Moths of North Carolina
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185 NC Records

Fissicrambus mutabilis (Clemens, 1860) - Changeable Grass-veneer

Fissicrambus mutabilisFissicrambus mutabilisFissicrambus mutabilisFissicrambus mutabilis
Taxonomy
Superfamily:
Pyraloidea		 Family:
Crambidae		Subfamily:
Crambinae		Tribe:
Crambini		P3 Number:
80a1492		 MONA Number:
5435.00
Species Status: This species is usually seen in a head down position, with the palps resting on the substrate and the rear of the body and wings elevated.
Identification
Field Guide Descriptions: Beadle and Leckie (2012)Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Fernald (1896); Forbes (1923).                                                                                 
Adult Markings: This is a rather nondescript species. The palps and head are gray and the thorax grayish-brown. The ground color of the forewing is variable, but commonly is ashy-gray, grayish-brown or reddish-gray and is speckled with widely scattered dark spots and short streaks. The costa and subcostal region usually has a dark brown wash that extends from the wing base before fading out near the middle of the wing. A diffuse, faint, broad grayish band is often evident that extends from the base and may spread over the costal area except where the dark brown wash is present on the basal half. A relatively large, dark brown to blackish spot (sometimes represented as a pair of dashes) is present near the center of the wing at around two-thirds its length. In the best marked of our specimens, it appears to be a part of a faint jagged median line that is usually obscure. A dentate subterminal line is also present, but also often obscure, and there is a terminal line of seven blackish dots (Fernald, 1896; Forbes, 1923). The fringe is concolorous with the adjoining ground color, and the hindwing is gray or pale fuscous with a slightly paler fringe.
Wingspan: 23-24 mm (Fernald, 1896); 18-24 mm (Ainslie, 1923b).
Adult Structural Features: Ainslie (1923b, 1924) has a description and illustrations of the male genitalia.
Structural photos
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: Ainslie (1923b) studied this species in Tennessee where local populations have two generations and a partial third, with the late-season larvae overwintering. The following life history account is based on his rearing observations in the lab, where larvae were reared on Kentucky Bluegrass, along with his catch of adults outdoors. The females fly shortly after dark and the males between midnight and 3 AM. Females lay several hundred dry eggs either while fluttering over host plants or resting on them. The eggs are cream-colored when fresh, but turn pale salmon yellow within three days. They typically take 5-7 days to hatch during the summer, and the larvae have seven instars.

When feeding on Kentucky Bluegrass the hatchlings first feed by scraping the surface to make small pits on the upper leaf blade. They spin a loose silk webbing above these and add frass. The first three instars skeletonize the leaf blade beneath webbing as just described and leave the lower epidermis intact. They then move to the ground and make a silk-lined burrow with the opening close to the grass stem. The later instar larvae feed above ground and either eat the leaves on the stalk beginning at the base, or cut the grass blades and haul them to their burrows to consume one at a time. Frass is packed into the back of the burrow or into side pockets, and the larvae abandon their burrows and construct new ones as the burrows fill with frass. In late September, the fifth instars construct overwintering, tubular nests made of silk and dried plant material. The nests have the upper end open, and are either suspended from the grass leaves or partially buried in the ground. In Tennessee, the larvae begin feeding again in April and the adults begin to emerge in mid-May. The later instars have a dusky yellow head with groups of rounded dark spots, a brownish body with darker pinacula, and four longitudinal pale or greenish stripes that run down the body. Pupation occurs in a cocoon that is either constructed in an active burrow or in the soil nearby. The cocoon is around 15 mm long and shaped like a peanut seed. It is tightly lined with silk on the inside and covered with soil on the outside. The period from egg to adult emergence in reared animals averaged 55 days (range = 42-70 days), which was consistent with data from trapped adults in the wild.
Distribution in North Carolina
Distribution: Fissicrambus mutabilis is widely distributed across much on the central and eastern U.S. and adjoining portions of southern Canada from Saskatchewan and Manitoba eastward to Nova Scotia and Prince Edward Island. In the U.S. the range extends from Maine southward to southern Florida and westward to central Texas, central Oklahoma, eastern Kansas, eastern Nebraska, Minnesota and northeastern North Dakota. There are isolated records from Colorado and Wyoming. This species occurs statewide in North Carolina.
County Map: Clicking on a county returns the records for the species in that county.
Fissicrambus mutabilis
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 are active year-round in Florida and mostly from June through September in the northern part of the range. As of 2023, our records range from early-April through late-December, with Coastal Plain populations occasionally active through late-December. Local populations appear to have two or three generations per year depending on the locality. Ainslie (1924) noted that there are three generations in Tennessee.
Habitats and Life History
Habitats: Most of our records come from residential neighborhoods, where lawn grasses and ornamental grasses are the likely host plants. Other records come from pastures, meadows and other open habitats. We also have records from forested habitats in fragmented landscapes. Ainslie (1923b) noted that the adults in Tennessee prefer areas with tall grasses such as meadows. They generally tended to avoid both heavily cropped pastures and lawns that are mowed close to the ground. However, they can cause significant damage to lawns that are cut higher from the ground.
Larval Host Plants: The larval hosts include a large number of grass species, including cultivated grains such as corn, oats, barley, rye and wheat, and turf grasses of various sorts (Ainslie, 1923b; Pass, 1965; Robinson et al., 2010; Rogers, 2014). In addition to cultivated grains, the reported hosts include Orchard Grass (Dactylis glomerata), Hairy Crabgrass (Digitaria sanguinalis), Tall Fescue (Lolium arundinaceum), Common Timothy (Phleum pratense) and Kentucky Bluegrass (Poa pratensis). Other grasses are undoubtedly used. - View
Observation Methods: The adults are attracted to UV and building lights, and the larvae can be found in turf grasses.
Wikipedia
See also Habitat Account for General Successional and Semi-Natural Grasslands
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR S4S5
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species is common and widespread within the state and is secure.

