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Journal of the Lepidopterists' Society 57(4), 2003, 270-273
SCLEROCONA ACUTELLA (EVERSMANN) (CRAMBIDAE: PYRAUSTINAE), NATURALIZED ALONG THE EASTERN SEABOARD
David L. Wagner
Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut 06269, USA. E-mail:
david.wagner@uconn.edu
DougC. Ferguson1
Systematics Entomology Laboratory, USDA, Agricultural Research Service, c/o National Museum of Natural History,
Washington, DC 20560-0168, USA
AND
John D. Glaser
6660 Loch Hill Road, Baltimore, Maryland 21239, USA
ABSTRACT Sderocona acutella (Eversmann), a Eurasian species previously undocumented from North America, is reported from 14 localities in Connecticut, Massachusetts, Maryland, and Rhode Island. The first North American specimen was captured in 1984 at a coastal location in Bristol, Massachusetts. Capture and rearing records suggest the moth feeds on common reed, Phragmites australis (Cav.) Trin. ex Steud. (Poaceae), in freshwater and brackish wetlands. Given the increasing abundance of Phragmites along water courses and some upland habitats, Sderocona stands to become one of the regions most common wetland moths.
Additional key words: alien species, Phragmites, biocontrol, wetlands.
Sderocona acutella is a large, easily recognizable, wetland pyraustine. It is native to Europe and Asia, occurring from Spain and Sicily northward to Great Britain (as a stray) and Denmark (rare) east to Siberia, Japan, and China (Inoue et al. 1982, Palm 1986, Karsholt & Razowski 1996, Parent! 2000, Siberian Zoological Museum 2002). Ongoing surveys of Lepi-doptera in southern New England and Maryland revealed the presence of Sderocona in a variety of wetlands along the eastern sea board of the United States, including estuaries, marshes, fens, swamps, and lake and pond margins. We assume that the species was introduced accidentally, but because larvae feed on Phragmites australis (Cav.) Trin. ex Steud. (Poaceae), an aggressively invasive plant in many northeastern wetlands, there remains the possibility that it was purposefully introduced, although we were unable to locate any literature indicating such.
Voucher specimens are deposited in the following institutions and personal collections: John D. Glaser (JGC), Lloyd Center for Environmental Science (LCES), University of Connecticut (UCONN), and University of Rhode Island Biological Control Lab (URI). Selected references and a diagnostic description follow.
Sderocona acutella (Eversmann)
Cramhus acutellus Eversmann, 1842:563.
Sderocona acutella Meyrick, 1890:445. Meyrick proposed Sderocona with Crambus acutellus Eversmann as the only included species.
1 Deceased.
Sclericona acutellus, Marion, 1957:82. Sderocona acutellus, Palm, 1986:231, Sderocona acutella, Karsholt & Razowski (eds.), 1996:194.
Diagnostic description. Length of forewing (males): 11.5-12.5 mm. The light brown adults of this species superficially resemble their namesake, Nascia acutella (Walker) of eastern North America (see Munroe 1976: pi. 1, figs. 67-71), but Sderocona adults have much longer porrect palpi, glossy white wing fringe scales, a pale costa, and lack the distinctive pale intervenular streaks of the forewing of Nascia. The unique forewing venation (Fig. 5) of S. acutella males is probably diagnostic within our fauna. The cubital stem bends deeply into the posterior side of the discal cell and back again, reducing the proximal half of the cell to only half the width of the distal half. This makes space, as it were, for a curiously enlarged and modified, cornucopia-shaped retinaculum (Figs. 3, 4), which opens dis-tally and provides a shelter on the wing surface just inside its opening for a small mat of darker, specialized scales of uncertain function (perhaps the structure and modified scales serve to disperse a sex pheromone).
