Moths of North Carolina
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Donacaula Members:
4 NC Records

Donacaula dispersellus (Robinson, 1870) - No Common Name

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Taxonomy
Superfamily: Pyraloidea Family: CrambidaeSubfamily: SchoenobiinaeP3 Number: 80a1285 MONA Number: 5316.10
Comments: Members of the genus Donacaulis are found worldwide, but reach their greatest diversity in the Nearctic region. The group has proven to be taxonomically challenging due to the fact that most of the species are sexually dimorphic, are very similar externally, and exhibit substantial variation within species. Genitalia have proven to be the most useful diagnostic characters for delineating species, but almost all of the species were originally described based on external coloration and patterning. Descriptions and illustrations of genitalia were also lacking for most species until Martinez (2010) undertook a major revision of the Nearctic species. Her work revealed that there were at least 10 undescribed species in addition to the 11 described species in the New World. Additional studies of DNA barcoding and genitalia, including for North Carolina material, indicate that additional undescribed species remain to be formally described. "Some of these are probably identifiable, but, even with the Martinez thesis, there is a great deal of variation, and especially sexual dimorphism that makes these difficult" (Scholtens, 2017).
Identification
Field Guide Descriptions: Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Adults: Martinez (2010).                                                                                 
Adult Markings: The following is based on the description by Martinez (2010). In the males, the frons, antennae, labial palps and thorax are pale-yellow, while the forewing ground color is yellowish-white and irrorated with brown. The costal margin is tinged with brown scales from the base to all the way to the apex in some specimens, but often fades out before then. There is a brown spot at the apex of the discal cell, and a brown oblique line that runs from the apex towards the outer two-thirds of the inner margin, but fades out before reaching it near the middle of the wing. A line of terminal spots is present along the outer margin.

The female forewing varies from yellow to yellowish-white, and the area between the costa and the discal cell has a prominent longitudinal brown streak from the base to the apex that is often intermixed with yellow or yellowish white scales. There is a brown, oblique line that extends from the apex towards the outer two-thirds of the inner margin that fades near the middle of the wing. A brown spot is present on the apex of the discal cell, and small terminal spots are present along the outer margin between the veins. The hindwing of both sexes is yellowish-white to white, with some specimens slightly irrorated with brown scales. The abdomen has a mixture of yellow and yellowish-white scales, and the anal tuft of the female is yellowish-white. Martinez (2010) noted that most females differ from males in having a longitudinal band below the costa and more intense yellow color, although some females are similar to males in lacking the longitudinal band and having a yellowish-gray color.
Adult Structural Features: Martinez (2010) has descriptions and illustrations of the male and female genitalia.
Adult ID Requirements: Identifiable only by close inspection of structural features or by DNA analysis.
Immatures and Development: Frohne (1939b) provided a detailed life history account of Schoenobius melinellus dispersellus in Michigan, but due to taxonomic confusion, it is uncertain if this study applies to D. dispersellus or D. melinellus, since both species occur in Michigan and require genitalia for identification. We provide a summary of Frohne's (1939b) study below that was mostly conducted at Douglas Lake, with the caveat that it might apply to D. melinellus rather than D. dispersellus, or possibly even to both species.

The larvae at this site primarily feed on a spike rush (Eleocharis palustris). Most adults emerged from mid-July through mid-August. Mating occurred at night and females most commonly deposited clusters of eggs on the upper side of bent-over culm-tops that were near the water surface. Embryonic development to hatching required around 12 days in captivity, and the first instars entered the spike rush culms below water and bored downwards spirally for about a centimeter. With time, they produced 4-7 cm long galleries and grew to 3-4 mm in length. The larvae then migrated by crawling to new plants, which they entered either just below water level or nearer the base. Generally the new galleries, like the old, extended downward, but those larvae which entered stems at their bases begin boring upwards. The older larvae overwintered within the base of culms or culm stubs, then became active again with the advent of warmer weather. In Douglas Lake, larvae resumed feeding during the latter half of June on tender new growth. They moved to new culms frequently, and in some instances the larger larvae severed sections of culms that were just large enough to contain themselves. These silk-lined cases floated at the surface and allowed the larvae to disperse widely. Pupation occurred in a translucent, white cocoon that was about 3.0 cm long. The cocoon was spun within a chamber in the culm and below the lake surface, but falling water levels often expose it. The adults first began emerging around mid-July.
Distribution in North Carolina
Distribution: Donacaula dispersellus is widely distributed across southern Canada (Alberta eastward to Nova Scotia and Prince Edward Island) and in the eastern and central U.S. where it occurs from Maine and Vermont southward to Florida, and westward to Texas, Oklahoma, Kansas, Nebraska, and Illinois. Isolates are also found in Arizona and Colorado (Martinez, 2010; Pohl et al., 2018). As of 2024, all of our records are from the Coastal Plain, including the Sandhills and coastal communities farther east.
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
Flight Comments: The adults mostly fly from June through August in northern and central populations, with a longer flight period in the southern part of the range (April through November; Martinez, 2010). As of 2024, our three dated records are all from the month of May.
Habitats and Life History
Habitats: Our few records are mostly from mesic habitats with seeps or larger wetlands.
Larval Host Plants: Eiseman (2024) reports that larvae feed primarily on spikerushes (Eleocharis), and to a lesser extent sedges (Carex) and bulrushes (Schoenoplectus). - View
Observation Methods: The adults are attracted to lights.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR [S2-S3]
State Protection:
Comments: This species appears to be uncommon within the state, but additional information is needed on its distribution, abundance, preferred habitats and host plants before we can accurately assess its conservation status in North Carolina.