Schrankia howarthi

Medeiros, Matthew J., Davis, Don, Howarth, Francis G. & Gillespie, Rosemary, 2009, Evolution of cave living in Hawaiian Schrankia (Lepidoptera: Noctuidae) with description of a remarkable new cave species, Zoological Journal of the Linnean Society 156 (1), pp. 114-139 : 125-133

SCHRANKIA HOWARTHI DAVIS & MEDEIROS

SP. NOV.

Similar to Schrankia altivolans in several morphological features, S. howarthi is a polymorphic, but predominantly smaller, more cavernicolous species that includes at least two relatively distinct forms: a generally smaller, indistinctly patterned, predominantly grey, deep cave (dark zone) adapted morph ( Fig. 2D ) and a slightly larger, more distinctly marked, cave entrance (twilight) to epigean form ( Fig. 2C ). The forewings of the deep cave morph usually measure ~ 4–7 mm in length and possess a mostly greyish ground colour with a variably faint pattern of slightly darker, transverse lines. The forewings of the twilight morph are typically larger (5.5–8.0 mm) and possess a variable pattern of more distinct whitish to brownish lines.

Description

Adult ( Fig. 3E–J ): Head: Vestiture mostly smooth, with low ridge sometimes evident projecting forward from vertex and from upper frons; scales moderately broad, possessing minutely dentate apices; generally pale brownish grey, occasionally paler brown laterally under antennal sockets. Antenna ~0.6¥ length of forewing; dense, piliform, pale grey cilia ventrally; cilia of male ~2¥ diameter of flagellomere in length, that of female ~1/2 the length of male cilia; a single row of moderately broad, pale grey scales dorsally over each flagellomere. Labial palpus variably pale to medium grey; second segment strongly compressed, usually with both dorsal and ventral margins slightly expanded and rough; apical segment smooth, slender, with nearly white apex.

Thorax: Generally medium to pale grey. Forewing: ground colour medium to pale grey with transverse lines varying from well marked to obscure; median band broad, irregular in outline, varying in colour from distinctly dark brown to grey and similar to ground colour; reniform usually included within medial band and indistinct; irregular antemedial and postmedial lines bordering medial band variably distinct, white to very pale grey; whitish subterminal line slender, sinuate, and usually interrupted in darker morphs to partitioned into a faint series of pale greyish white spots in most deep cave morphs; a series of often obscure dark brown adterminal spots positioned near ends of veins; fringe brown to grey. Hindwing: uniformly pale grey; base of fringe usually paler, more whitish.

Abdomen: Uniformly pale brownish grey.

Male genitalia ( Fig. 5C–F ): Uncus a single stout, elongate process, usually folded in repose ventrally between valvae, ~equal in length to moderately slender, V-shaped (inverted) tegumen. Vinculum well developed, broadly V- to U-shaped, ~ 1/2 the length of genital capsule. Juxta a small flat plate with paired slender, elongate, divergent processes anteriorly. Valva generally slender, gradually tapering to a slender, subacute apex bearing a prominent row of long, stout costal setae from subapical region; base of costa with a slender, elongate process ~0.6–0.7¥ length of uncus; ampulla a shorter, moderately stout truncate lobe 0.33–0.4¥ length of costal lobe, bearing usually six to eight elongate apical setae ~ the length of ampulla; sacculus terminating in a short, acute, slightly recurved lobe. Aedoeagus slender, gradually enlarging to a slightly swollen base; ejaculatory duct entering immediately above swollen base; cornuti consisting of numerous minute spines less than diameter of aedoeagus in length concentrated in a dense, elongate mass along ventral distal third, with a few loose cornuti occasionally scattered more basally through vesica.