The male genitalia (Fig. 6) are unlike those of the nearctic Nascia acutella but show surprising similarity to those of Oenobotys Munroe (Crambidae: Pyrausti-nae) (Munroe 1976: pi. A, figs. 6, 7; Ferguson et al. 1991: figs. 203a, c), having a similar fanlike cluster of processes on the inner face of the valve that resemble spatulate scales, each of which is expanded and bi- or trifurcate at its outer end. However, Sderocona acutella also has a separate, prominent, spinose scle-
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Figs. 1-4. Sclerocona acutella. 1, Adult male, dorsal. 2, Adult male, ventral. 3, Retinaculum (arrow). 4, Cleared forewing.
rite (4-5 spines) embedded in the valve beneath (or behind) the fanlike structure as viewed on the slide. The uncus is elongate, smooth, and regularly tapered from base to tip. The aedeagus has almost no sclerotized inclusions (cornuti). The everted vesica shows only one blind sidepocket (diverticulum) at about its midpoint, and a small, low, weakly sclerotized hump farther out.
Distribution. Connecticut: Fairfield Co., Danbury, Tarrywile Park, 8.vi.2001, D. L. Wagner (1) (UCONN); Litchfield Co., Canaan, Robbins Swamp, The Nature Conservancy Hollenbeck Preserve, l/2.vii.l997, M. Volovski (l)(UCONN); Salisbury, Moore Brook, 8/9.vii.l994, D. L. Wagner, V. Giles & M. C. Thomas, MV & blklt (l)(UCONN); same locality, 23-30.vi.1995, D. Wagner, J Trouern-Trend, D. Primozich & M.C. Thomas, MV & blklt (7)(UCONN); Salisbury, Twin Lakes, 8/9.vii.l994, D. L. Wagner, V. Giles & M. C. Thomas, MV & blklt (l)(UCONN); same locality, 14.vii.1995, V Giles
& A. Valley, MV & blklt (l)(UCONN). Massachusetts: Barnstable Co., Bourne, 23.vi-21.vii.1995, M. Mello, blklt trap (3)(LCES); Bristol Co., South Dartmouth, Lloyd Center, 2.vii.l984, M Mello, blklt (1) (LCES); same locality, 26.vi.1989, M Mello, blklt (1) (UCONN); Hampden Co., Brimfield, 14.vi.1996, M Mello, blklt trap (1) (LCES); Hampshire Co., Amherst, 7 May, 1999 (larva), adult issued circa 15 June, 1999, Lisa Tewksbury and Geoffrey Balme (1)(URI); Suffolk Co., Boston, Thompson Island, 24.vi.2002, M Mello, blklt trap (3) (LCES). Maryland: Dorchester Co., Taylor's Island Wildlife Management Area, 14.vi.1998, J.D. Glaser, blklt (4)(JGC, USNM); Harford Co., Bush Wildlife Management Area, 5.vi.l999, J.D. Glaser, blklt (9)(JGC, USNM); Worcester Co., Isle of Wight, l.vi.2000, J.D. Glaser, blacklight traps (26) (JGC, USNM); Hickory Point Cypress Swamp, 29.V.2002, J.Glaser, blklt (1)(JGC). Rhode Island: Newport Co., Tiverton Pocassett Swamp, 25.vi.2001, M Mello, blklt trap (1); Little Compton, 25.vi.2001, M Mello, blklt trap (1)(LCES).
Early stages. Parenti (2000) and Robinson et al. (2002) list Phragmites australis as the host for Sclero-
5
Figs. 5-6. Sclerocona acutella. 5, Wing venation. 6, Male genitalia
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cona acutella. Lisa Tewksbury and Geoffrey Balme (pers. com.) reared a single adult from a larva collected in the lower stem of Phragmites, on May 8-9, 1999, near Amherst, Massachusetts. The Phragmites stem was dead and broken; presumably it had been alive through the fall of the previous season. The single larva is believed to have pupated without further feeding.
Common reed, Phragmites australis, grows in both freshwater and brackish wetlands, which is consistent with the range of localities represented among our collections. Label data suggest the species is univoltine. Records from southern New England, where the species is best known, range froml4 June to 21 July (n = 23), with most collections falling within the last week of June and the first half of July. The Maryland specimens were collected between 1 and 14 June; the four from the latter date being slightly worn, indicating that Sclerocona flies earlier in Maryland.
