Moths of North Carolina
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View PDFSaturniidae Members: 126 NC Records

Anisota stigma (Fabricius, 1775) - Spiny Oakworm Moth


Taxonomy
Superfamily: Bombycoidea Family: SaturniidaeSubfamily: CaratocaminaeP3 Number: 890014.00 MONA Number: 7716.00
Comments: One of four species in this genus that occurs in North Carolina (3 others occur north of Mexico -- Tuskes et al. 1996)
Identification
Field Guide Descriptions: Covell (1984); Beadle and Leckie (2012)Online Photographs: MPG, BugGuide, BAMONATechnical Description, Adults: Forbes (1923), Ferguson (1971), Tuskes et al. (1996)Technical Description, Immature Stages: Forbes (1923), Ferguson (1971), Covell (1984), Tuskes et al. (1996), Wagner (2005)                                                                                 
Adult Markings: Adult males are distinctive. Compared to the males of other species of Anisota, they are unique in possessing opaque reddish wings with dark specklings and a well-defined, if diffuse, postmedian line; they are the only males that fly during the night and that are attracted to lights. Some confusion might be possible with male Sphingicampa bicolor, but the inner margin of the forewing is much shorter than the outer margin in Anisota species, whereas it is nearly equal in length in Sphingicampa (Forbes, 1923). Adult females differ from S. bicolor in this same respect, and the speckling on their forewings is shared among Anisota species only by A. senatoria. Female A. stigma can be distinguished from A. senatoria by the presence of a well-defined medial line on the hindwing and by similar coloration on both sets of wings; in senatoria, the hindwings are typically paler than the forewings. Photographs showing only the forewings may not provide enough information to separate these two species, but female A. stigma tend to be darker colored and possess more extensive speckling; they also are usually larger and have broader wings.
Wingspan: 45 mm, males; 60 mm, females (Forbes, 1923)
Adult ID Requirements: Identifiable from photos showing hindwings, abdomen, or other specialized views [e.g., frons, palps, antennae, undersides].
Immatures and Development: Larvae -- Spiny Oakworms -- like other members of this genus, have two prominent, black thoracic spines. Last instars are easy to recognize by their lack of longitudinal stripes and by the presence of numerous small white tubercles scattered all over the body and horns (Ferguson, 1971; Wagner, 2005).
Larvae ID Requirements: Identifiable from good quality photos, especially where associated with known host plants.
Distribution in North Carolina
Distribution: Probably found throughout the state except at high elevations where oaks are uncommon
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)

Click on graph to enlarge
Immature 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: Single brooded, flying primarily in mid-summer
Habitats and Life History
Habitats: Probably associated with most types of oak forests in the state. The majority of our records come from upland habitats, particularly dry-to-xeric sandhills in the Coastal Plain, where they may feed predominantly on Turkey oak, and monadnocks in the Piedmont (in the Northeast, this species is now more or less restricted to barrens habitats; Wagner, 2005). However, we also have records from lowlands and mesic slopes from across the state, indicating some use of non-xerophytic oaks.
Larval Host Plants: Oligophagous, feeding primarily on oaks, including Northern red oak (Quercus rubra) and Turkey oak (Q. laevis), but also reported on Chinquapin, hazel and basswood (Ferguson, 1971; Wagner, 2005).
Observation Methods: Both sexes come fairly well to blacklights and incandescent lights. Adults do not feed and consequently do not come to bait. Spiny oakworms feed more solitarily than other species of Anisota, are less likely to have outbreak years, and are generally more difficult to find (Tuskes et al., 1996)
Wikipedia
See also Habitat Account for General Oak-Hickory Forests
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: G5 [S5]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands
Comments: Populations are locally vulnerable to the effects of weather, outbreaks of disease, parasites, and predators, and to the effects of pesticides. However, given the commonness of their host plants, wide habitat range -- including suburban areas -- and statewide distribution, this species can easily recover from localized losses. In the Northeast, however, this species has been extirpated from Connecticut and other areas where it once occurred (Wagner, 2012), possibly due to parasitism by a Tachinid fly, Compsilura concinnata, that was widely introduced in the Northeast to control Gypsy Moths and other pest Lepidoptera. This fly represents a serious and pervasive threat for many species of moths and is suspected to be responsible for the marked declines in several Saturniids. While such impacts have not yet been documented in North Carolina, Compsilura has spread as far south as Virginia (Kellogg et al., 2003) and will probably continue to expand its range southward. The situation in North Carolina needs to be monitored.

 Photo Gallery for Anisota stigma - Spiny Oakworm Moth

43 photos are available. Only the most recent 30 are shown.

Recorded by: Jim Petranka and Bo Sullivan on 2021-08-09
Moore Co.
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Recorded by: Jim Petranka and Bo Sullivan on 2021-08-09
Scotland Co.
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Recorded by: Jim Petranka and Becky Elkin on 2021-07-22
Graham Co.
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Recorded by: Jim Petranka on 2021-07-14
Madison Co.
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Recorded by: Jim Petranka on 2021-07-11
Madison Co.
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Recorded by: Jim Petranka on 2021-07-06
Madison Co.
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Recorded by: tom ward on 2021-06-26
Buncombe Co.
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Recorded by: Steve Taylor on 2020-08-01
Beaufort Co.
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Recorded by: Steve Taylor on 2020-08-01
Beaufort Co.
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Recorded by: Kyle Kittelberger, Brian Bockhahn on 2020-07-16
Polk Co.
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Recorded by: Kyle Kittelberger on 2020-07-11
Wake Co.
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Recorded by: Jim Petranka and Becky Elkin on 2020-07-03
Madison Co.
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Recorded by: Owen McConnell on 2020-06-20
Durham Co.
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Recorded by: Gary Maness on 2020-06-20
Guilford Co.
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Recorded by: Gary Maness on 2020-06-20
Guilford Co.
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Recorded by: Simpson Eason on 2019-09-07
Durham Co.
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Recorded by: Ken Kneidel on 2019-06-26
Mecklenburg Co.
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Recorded by: Ken Kneidel on 2019-06-26
Mecklenburg Co.
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Recorded by: Ken Kneidel on 2019-06-26
Mecklenburg Co.
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Recorded by: Vin Stanton on 2018-06-20
Buncombe Co.
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Recorded by: Vin Stanton on 2018-06-20
Buncombe Co.
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Recorded by: Jim Petranka and Becky Elkin on 2018-06-19
Madison Co.
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Recorded by: Jim Petranka and Becky Elkin on 2018-06-19
Madison Co.
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Recorded by: David L. Heavner on 2018-06-13
Buncombe Co.
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Recorded by: Jim Petranka and Becky Elkin on 2018-05-30
Madison Co.
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Recorded by: Lenny Lampel on 2016-07-07
Mecklenburg Co.
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Recorded by: K. Moore on 2015-07-25
Chatham Co.
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Recorded by: B. Bockhahn, P. Scharf, S. Hall on 2015-07-22
Stanly Co.
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Recorded by: Jim Petranka and Becky Elkin on 2014-07-01
Madison Co.
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Recorded by: C. Bowers on 2013-09-25
Cumberland Co.
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