Moths of North Carolina
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12 NC Records

Alcathoe caudata (Harris, 1839) - Clematis Clearwing

Alcathoe caudataAlcathoe caudataAlcathoe caudataAlcathoe caudata
Taxonomy
Superfamily:
Sesioidea		 Family:
Sesiidae		Subfamily:
Sesiinae		Tribe:
Synanthedonini		P3 Number:
55a0172		 MONA Number:
2623.00
Comments: Of the 136 or more members of the Sesiidae that occur in North American north of Mexico, 37 have been recorded in North Carolina. Some sesiids, known broadly as clearwing borers, are significant pests of commercial crops. The great majority are mimics of wasps and hornets.
Identification
Field Guide Descriptions: Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Eichlin and Duckworth (1988)Technical Description, Immature Stages: Engelhardt (1925)                                                                                 
Adult Markings: The males of this species are easily identified by the yellowish antenna, the outer third of the hindleg with black, orange and yellow patterning, and the elongated, yellowish tail that extends from the tip of the abdomen. The following detailed description of the male is based on that of Engelhardt (1946) and Eichlin and Duckworth (1988).

The antenna has a mixture of yellowish and brownish-black scales on the basal half that phase into yellow or orangish coloration on the apical half. The labial palp is nearly smooth and deep yellow, while the head is black with an orangish-red collar. The thorax is black and slightly touched with reddish or orangish-red along the sides and on the posterior margin. The abdomen is black above and orange to reddish-brown below, while the anal tuft is black at the base, with a soft, hairy, yellow appendage (‘tail’) that can be as long as or slightly longer than the abdomen. The coxa on the foreleg is mostly orangish-red, while the other coxae and femora are brownish-black. The tibiae are orangish-red with brownish-black at the apical tufts, but mostly yellow on the hind tibia between the blackish spurs. The tarsi are yellow except for the first segment of the hindtarsus, which is orangish-red and tufted laterally. The forewing is opaque and blackish on the apical half and transparent on the basal half, while the underside has orange at the base of the costal margin. The hindwing is entirely transparent with very narrow blackish margins, a small discal spot, and a brownish-black fringe.

The females are generally similar, but the antenna is entirely pale yellow, and the labial palp is yellow beneath and black above. The collar is orange and the anal tuft narrow and black with lateral tufts. The forewings is entirely black and the hindwings is transparent, while the posterior tibia and first tarsal joint are black, and the last tarsal joints yellow. The females of A. caudata are very similar to female A. carolinensis, but those of A. caudata usually have a reddish collar (black in A. carolinensis), palps that are yellowish below (black in A. carolinensis), legs with the tarsi more boldly marked with yellow, a large transparent region on the forewing, and a completely transparent hindwing.

The descriptions above are for the typical forms. A dark color variant known as "walkeri" differs from the normal form in having the labial palps, collar, legs, and anal appendage all black, while the antenna is mostly black above and rufous beneath. This form is rare, but Engelhardt (1946) noted that the typical form and the dark variant were both present in the same population from the Black Mountains in North Carolina. Males of the dark form closely resembles the males of A. carolinensis, with both having a black tail. It is best distinguished by the antenna color, which is mostly yellow, but darker towards the basal half in A. carolinensis, versus solid black in A. caudata, except for a rufous-colored tip that is sometimes present.

Wingspan: Males 22-30 mm; females 23-33 mm (Engelhardt, 1946).
Forewing Length: 7-15 mm (Brown and Mizell, 1993).
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The following life history account is based on that of Engelhardt (1925), who studied this species mostly in New York. The adults in this area emerge in June and July, and the females lay eggs at or near the crown root of the plant. The hatchlings tunnel their way into the main root where they feed near the soil level. The larvae feed for 2-3 months during late-summer or early fall, then overwinter in their tunnels. Feeding resumes with the spring warm-up and the larvae continue feeding through early summer. Tunneling can cause root swelling in small plants, and ugly scars and distorted roots in old plants. Engelhardt (1925) noted that the large plants can house a dozen or more larvae. Pupation occurs within the tunnel in an oblong cocoon that is made of silk and root chips, and the adults emerge shortly thereafter. The life cycle requires about one year.
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Alcathoe caudata is endemic to the eastern US and adjoining areas of southern Canada (Ontario; Quebec; Nova Scotia). The range in the US extends from Maine and other New England states southwestward to northern Florida and westward to Louisiana, western Tennessee, western Kentucky, Iowa, eastern Nebraska, Wisconsin and southeastern Minnesota. This species appears to be absent from the central and southern portions of the Atlantic Coastal Plain. As of 2024, all of our records are from the Piedmont and lower-elevation sites in the Blue Ridge. It has not been found in the Coastal Plain where its host plant is generally absent.
County Map: Clicking on a county returns the records for the species in that county.
Alcathoe caudata
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Flight Comments: The adults have been observed from April through September in different areas of the range, with most flying from June through September. Local populations in North Carolina appear to be univoltine. As of 2024, our records range from with early-June to mid-September.
Habitats and Life History
Habitats: Local populations are strongly reliant on Virginia Virgin's-bower (Clematis virginiana) for successful reproduction, which is commonly found in moist and partly sunny to sunny habitats.
Larval Host Plants: The larvae are borers in Clematis. The primary host appears to be Virginia Virgin's-bower (Clematis virginiana), but the use of other native Clematis is possible (Eichlin & Duckworth, 1988). Reports of this species using Ribes appear to be incorrect. Stephen Dunn has reported damage to Clematis virginiana vines in Orange County after recording two adults on the plant. - View
Observation Methods: The adults are diurnal active and are often seen resting on vegetation or visiting flowers. They are often seen resting on Clematis virginiana. Engelhardt (1925) noted that the adults are easy to rear if the roots of infected plants are harvested when the larvae are pupating.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR [S3S4]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: Alcathoe caudata is found through the Piedmont and Blue Ridge, but is restricted to sites where Clematis virginiana and perhaps other native Clematis are present. Clematis terniflora is an aggressive invasive, and there is some concern that it might be outcompeting C. virginiana since they have similar habitat requirements. It is currently uncertain if any of our two Alcathoe species can use C. terniflora as a host.

 Photo Gallery for Alcathoe caudata - Clematis Clearwing

Photos: 7

Recorded by: J.B. Sullivan on 2023-08-08
Wilkes Co.
Comment: 		Recorded by: Jamie Harrelson on 2023-07-04
McDowell Co.
Comment:
Recorded by: Stephen Dunn on 2022-09-11
Orange Co.
Comment: 		Recorded by: Stephen Dunn on 2022-09-11
Orange Co.
Comment:
Recorded by: Stephen Dunn on 2022-09-11
Orange Co.
Comment: 		Recorded by: Kristin Wyatt on 2021-08-24
Ashe Co.
Comment:
Recorded by: J. Merrill Lynch on 2015-07-30
Watauga Co.
Comment: