Filatima revisensis Harrison

Harrison, Terry L. & Berenbaum, May R., 2013, A new, prairie-restricted species of Filatima Busck (Lepidoptera: Gelechiidae) from Illinois, Zootaxa 3734 (4), pp. 469-476 : 470-473

Filatima revisensis Harrison , new species

( Figs. 1–5 )

Diagnosis. The three species of the ornatifimbriella color group for which life histories are known can be differentiated by their respective larval host plants (all Fabaceae ): Amorpha canescens (F. re v i s e n s i s), Amorpha fruticosa ( F. ornatifimbriella ), and species in Thermopsis R. Brown , Lupinus Linnaeus , Robinia Linnaeus , and Vicia Linnaeus ( F. xanthuris ). Males of F. revisensis are readily differentiated from those of other species of the ornatifimbriella color group (except F. occidua , the male of which is unknown) by the presence of three separate projections (single costal lobe, plus two projections of saccular lobe) on each valva. In F. ornatifimbriella , F. xanthuris , and F. adamsi , one or both valvae bear only two projections (single costal and saccular lobes). Females of F. revisensis are differentiated from those of other species of the ornatifimbriella color group (except F. adamsi , the female of which is unknown) by the presence of a signum (signum absent in F. xanthuris ), the large, complex signum (signum a small, simple crescent-shaped sclerite in F. ornatifimbriella ), and the presence of an invaginated pocket at the base of each of the anterior apophyses (pockets absent in F. occidua ). Additionally, adult F. revisensis and F. occidua differ in their respective geographic distributions (Midwestern USA versus Washington and California, USA), coloration (brown versus gray), and size (FW length 6.1–8.0 mm, versus 5.5–6.2 mm), and F. revisensis and F. adamsi differ in their respective geographic distributions (Midwestern USA versus Maine, USA).

Description. Adult ( Fig. 1 ). Head. Ocellus present; each scale of vertex and frons pale brown basally, dark brown apically (vestiture of such scales referred to hereafter as "bicolored brown"); haustellum brown basally, then paler brown for most of its length; maxillary palpus brown; labial palpus bicolored brown, mixed with paleochreous scales, the latter predominating on ventromedial surface; second segment with "furrowed brush" scale tuft as typical for genus. Thorax. Dorsum and tegulae bicolored brown; ventral surface shining pale ochreous with a few brown scales. Legs. Lateral surface gray intermixed with pale ochreous, tibia with pale-ochreous band at midlength and apex, medial surface shining pale ochreous, all tarsomeres except fifth with pale-ochreous ring at apex; hind tarsus margined dorsally from near base with a row of long yellowish hairlike scales, inception of row marked by a pale-ochreous blotch on dorsolateral surface of tibia. Forewing. Mean length, 7.1 mm (range, 6.1–8.0 mm, n=6); dorsal surface uniformly bicolored brown, in some individuals with rather extensive suffusion of gray; four dark-brown spots, located as follows: single spot (faint in some individuals) immediately posterior to fold at 0.25 wing length; two spots, separated by fold, at 0.40 wing length, posterior spot located slightly more basally than anterior one; single spot midway between anterior and posterior margins of wing at 0.60 wing length; costal margin gray interspersed with pale-ochreous scales, apical margin to tornus gray but lacking pale-ochreous scales; fringe gray, basal tier of scales dark tipped, forming a line; ventral surface uniformly shining grayish brown. Hindwing. Dorsally and ventrally, wing shining pale brown, not appreciably darkened apically; fringe shining pale brown. Abdomen. Anterior three tergites yellow, remaining tergites brown with shining-gray posterior margins, color change between yellow and brown segments coincident with a change in scale morphology ( Fig. 2 ); venter whitish, heavily intermixed with brown scales. Male eighth abdominal segment modified ( Fig. 3 A-B), the sternite 0.7x as long as wide, with short anterolateral arms, posterior margin rounded and shallowly and narrowly emarginate medially, the tergite 1.6x as long as wide, with elongate anterolateral arms, posterior margin rounded to a broad medial point. Male genitalia ( Fig. 4 ). Uncus and gnathos typical for the genus, the former hoodlike, the latter short, narrow, and hooklike, its posterior margin serrate; vinculum asymmetrical, saccus directed toward left, laterally extending anterodorsad on either side to form a curved projection that attaches to a short projection of the tegumen at its anteroventral extremity; valvae with costal lobes similar, each lightly sclerotized, elongate and narrow, with slightly dilated apex clothed ventrally with a brush of recurved setae; saccular lobes asymmetrical, each divided into an elongate, narrow anteroventral projection and a short, broad medial projection; anteroventral and medial projections of left valva heavily sclerotized, the former longer and slightly broader than anteroventral projection of right valva, the latter nozzle shaped, shorter and broader than medial projection of right valva, and with subapical thornlike development on posterior margin; valva with a projection arising near the base of the costal lobe and extending anterad to attach to the ventral margin of tegumen at a point slightly posterad of the attachment point of the lateral process of the vinculum; phallus massive (as typical for genus), approximately as long as tegumen, 2.8x as long as wide; a narrow sclerotized band runs diagonally from right to left, from 0.2 to 0.5 length of phallus from base; left margin of phallus sclerotized from about 0.3 length to apex, with a keel-like projection at about midlength of phallus; apex of sclerotized margin truncate; central region of phallus bearing three sclerites, two of them (one smaller, the other larger) flat and irregularly curved, the third domelike with a large, heavily sclerotized thornlike projection; a smaller repetition of this latter sclerite occurs at the apex. Female genitalia ( Fig. 5 ). Ovipositor elongate (length approximately 6x width), posterior apophyses 3.6x as long as anterior apophyses; sternite at base of each anterior apophysis invaginated into a large pocket, its surface bearing microspines; ductus bursae membranous, with many microspines, overlain ventrally by a large, sclerotized plate that narrows as it proceeds anterad so as to assume a roughly triangular shape, the ductus being firmly affixed to the plate at its anterior end; at about half its length and slightly to the right of the midline, the plate bears a small, curved finlike projection that appears in ventral aspect as a small dark crescent; corpus bursae and appendix bursae membranous, broadly connected, both large and bulbous; signum large and strongly sclerotized, appearing as curved band with a short, broad thornlike extension at either end and a pair of long, narrow subapical spikes extending at right angles to the band. Larva ( Fig. 3 C). Length of mature larva approximately 11 mm. Coloration typical of larvae of this genus: head and prothoracic shield orange, body whitish with paired dorsal, subdorsal, and lateral blackish stripes.

