Moths of North Carolina
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15 NC Records

Ostrinia penitalis (Grote, 1876) - American Lotus Borer Moth

Superfamily: Pyraloidea Family: CrambidaeSubfamily: PyraustinaeTribe: PyraustiniP3 Number: 801420.00 MONA Number: 4946.00
Comments: This genus was recently revised by Yang et al. (2021), with fifteen species now described worldwide. Four species occur in North America and all occur in North Carolina. As described by Yang et al. (2021), Ostrinia penitalis is included in their Clade II, the Penitalis Species Group.
Field Guide Descriptions: Online Photographs: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Forbes (1923); Munroe (1976)Technical Description, Immature Stages: Center et al. (2002)                                                                                 
Adult Markings: This is a medium-small moth with a pale yellow to yellowish-brown ground color on the forewing. The wing markings and dusting are reddish brown, and both the antemedian and postmedian lines are dentate. The postmedial line extends inward from the inner margin a short distance before bluntly projecting outwards as a large tooth, then projecting inward to form a V-shape. From there, it continues to the costa as an outwardly bowed line with smaller teeth. The subterminal line consists of a diffuse dentate or zig-zag line that is sometimes reduced to a diffuse shaded region. The reniform is represented as a dark line or bar that runs nearly perpendicular to the costa; it is often followed by dark shading. The hindwing is much paler and has a short discal bar or spot in the middle of the wing that is followed by an even but dentate postmedial line that runs fairly straight across the wing, at least as far as the cell. A similarly even, dentate subterminal line is also present.

Ostrinia obumbratalis is similar in size and pattern but has brownish rather than reddish markings. In addition, the short discal bar or spot in the middle of the wing that is present in O. penitalis is missing (Scholtens, 2017). Ostrinia nubilalis is also similar, but is brighter yellow and the face has two clear white lines on the sides of the front instead of straw yellow found in the other species (Forbes, 1923). Crocidophora pustuliferalis is also similar to Ostrinia penitalis, but the latter has a well-developed antemedial line and lacks a line of black dots on the termen. The males also lack a fovea.
Wingspan: 25 mm (Forbes, 1923)
Adult Structural Features: Heinrich (1919) has illustrations of the male and female genitalia.
Adult ID Requirements: Identifiable from photos showing hindwings, abdomen, or other specialized views [e.g., frons, palps, antennae, undersides].
Immatures and Development: The following life history summary is based on Center et al.’s (2002) description when using the primary host, American Lotus (Nelumbo lutea). The females deposit egg masses with around 60 eggs on the upper surface of the lotus leaves. The hatchlings skeletonize the outer surface of the leaf and the young larvae anchor themselves to the leaf with silk threads that functions to reduce being dislodged by wind or wave action. They later feed on the surface within a depression beneath a silk net that serves as a protective shelter. Larvae that feed near the periphery of the leaf often roll the edge over to produce a shelter.

After the larvae reach a length of about 14 mm, they tunnel in the petiole and create a burrow that is usually less than 7 cm long. The burrow primarily serves as a refuge, with the larva feeding on the upper leaf surface within the zone that it can reach from its burrow. This causes radial scars that can be seen on the leaf surface adjacent to the leaf-petiole junction. Heavy feeding by the larvae can cause the leaves to turn brown and deteriorate and cause significant damage to lotus beds. The larvae also feed on developing seed heads and can impart significant losses to the developing seeds.

Larvae that occupy petiole burrows tend to be territorial and may physically defend the burrows against intruding larvae. Intruders will sometimes displace the resident larva and occupy its burrow. The larvae are excellent swimmers and displaced individuals can readily swim to nearby leaves or developing seed heads. Pupation takes place within the petiole. Prior to molting, the larva caps the burrow with a silken plug, then spins a strong cocoon and molts into the pupal stage. Occasionally, an intruder larva will chew through the plug, enter the burrow, destroy the upper end of the resident pupa, and occupy the burrow.
Distribution in North Carolina
Distribution: Ostrinia penitalis is widely distributed across the U.S. where it occurs in the Pacific Northwest, California, and the eastern U.S. It also occurs across much of southern Canada from British Columbia eastward to Quebec, and on several Carribean islands. In the eastern U.S., the range extends from New Hampshire and Connecticut southward to southern Florida, and westward to central Texas, central Oklahoma, Nebraska, South Dakota and eastern North Dakota. A few scattered records are also known from Colorado and Wyoming. As of 2023, we have records from all three physiographic provinces, with most from the northern half of the state.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ‚Č• 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 nearly year-round in Florida and mostly from April through September elsewhere. As of 2023, our records extend from mid-April to mid-September.
Habitats and Life History
Habitats: Our records include several sites where ponds, canals, or sluggish waters are known to be present.
Larval Host Plants: American Lotus (Nelumbo lutea) appears to be the primary host. Ostrinia obumbratalis is a closely related species that feeds on smartweeds and other plants. It was synonymized with O. penitalis in the past (the two are now treated as separate species), and this has been a source of confusion with regard to the actual hosts that are used by O. penitalis. - View
Observation Methods: The adults are attracted to lights.
See also Habitat Account for General Cattail and Tall Grass Marshes
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.

 Photo Gallery for Ostrinia penitalis - American Lotus Borer Moth

Photos: 10

Recorded by: Mark Basinger on 2024-04-09
Wilson Co.
Recorded by: David George, Jeff Niznik on 2023-09-20
Durham Co.
Recorded by: Dean Furbish and Joy Wiggins on 2022-08-14
Wake Co.
Recorded by: Dean Furbish and Joy Wiggins on 2022-08-14
Wake Co.
Recorded by: David George on 2021-08-17
Durham Co.
Recorded by: L. M. Carlson on 2019-08-12
Orange Co.
Recorded by: Paul Scharf on 2015-08-12
Warren Co.
Recorded by: T. DeSantis on 2012-08-07
Camden Co.
Recorded by: Doug Blatny / Jackie Nelson on 2011-05-24
Ashe Co.
Recorded by: T. DeSantis on 2010-07-02
Camden Co.