Moths of North Carolina
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47 NC Records

Saucrobotys futilalis (Lederer, 1863) - Dogbane Saucrobotys Moth


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Taxonomy
Superfamily: Pyraloidea Family: CrambidaeSubfamily: PyraustinaeTribe: PyraustiniP3 Number: 801407.00 MONA Number: 4936.00
Comments: Munroe (1976) recognized two subspecies, with North Carolina specimens belonging to Saucrobotys f. futilalis
Identification
Field Guide Descriptions: Beadle and Leckie (2012)Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Munroe (1976)Technical Description, Immature Stages: Allyson (1981)                                                                                 
Adult Markings: In this species the head, thorax, antennae, and forewing ground color are concolorous and vary from brownish fuscous to orangish brown. The transverse antemedial and postmedial lines are both dentate and dark brown, with the postmedial outwardly curved on the costal half, then slanting obliquely inward to the inner margin. The hindwing is whitish buff and sometimes narrowly infuscated at the outer margin. The postmedial line is faint and often not evident.
Wingspan: 14-16 mm (Powell and Opler, 2009).
Adult Structural Features: Munroe (1976) has images of the male genitalia.
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae are social and feed on dogbanes (Apocynum spp.) that contain cardiac glycosides and are toxic to birds and mammals. One of the primary defenses of the older larvae is to regurgitate toxic gut contents when attacked by a predator (Grant, 2006). Females lay as many as 150 eggs per clutch on the underside of leaves in a fish-scale like configuration (Grant, 2005). The larvae feed on leaves and live together in a conspicuous nest that is made of leaves that are webbed together. The first two instars are a cryptic green color and feed between webbed leaves. Because of size and food constraints, they ultimately abandon the leaf shelters and feed in the open within the nest for the remainder of the larval period. Correlated with this is a progressive change of the body from green to becoming orange with black spots, a phenomenon that appears to reflect a change in selection from crypsis to aposematism in the later instars (Grant, 2007). The final instar builds a loose outer cocoon with a slightly tighter inner cocoon (BugGuide).
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Saucrobotys futilalis is a very wide-ranging species that occurs across most of the U.S. and adjoining areas in southern Canada, where it occurs from British Columbia to Labrador and Nova Scotia. The range in the U.S. extends from the New England states southward to Florida, and westward to California and the Pacific Northwest. In North Carolina, this species is local common in the Piedmont where the host plant is present and far less common in the Blue Ridge. It appears to be rare in the Coastal Plain where we have only two site records as of 2023.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

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