Female genitalia ( Fig. 6B ): Eighth segment relatively well developed forming a moderately broad ring; caudal margin with a shallow midventral cleft; anterior apophysis reduced, ~1/3 length of posterior apophysis. Ostium located at termination of a sclerotized, external tube of variable length projecting caudally from anterior margin of eighth sternum; length of ostium tube ~0.6–0.8¥ length of posterior apophysis. Ductus bursae without spicules, elongate, slender; walls over caudal 2/3–3/4 densely wrinkled, but of approximately equal diameter throughout; length of ductus varying from 3.2–5.0¥ the length of eighth segment. Ductus seminalis from juncture of ductus bursae and corpus bursae; Corpus bursae ovate, ~0.4¥ length of posterior apophysis; a small external swelling present near juncture of ductus bursae; internal wall densely covered with rows of ~ eight to 12 minute spicules ( Fig. 6B ); signum a single, small, irregular plate studded internally with numerous short, stout, acute spines.

Larva ( Figs 2A , 7A–H , 8A–F , 9A–F ): Maximum length of larva examined 12.5 mm; maximum diameter 1.2 mm. Body pale cream to white (in alcohol); pinacula undeveloped on abdomen; anal shield pale brown. Head: Maximum width 0.7 mm. Colour pale yellowish brown. Chaetotaxy as illustrated ( Fig. 7A– H ); caudal 3/4 of cranium densely covered with minute microtrichia ( Fig. 8B, C ). Antenna arising from relatively deep pocket from anterolateral margin of cranium. Sensillae of antenna and maxilla as shown ( Figs 8D–F , 9A ). Stemmata ( Figs 7D , 8C ) usually with 2 to 4 distinct, 1 and 5 reduced, flat, 6 indistinct, possibly fused with 5. Labrum ( Fig. 7F, G ) with six pairs of dorsal setae, with M1, M3, La3 greatly reduced, M2, La2 the longest, and La1 of intermediate length; three pairs of stout epiphryngeal setae along anterior–ventral margin. Mandible ( Fig. 7H ) with four prominent, acute cusps with mesal cusp slightly reduced; lateral margins of cusps with minute, irregular serrations. Thorax: Pronotum and all pinacula nonpigmented (in alcohol), indistinct. D1 arising near middle of pronotum immediately below XD1; D2 arising lower and more caudad; SD1 and SD2 arising on small oblong pinnaculum narrowly separated from lower caudal angle of pronotum. Large prothoracic (cervical) gland present at midventer ( Fig. 8A ). Pretarsal claw elongate and slender; Coxae contiguous on all segments; T2 and T3 with relatively large tactile vesicle often evident on mesal surface of coxae ( Fig. 9C, D ).

Abdomen: Cuticle densely papillate, each papilla bearing ~9 minute, relatively stout microtrichia ( Fig. 10C ). D1 and D2 arising at nearly the same level on A1–4, A7–8 and with D1 higher on A5–6, with D1 below D2 on A9. Subventral setae bisetose on A1–4, A7–8; trisetose on A5–6. Anal shield with D1 arising caudally near D2. Prolegs present only on A5–6, 10; crochets homoideus, uniserial, containing ~13–16 hooks.

Cocoon ( Fig. 2D ): Approximately spindle-shaped, composed of numerous small, mostly elongate pieces of brownish tree roots orientated predominantly lengthwise; maximum length of main body ~ 10 mm, often with some plant fragments extending caudally an additional 5–7 mm; maximum width ~ 3–4 mm. Cocoon attached by silk at anterior end to usually vertical tree roots penetrating from cave roof.

Holotype: USA: HAWAII: Hawaii Island: Keauhou, Keamoku Cave , dark zone, 1725 m: ♂, 7.ii.1974, F. D. Stone & H. E. Smith (BPBM type # 16841). This specimen was selected from a large, very uniform series, many individuals of which were dissected.

