Epiblema strenuana ( Walker, 1863 )

Gilligan, Todd M., Wright, Donald J., Brown, Richard L., Augustinus, Benno A. & Schaffner, Urs, 2020, Taxonomic issues related to biological control prospects for the ragweed borer Epiblema strenuana (Lepidoptera: Tortricidae), Zootaxa 4729 (3), pp. 347-358 : 352-354

Epiblema strenuana ( Walker, 1863)

( Figs. 10–16 , 19, 24–26 )

Grapholita strenuana Walker 1863:383 .

Grapholita exvagana Walker 1863:383 .

Steganoptycha flavocellana Clemens 1865:238 .

Grapholita subversana Zeller 1875:318 .

Paedisca strenuana: Walsingham 1879:52 ; Fernald 1882:40; Walsingham 1884:140.

Eucosma strenuana: Fernald 1903:458 ; Barnes and McDunnough 1917:170.

Epiblema strenuana: Heinrich 1923:140 , figs. 257, 258; McDunnough 1939:48; Darlington 1947:95; Miller 1972:214; Powell 1983:35; Miller and Pogue 1984:227; Miller 1987:56; Brown 2005:286; Gilligan et al. 2008:121; Horak 2008:310; Powell and Opler 2009:135; Pohl et al. 2018:151.

Types. Grapholita strenuana . Lectotype (designated by Miller and Pogue 1984) ( Fig. 10 ). ♂, North America , Carter Collection, BMNH (E) 819923, slide 5737, BMNH. Grapholita exvagana . Lectotype (designated by Miller and Pogue 1984). North America , Carter Collection, BMNH (E) 819924, BMNH [hindwings and abdomen missing]. Steganoptycha flavocellana . Lectotype (designated by Darlington 1947). ♂, Type No. 7214, ANSP [abdomen miss- ing]. Grapholita subversana . Syntypes? Texas, Boll , MCZ [ Brown 2005 lists these types as lost] .

Both G. strenuana and G. exvagana seem to have been described from specimens with a moderately wellexpressed white interfascial spot; Miller and Pogue (1984) designated the same specimens that N. S. Obraztsov provisionally selected as lectotypes. The number of specimens supporting the description of S. flavocellana is unknown. Darlington (1947) attributed the lectotype designation to Heinrich (1923), but Heinrich did not provide enough information to designate a single specimen. Miller’s (1973) image of S. flavocellana shows the interfascial spot to be obsolete. Zeller (1875) mentioned three or five syntypes in his description: “ Texas (Boll). Massachusetts at Beverly (Burgess) where two ♀ on 27 June and 3 July were caught. One ♂, one ♀ in Museum Cambridge, one ♀ in my collection.” Regardless of the exact number, Miller and Hodges (1990) did not report any types in the MCZ and Brown (2005) listed the types as lost. All of the above synonymies date to Fernald (1882).

Redescription. Epiblema strenuana is a brownish to grayish species of variable size (FWL: 4.0–9.0 mm, mean = 7.1) and average forewing geometry (AR = 2.80). The interfascial spot, which extends from the inner margin to the radius, varies from whitish ( Figs. 10, 15–16 ) to shades of bronze or gray ( Figs. 11–14 ), in the latter case being weakly distinguishable from the subbasal and median fasciae by its lack of white-tipped scales. Its proximal margin is often indicated by a thin line of pale scales (e.g., Fig. 14 ). The ocellus is white and conspicuous, with a central black longitudinal dash, a black mark on the costal margin, a narrow gray band on the proximal margin, and a black line along the basal edge of the gray band, the last often fragmented into two or three segments. The paired costal strigulae on the distal one-half of the wing are white to gray, usually inconspicuous (except for strigula 9), with associated gray striae extending toward the termen, the last usually separated by lines of orange-brown scales. The specimen in Fig. 16 is representative of a few specimens from southern California that have unusually well expressed costal strigulae.

The male genitalia ( Fig. 19 ) are distinguished by long fingerlike socii, whose lateral margins are nearly parallel. In females, the sterigma ( Figs. 24–26 ) is rectangular and elongate (length about 2 times ostium diameter), the posterior margin of sternum 7 is semicircular and diverges laterally from the sterigma, and the ductus bursae has a twist-like sclerotized contortion near the juncture with the ductus seminalis.

Remarks. Heinrich (1923) stated that the larva is a stem borer on Ambrosia artimisiifolia L. (annual ragweed) without providing the source of that information. Stegmaier (1971) reported rearing Florida specimens from larvae feeding in fusiform galls in the lateral branches of A. artimisiifolia . He also reported rearing a similar but unknown species of Epiblema , later determined by Miller and Pogue (1984) as E. minutana , from larvae boring in stems of A. artimisiifolia . Other larval hosts have been mentioned in the literature, including Parthenium hysterophorus L. (Santa Maria feverfew) ( McClay 1987), Xanthium (cocklebur) ( Miller 1987; Powell and Opler 2009), and Chenopodium (goosefoot) ( Miller 1987), but these records need to be verified. Epiblema strenuana has been used as a biological control agent for a variety of invasive weeds; those species are listed elsewhere in this paper.

This species is broadly distributed over the North American continent. We suspect the distribution of the moth mimics that of its hosts, Ambrosia spp. Xanthium spp., and P. hysterophorus ( Hilgendorf and Goeden 1983; Mc- Clay 1987). Of course, many of the literature records are uncertain due to the long-standing confusion regarding E. strenuana and E. minutana . We examined specimens from 14 states in the region extending from Minnesota to Texas, west to Colorado and New Mexico, east to Maryland and Florida, and several specimens from southern California. In the Midwest, E. strenuana has two primary flights, one in late June, and the other from mid-August to mid-September.

Figures

FIGURES 2–16. Adults. 2–9, E. minutana (2, New Jersey, lectotype; 3, Mississippi, DJW8714; 4, California, DJW8655; 5, Kentucky, TONAB101-09; 6, Ohio, USNM152255; 7, Ohio, DJW8712; 8, Florida, DJW8739; 9, California, DJW8666). 10–16, E. strenuana (10, North America, lectotype; 11, Alabama, DJW8703; 12, Texas, DJW8667; 13, Ohio, USNM152288; 14, Alabama, DJW8704; 15, New Mexico, USNM152289; 16, California, DJW8683).

FIGURES 17–26. Genitalia. 17–18, E. minutana (17, Ohio, TMG782; 18, Ohio, USNM152256). 19, E. strenuana (Iowa, USNM152286). 20–23, E. minutana (20, Kentucky, TMG781; 21, New Mexico, USNM152260; 22, Kansas, USNM152258; 23, Israel, TMG784). 24–26, E. strenuana (24, TMG778; 25, Kansas, USNM152287; 26, Ohio, USNM152288).