Distribution in eastern North America. North American records are from both inland and coastal wetlands from Massachusetts, Connecticut, Maryland, and Rhode Island. The first North American specimen is believed to be a male taken by Mark Mello in South Dartmouth, Bristol County, Massachusetts, at the Lloyd Science Center in 1984. Although the moth certainly is distributed more widely, correspondence with other microlepidopterists suggests that it may not have spread much beyond the range we circumscribe here. We have written to (microlepidoptera) collectors in Maine (Tony Roberts), Michigan (George Balogh and Brian Scholtens), Ohio (Steve Passoa), Ontario (Jean-Francois Landry), and Quebec (Louis Hanfield)— none have yet taken this species.
Etymology. The generic name is a compound of the Greek adjective sclero, meaning tough, hard, and the Latin masculine noun, conus (or the Greek konos), obviously referring to the cone-shaped retinaculum. Meyrick (a classics scholar) intended Sclerocona to be feminine, spelling it with a feminine ending and changing the species name from acutellus to the feminine form, acutella. We mention this because some authors have continued to use acutellus in combination with the feminine generic name.
Remarks. Given the broad distribution of the moth along the eastern seaboard and the scant collections of pyraloids, the moth surely has been established for some time on the East Coast. Short of drawing inferences from detailed population genetic studies, there would seem to be no way to establish when, where, or how this species was introduced.
Mikkola and Lafontaine (1994) made the observation that several recently introduced moths in the Northeast, e.g., Apamea unanimis (Lliibner), A. ophio-
t1999 1996 2002 1995 1984, 1989 2001 2001 1997 ____________
Fig. 7. Distribution of Sclerocona acutella along eastern seaboard. Locality data appears in text.
gamma (Esper), and Rhizedra lutosa (Hiibner) are Phragmites, Phalarus, or other grass-feeders that are common in coastal habitats in Europe. The recently established Oligia strigilis (L.) reported by Handfield (1999) also fits this pattern (J. Don Lafontaine pers. com.). Mikkola and Lafontaine (1994) suggest that the turf and soil being picked up in shipyards, e.g., on the bottoms of large shipping containers, could be responsible for the recent spate of European coastal moth introductions along our eastern seaboard. Sclerocona acutella, being a Phragmites feeder, is yet another candidate for their list.
Phragmites australis is the focus of conservation efforts on both sides of the Atlantic Ocean, but for different reasons. In parts of Europe it is a local, protected species that has even been the focus of restoration efforts (e.g., Skuhravy 1978, Ostendorp 1989, Tscharntke 1990, 1992). On this continent, the plant is considered an invasive species that is overrunning wetlands, establishing almost pure monocultures of reed in coastal and inland wetlands that previously were floristically diverse (Garcia 1998, Chambers et al. 1999; Orson 1999, Saltonstall 2002). Given the newfound successes of Phragmites, we expect that adult Sclerocona will be become one of the most abundant moths in the vicinity of wetlands in many northeastern states. If the moth proves to be a specialist of Phragmites, it might have a future as a biocontrol agent in programs seeking to curb the spread of this grass.
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Acknowledgments
Our friend and colleague, Doug Ferguson, passed away on 4 November 2002. He had assembled a partial draft of this paper in 2001. It is with deep sense of loss and admiration for Doug that we complete this small paper. Rene Twarkins prepared the line drawing of the wing venation and helped assemble the figures. Mark Mello sent us data from his numerous collections of Sclerocona. Lisa Tewksbury and Geoffrey Balme supplied observations on their collection and rearing of Sclerocona. Several students, friends, and colleagues helped with the acquisition of the Connecticut specimens: Valerie Giles, Jon Trouern-Trend, Dave Primozich, Michael Thomas, and Monty Volovski. David Grimaldi and Tarn Nguyen took the image of the male genitalic capsule using a Nikon D1X digital camera with an Infinity (c) K2 lens, illuminated with fiber optic flashes from MicrOptics, Inc. We thank Peter Touhey and Alma Solis for recovering host rearing information from a Systematic Entomology Laboratory database and relaying it to us. Steven Passoa helped us track down European and Asian literature. Funding for surveys that resulted in captures of Sclerocona to DLW was provided by the Connecticut Chapter of The Nature Conservancy, Connecticut Department of Environmental Protection, and Connecticut State Museum of Natural History.
Literature Cited
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Received for publication 20 December 2002; revised and accepted 26 April 2003.