Paratypes: USA: HAWAII: Maui Island: Kanaio Upper Cave , approx. 545 m east, dark zone: 7 ♂, 21.ix.1982, slide USNM 32928, F. D. Stone. Puu Mahoe, Ulupalakua Lava Tube no 2, dark zone, 670 m : 4 ♂, 22.ii.1988, 1 ♂, 26.ii.1988, 5 ♂, 27.viii.1977, 10 ♂, 28.viii.1977, 1 ♂, 27–28.viii.1977, em. 11.xi.1977, 1 ♀, 27–28.viii.1977, em. 13.ix.1977, 1 ♂, 27–28.viii.1977, em. 29.x.1977, slide USNM 32929, 1 ♀, 27–28.viii.1977, em. 31.x.1977, 1 ♂, 27–28.viii.1977, em. 4.xi.1977, 1 ♀, 27–28.viii.1977, em. 6.xi.1977, slide USNM 32930, 1 ♂, 27–28.viii.1977, em. 6.xi.1977, F. G. Howarth , 1 ♂, 28.viii.1977, slide USNM 33090, F. G. Howarth & G. K. Uchida. Hawaii Island: Blair Cave , dark zone, 1069 m : 1 ♂, 30.iv.1972, slide USNM 16960, F. G. Howarth. Blair Cave , near entrance, 1069 m : 1 ♂, 30.iv.1972, F. G. Howarth. Hawaii Volcanoes National Park: Ainahou Lava Tube , 900 m : 9 ♂, 4.i.1982, slide USNM 33084, F. D. Stone & F. G. Howarth; Ainahou Lava Tube , twilight deep, 855 m : 1 ♂, 24.x.1982, em. 6–7.xi.1982, F. G. Howarth. Hawaii Volcanoes National Park: Apua Cave , dark zone, 8–900 m : 12 ♂, 10.ii.1974, slide USNM 33083, F. G. Howarth; Mauna Loa Strip trail, Koa Tree Mold Cave , twilight zone, 1220 m : 3 ♂, 8.iii.1973, slide USNM 16955, F. G. Howarth; Petroglyph Cave , 975 m , twilight: 1 ♂, 21.ii.1980, F. G. Howarth; Thurston Lava Tube, [~ 1190 m] : 1 ♂, 15.vii.1976; Thurston Lava Tube, dark zone, 1200 m: 1 larva, 3.iii.1973, died 15.iii.1973, on tree roots, F. G. Howarth. Kaumana Cave, Mauka section, dark zone, 300 m : 1 larva, 2.x.1971, F. G. Howarth. Kaumana Cave , dark zone, 290 m : 2 ♂, 30.x.1972, F. G. Howarth. Keauhou Ranch, 7 km north of Kilauea, Keamoku Cave , dark zone, 1870 m : 2 ♂, 8 larvae, 11.xii.1976, larval slides USNM 20250, 28776, 35787, D. & M. Davis & F. Howarth. Kealakekua Ranch, Shelter Cave , dark & twilight zone, 1310 m : 25 ♂, 1 larva, 10.xii.1972, slides USNM 16757, 20251 (larva), F. G. Howarth, W. C. Gagne & J. Jacobi ; 1 ♂, 10.xii.1972, em. 21.xii.1972, 1 ♂, 10.xii.1972, em. 25.xii.1972, slide USNM 33570, 1 ♂, 21.xii.1972, F. G. Howarth. Kealakekua Ranch, Shelter Cave , dark zone, 1310 m : 1 ♀, 10.xii.1972, em. 18.xii.1972, slide USNM 17505, F. G. Howarth, W. C. Gagne & J. Jacobi. Kealakekua Ranch, Stone Wall Cave , twilight zone, 1225 m : 5 ♂, 1 ♀ 11.xii.1972, F. G. Howarth, W. C. Gagne & J. Jacobi. Kealakekua Ranch, upper Papaloa Cave, dark? Zone , 1600 m : 4 ♂, 1 ♀, 10.xii.1972, 1 ♂, 10.xii.1977, em. 17.xii.1972, slide USNM 16953, F. G. Howarth, W. C. Gagne & J. Jacobi. Keauhou, Keamoku Cave , dark zone, 1725 m : 2 ♂, 1 ♀, 7.ii.1974, F. D. Stone & H. E. Smith ; 3 ♂, 5.vii.1976; 1 ♀, 5.vii.1976, em. 9.vii.1976, F. G. Howarth ; 3 ♂, 8.vii.1976, F. G. Howarth ; 5 ♂, 10.vii.1976, F. G. Howarth & K. Sattler ; 1 ♀, 13.vii.1973, em. 30.vii.1973, F. G. Howarth. Keauhou Ranch, Aaa Keamoku Cave , dark zone, 1740 m : 3 ♂, 13.vii.1973, F. G. Howarth. Keauhou Ranch, Keamoku Cave , dark zone, 1725 m : 1 ♂, 11.xii.1976, em. 4.i.1977, F. G. Howarth. Keauhou Ranch, Keamoku Cave , 1800 m : 1 ♀, 11.xii.1976, em. 19.i.1977, 1 ♂, 11.xii.1976, em. 28.i.1977, slides USNM 33082, 33087, F. G. Howarth. Keauhou Ranch, Keawewai Cave # 4, twilight zone, 1800 m : 1 ♀, 10.xii.1976, em. 12.xii.1976, DRD lot 4325, D. R. Davis. Keauhou Ranch, Keauhou Ranch, Sandy’s Cave , dark zone, 1725 m : 1 ♂, 6.vii.1974, E. Smith. Kilauea, Aaa Keamoku , dark zone, 1725 m : 1 ♂, 8.vii.1976, em. 12.vii.1976; 1 ♂, 13.vii.1973, F. G. Howarth. Kilauea Forest Res. Cave No 2, twilight zone, 1650 m : 2 ♂, 27.iv.1972, D. R. Davis. Kipuka near Saddle Rd, Powerline Rd Cave , 1881 lava flow, dark zone upper passage, 1760 m : 1 ♂, 1 ♀, 10.iii.1973, F. G. Howarth. Kipuka on Saddle Rd, Powerline Rd Cave , dark zone lower passage, 1760 m : 2 ♀, 10.iii.1973, slide USNM 16952, F. G. Howarth. Kipuka on Saddle Rd, Powerline Rd Cave , dark zone upper passage, 1760 m : 1 ♂, 1 ♀, 10.iii.1973, slide USNM 17506, F. G. Howarth. Kipuka, Puaulu , 1250 m : 1 ♂, 6.vi.1976, F. G. Howarth. Kipuka, Puaulu, Bird Park Cave # 1, entrance : 1 ♂, 6.vi.1976, F. G. Howarth. Kurtistown Cave , dark zone, 168 m : 1 ♀, 7.iii.1976, F. G. Howarth. Kurtistown Cave (or Kazumura ), 168 m : 1 ♂, 1.iii.1976, F. G. Howarth. Kurtistown, Kazumura Cave , 168 m : 1 ♂, 7.iii.1976, F. G. Howarth. Kurtistown, Orchidland Caves , twilight zone, 168 m : 2 ♂, 18.ii.1974, F. G. Howarth. Lower Pahoa Cave , 180–190 m : 3 ♂, 1♀, 7.ii.1987, W. C. Gagné . Mountain View : Kazumura Lava tube, ~ 8 km SE Mountain View: dark zone, 170 m southeast of north-west end upper level room, 480 m: 5 ♂, 8.xii.1976, D. & M. Davis. Kazumura Lava tube, 400 m : 1 ♂,. viii.1979, F. G. Howarth. Kazumura Lava tube, dark zone : 2 ♂, 8.vi.1980, F. G. Howarth. Kazumura Lava tube, dark zone, 300 m : 4 ♂, 4.ix.1977, F. G. Howarth. Kazumura Lava tube, dark zone, 400 m : 4 ♂, 25.ii.1980; 10 ♂, 30.vii.1976, slide USNM 33091, K. Sattler ; 1 ♂, 14.viii.1977; 1 ♂, 28.x.1979; 2 ♂, 4.ix.1977, F. G. Howarth ; 2 ♂, 4.ix.1979, F. G. Howarth & S. L. Montgomery. Kazumura Lava tube, twilight zone, 400 m : 1 ♂, 1 ♀ 11.viii.1979, DRD 4326, F. G. Howarth. Mountain View: Bellows Cave, Kazumura , dark zone, 400 m : 3 ♂, 12.ii.1974, F. G. Howarth; Bellows Cave , Lava tube, dark zone, 300 m : 1 ♂, 4.ix.1979, F. G. Howarth & S. L. Montgomery. Kazumura Cave, 400 m : 1 ♂, 16.ii.1974, F. G. Howarth. Kazumura Cave , 1220 m from