas," a database with occurrences of rare and common aquatic and select terrestrial invertebrate species found in Wisconsin and adjacent areas. While the invertebrate atlas is a quality assured database, not all records have been verified. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Summary Information State Status: SC/N Federal Status in Wisconsin: none State Rank: S3 Global Rank: G3G4 Tracked by NHI: Y Species of Greatest Conservation Need: Y

Detailed Information

Identification: A small Sphingid moth with transparent wings except for reddish-brown borders and basal areas. The thorax is olive green dorsally, yellow ventrally and marked with a reddish-brown line beneath the wing base. The abdomen is olive green dorsally and marked with a reddish-brown band across it. Difficult to to accurately verify visually due to rapid flight and likely presence of other similar species. Collect and submit specimen to a specialist for verification. Wingspan 40-45 mm. Length of forewing: 19-21 mm. The basic color of the last instar larva is yellow-green with the head slightly darker than body and the ventral surface dark reddish to purplish brown. The characteristic Sphingid posterior horn is reddish, darkening toward the tip (Williams 1979).

Similar Species: The hummingbird clearwing (Hemaris thysbe) is very similar overall, but is a somewhat larger moth, lacking the reddish-brown line beneath the wing base. The body of the snowberry clearwing (Hemaris diffinis) is marked with yellow to greenish-yellow and black, appearing much like a bumblebee.

Habitat: Jack pine/oak barrens and open trails through northern dry forests.

Nectar Source: Orange and yellow hawkweeds (Hieracium spp.), downy phlox (Phlox pilosa), puccoon (Lithospermum sp.) and blueberry (Vaccinium sp.) flowers.

Host Plant: Uses Blue Ridge blueberry (Vaccinium pallidum) along with high bush blueberry (V. corymbosum) in Massachusetts (Williams 1979). The habitat association in Wisconsin suggests early low blueberry (Vaccinium angustifolium) is the likely host in the state. V. pallidum is a rarely encountered species and listed as Special Concern in Wisconsin.

Associated Species: H. gracilis occurs with the phlox flower moth (Schinia indiana) and the dusted skipper (Atrytonopsis hianna) within their ranges in Wisconsin, but H. gracilis is more widespread, likely occurring throughout northern Wisconsin wherever sufficient habitat exists.

State Distribution: Adams, Bayfield, Burnett, Douglas, Eau Claire, Jackson. Marinette, Menominee and Oneida Counties. A species generally seen in small numbers, but would be expected to be more common in view of the abundance of its likely host plant in Wisconsin.

Global Distribution: Nova Scotia to Florida, west through Michigan and Wisconsin to Manitoba.

Threats: Fire may be detrimental to overwintering pupae at the surface of the ground. Also loss of open habitat and repression of hostplant and adult nectar sources by forest succession.

Phenology: Adults are present from late May through late June.

Life History: Univoltine. Eggs hatch about one week after being deposited. Larval development is completed about four weeks later. Overwinters as a pupa in a loose cocoon in debris at the surface of the ground (Williams 1979). A remnant-dependent species (Panzer et al 1995).

Survey Guidance: Adults are diurnal, active on sunny days and attracted to a variety of nectar sources. Due to its hummingbird-like flight and the difficulty in approaching closely, accurate visual confirmation is very difficult. Adults are not attracted to blacklight at night. New county records should be documented with voucher specimens.

Inventory, Monitoring and Research Needs: Locate additional populations particularly in sites managed with fire. A considerable amount of potential habitat in Wisconsin has not been surveyed. There are likely many undiscovered populations throughout northern and central Wisconsin.

Management Guidance: Sites managed with fire should be divided into several burn units leaving the majority of the site unburned in a given season. Avoid burning adjacent units in successive seasons.

Information originally presented as part of the Online Field Guide to Rare Lepidoptera: Bogs and Barrens.

Photos

Click on a photo to view a larger version. Please considering donating your photos to the Endangered Resources Program for educational uses. See also information regarding use of photos

Photo © Les Ferge.

Related Links

Links to Additional Slender Clearwing Information

• Butterflies and Moths of North America (BAMONA) [Exit DNR]

Other Links Related to Butterflies and Moths

• Wisconsin Butterflies (Mike Reese)
• More Butterfly Links
• The Field Museum [Exit DNR]
• Online Field Guide to Rare Lepidoptera: Bogs and Barrens