 Photo Gallery for Fissicrambus mutabilis - Changeable Grass-veneer

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

Recorded by: David George on 2025-05-16
Durham Co.
Comment: 		Recorded by: John Petranka, Jim Petranka and Becky Elkin on 2025-05-08
Harnett Co.
Comment:
Recorded by: Simpson Eason on 2025-04-19
Brunswick Co.
Comment: 		Recorded by: Mark Basinger on 2025-04-18
Brunswick Co.
Comment:
Recorded by: Mark Basinger on 2025-04-18
Brunswick Co.
Comment: 		Recorded by: Stephen Dunn on 2024-09-04
Orange Co.
Comment:
Recorded by: Jim Petranka on 2024-09-02
Madison Co.
Comment: 		Recorded by: John Petranka on 2024-08-22
Orange Co.
Comment:
Recorded by: Mark Basinger on 2024-08-20
Wilson Co.
Comment: 		Recorded by: Jim Petranka on 2024-08-19
Madison Co.
Comment:
Recorded by: David George, Jeff Niznik, Kenneth Geisert, David Bradley, Julie Tuttle, Patrick Coin, Kaitlyn Elliott, Becky Watkins on 2024-08-17
Durham Co.
Comment: 		Recorded by: Jeff Niznik on 2024-08-12
Orange Co.
Comment:
Recorded by: Jim Petranka on 2024-08-08
Madison Co.
Comment: 		Recorded by: John Petranka on 2024-07-31
Orange Co.
Comment:
Recorded by: Jim Petranka on 2024-07-23
Madison Co.
Comment: 		Recorded by: Jim Petranka on 2024-07-22
Madison Co.
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Recorded by: Ken Kneidel on 2024-07-03
Mecklenburg Co.
Comment: 		Recorded by: John Petranka on 2024-06-20
Watauga Co.
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Recorded by: Emily Stanley on 2024-06-11
Buncombe Co.
Comment: 		Recorded by: Regina Patton on 2024-05-31
Jackson Co.
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Recorded by: Jim Petranka on 2024-05-20
Madison Co.
Comment: 		Recorded by: Stephen Dunn on 2024-05-20
Orange Co.
Comment:
Recorded by: Mark Basinger on 2024-05-12
Rowan Co.
Comment: 		Recorded by: Jeff Niznik on 2024-05-09
Orange Co.
Comment:
Recorded by: Simpson Eason on 2024-05-07
Durham Co.
Comment: 		Recorded by: Mark Basinger on 2024-05-07
Wilson Co.
Comment:
Recorded by: Jim Petranka on 2023-09-10
Madison Co.
Comment: 		Recorded by: David George, Jeff Niznik on 2023-09-04
Orange Co.
Comment:
Recorded by: Mark Basinger on 2023-08-30
Wilson Co.
Comment: 		Recorded by: Mark Basinger on 2023-08-30
Wilson Co.
Comment: