Epiblema minutana (Kearfott, 1905), revised status

(Figs. 2–9, 17–18, 20–23)

Eucosma minutana Kearfott 1905:356; Barnes and McDunnough 1917:170.

Epiblema minutana: Blanchard 1979:179; Miller and Pogue 1984:227.

Eucosma antaxia Meyrick 1920:344, unnecessary replacement name for minutana.

Epiblema strenuana (not Walker): Heinrich 1923:140; McDunnough 1939:48; Powell 1983:35; Miller 1987:56; Brown 2005:286; Gilligan et al. 2008:121; Pohl et al. 2018:151, senior synonym of E. minutana.

Lectotype (designated by Blanchard 1979). ♂, New Jersey, Essex County, Montclair, W. D. Kearfott, July 1908, slide 24505, USNM.

Kearfott (1905) mentioned a series of about 40 specimens from Tryon, North Carolina; Cincinnati, Ohio; New Brighton, Pennsylvania; Plummers Island, Maryland; Belvidere, Illinois; Smith County, Tennessee; Anglesea, New Jersey; and Essex County Park, New Jersey. Klots (1942) stated that Heinrich (1923) had designated a lectotype from Essex County Park, New Jersey but disagreed with Heinrich’s statement that the depository was the AMNH. Blanchard (1979) settled the matter by formally designating the lectotype listed above in the USNM.

Redescription. Epiblema minutana is a dark gray species that lacks any subcostal orange-brown coloration near the apex of the forewing. In size it varies (FWL: 4.3–7.9 mm) much like E. strenuana (FWL: 4.0–9.0 mm) but on average it is somewhat smaller than the latter species (mean FWL = 6.0 vs. 7.1 mm). Previous authors have noted, and we concur, that the forewing is slightly narrower in E. minutana than in E. strenuana (AR = 3.19 vs. 2.80). The interfascial spot is often present as a paler shade of gray (Figs. 5–8), but in some individuals it is barely discernable (Figs. 2–4). The ocellus resembles that of E. strenuana, but the white costal strigulae are usually more prominent than in the latter species.

Epiblema minutana is similar to E. strenuana in genitalia but differs from the latter species in the following respects: the socii (Figs. 17–18) are shorter and sometimes triangular (tapering from a broad base to a narrowly rounded apex vs. consistently fingerlike with parallel lateral margins), and the sterigma (Figs. 20–23) is ovate instead of rectangular, with length-ostium diameter = 1.56 vs. 1.95. Shape of the socii can vary and appear similar to those in E. strenuana. Genitalic characters should be used in combination with wing coloration to make a specieslevel identification.

Remarks. The typical phenotype of E. minutana (Figs. 2–8) is broadly distributed in eastern United States and is also found in central California. In the East, the larval host is presumed to be Ambrosia artimisiifolia L. (annual ragweed), but the adult determinations in literature reports of reared specimens need to be checked for accuracy visà-vis E. strenuana. Epiblema minutana has been reared in Mexico from field-collected larvae from A. confertiflora (McClay 1987) and in Contra Costa County, California, by J. A. Powell from Ambrosia psilostachya DC. (Cuman ragweed), a plant with a transcontinental distribution. The EME has numerous specimens from California with minutana -like genitalia and pale gray forewings (Fig. 9). They are somewhat larger than typical E. minutana (mean FWL = 6.9 vs. 6.0 mm) but are nearly identical in forewing geometry (AR = 3.18 vs. 3.19). This phenotype has been reared from A. psilostachya and from Ambrosia chamissonis (Less.) Greene (silver bur ragweed) (Powell and Opler 2009). The range of the latter plant extends along the Pacific coast from southern California to Alaska. Powell and Opler (2009) reported larvae causing deformities at nodes of lateral decumbent stems but not forming stem galls. Similar specimens are represented in the phylogenetic tree (Fig. 1) from San Diego County, California. These cluster with typical E. minutana but show some minor consistent differences in the sequences that could indicate they are a separate taxon. We can find no morphological differences in these California specimens, thus we tentatively refer them to E. minutana until a more comprehensive DNA analysis can be performed. We can confirm they are not E. strenuana, which is also present in California, and we have examined typical specimens of E. strenuana from the same location in San Diego County.