Biology. Larva on Amorpha canescens . A row of opposing leaflets (often an entire leaf) is silked together to form a feeding chamber; late-stage feeding damage is characterized by browning of the affected leaflets. Pupation occurs either inside the larval shelter or (usually) outside the shelter in a frass-covered silken cocoon. Bivoltine, overwintering as mature larva. Pupation of overwintered larvae occurs in central Illinois probably in early May, as first-generation adults are seen in mid- to late May. Second-generation larvae mature and pupate in mid-June; adults emerge, mate, and oviposit in early July; second-generation larvae, which will overwinter, mature in early to mid-August.

Distribution. Presently known from tallgrass prairies in Mason, Menard, and Morgan Counties in Illinois; also collected in Allamakee County in Iowa (MJ Hatfield, in litt., larvae on leadplant) and in Swift and Chippewa Counties in Minnesota (R. Dana; specimens examined by T. Harrison). The actual range may be substantially larger, considering that leadplant occurs across a wide section of central North America, including two Canadian provinces and 19 states in the USA (USDA, NRCS 2012). However, F. revisensis appears to be local in occurrence; for example, in our survey, it was absent from a high-quality prairie in Jersey County, Illinois (approximately 160 km south of the sites mentioned above) where leadplant was abundant. Surveys for F. revisensis throughout the range of A. canescens are encouraged.

Types. Holotype ♂. Locality label (white): “Collected as larva on Amorpha canescens , USA: Illinois, Mason County, Revis Hill Prairie, +40o 9' 16.11" -89o 50' 51.28", 15-VI-2005, T. Harrison, emerged 3-VII-2005.”; determination label (red): “ HOLOTYPE Filatima revisensis ♂ Harrison, 2013 ”; deposited into the collection of the United States National Museum of Natural History, Washington, D. C. USA (hereafter, USNM). Paratypes. Three ♂♂, same locality label as for holotype except emerged 2-VII-2005, 3-VII-2005 and 4-VII-2005; one ♀, same locality label as for holotype except emerged 9-VII-2005; each paratype with determination label (blue): “ PARATYPE Filatima revisensis [gender symbol] Harrison, 2013” (USNM). Not included in type series. Ten ♂♂, ten ♀♀; locality label (white): “Collected as adult at UV light, USA: Illinois, Mason County, Revis Hill Prairie, 23- VI-2003, T. Harrison.”; determination label (white): “ GELECHIIDAE : Filatima revisensis [gender symbol] Harrison 2013 Det. T. Harrison, 2013” (USNM).

Etymology. The species is named for Revis Hill Prairie, Mason County, Illinois, the site from which it originally was reared.

Figures

FIGURE 1. Filatima revisensis. Adult, dorsal aspect. Scale bar = 5.0 mm.

FIGURE 2. Filatima revisensis. Scale morphology of adult abdominal terga. A, overview showing difference in coloration in segments 1 – 3 versus the posterior segments; B and C, detail of scales occurring on 1 st through 3 rd terga; D, detail of scales occurring on posterior terga.

FIGURE 3. Filatima revisensis. A, B, Sclerites of eighth abdominal segment of male adult. A, sternite, ventral aspect, flattened; B, tergite, dorsal aspect, flattened; C, mature larva.

FIGURE 4. Filatima revisensis. Male genitalia; all structures shown at same scale. A, valvae (lateral aspect) and vinculum (ventral aspect); CL, costal lobe of valva; MP, medial projection of saccular lobe of valva; AP, anteroventral projection of saccular lobe; VLP, VNP, processes of valva and vinculum, respectively, that attach to tegumen; VI, vinculum; B, tegumen and associated structures, ventral aspect; UN, uncus; GN, gnathos; TE, tegumen; VLC, VNC, points of connection to processes of valva and vinculum, respectively; C, phallus, ventral aspect.

FIGURE 5. Filatima revisensis. Female genitalia, ventral aspect. A, overview; OV, ovipositor; PA, posterior apophysis; DB, ductus bursae; AA, anterior apophysis; AB, appendix bursae; SI, signum; CB, corpus bursae; B, detail of structures associated with the anterior apophyses, ductus bursae, and corpus bursae.