entrance, 400 m: 1 ♂, 13.vii.1972; 3 ♂, 14.vii.1972, slide USNM 16954; 3 ♂, 15.vii.1972, F. G. Howarth. Kazumura Cave , dark zone, 400 m : 3 ♂, 8.vii.1973, slide USNM 33081, F. G. Howarth ; 1 ♂, 30.vii.1976, K. Sattler ; 4 ♂, 1 ♀, 1.xi.1972, slides USNM 17518, 17517; 1 ♂, 8.xii.1972, F. G. Howarth. Mauna Loa: Bird Park Cave No. 1, 1220 m : 1 ♂, 9.xii.1976, D. & M. Davis; Bird Park Cave No. 2, 1250 m : 1 ♂, 9.xii.1976, D. & M. Davis. N. Kona, Huehue Ranch Cave , transition and dark zone, 600– 640 m : 10 ♂, 29.viii.1979, slide USNM 33085, F. G. Howarth. Pahoa, Pahoa Cave , dark zone, 150 m : 11 ♂, 1 ♀, 7.vii.1973, slides USNM 16958, 17504, F. G. Howarth. Powerline Rd, Pole 25, Emesine Cave , upper section, 1760 m : 1 ♂, 14.ii.1974, slide USNM 32933, F. D. Stone. Emesine Cave, Saddle Road , 1600 m , deep twilight: 6 ♂, 18.viii.1979, F. G. Howarth ; dark zone, lower section , 1 ♂, 18.viii.1977, F. G. Howarth, slide USNM 32931. Puna, Glenwood, Kokokahi Cave , dark zone, 756 m : 1 ♂, 31.viii.1977, F. G. Howarth. Puna, McKensie Park, McKensie Lava tube, dark, 15 m : 3 ♂, 1 ♀, 7.i.1985, F. G. Howarth & F. D. Stone. Puna, Pahoa Cave , dark zone, 150 m : 6 ♂, 20.viii.1977, slide USNM 33086; 3 ♂, 1.ix.1977, F. G. Howarth. Saddle Rd, Mauna Loa, Powerline Rd Cave , dark zone upper passage, 1760 m : 1 ♂, 18.iii.1973, F. G. Howarth . Paratypes deposited in BMNH, BPBM, and USNM.

Host: Most feeding records are from roots of presumed Metrosideros polymorpha , the dominant native rainforest tree and early pioneer on new lava flows, but S. howarthi is not host-specific. Cocoons and feeding damage have been observed on most types of available roots in caves, including Grevillea robusta , Eucalyptus spp. , Cocculus orbiculatus , pasture grasses, and many unidentified roots. Larvae are also attracted to a variety of rotting baits and appear to act as scavengers in caves. In the laboratory, they have been reared on sprouted corn roots.

Parasitoid: No parasitism has been observed. However, pupae and adults are frequently attacked by an unidentified fungus, which occasionally causes epizootics in cave populations.

Flight period: Adults and larvae are active throughout the year. Adult records are available for every month.

Distribution: This species normally occurs within the twilight to dark zone areas of lava tubes on the islands of Maui and Hawaii; however, it is sometimes found flying on the surface of both islands. The paler morph may be restricted to the dark zone of lava tubes.

Etymology: The species is named in honour of Dr Frank Howarth (Francis G. Howarth, author of this current paper), an entomologist at the Bernice P. Bishop Museum who has pioneered Hawaiian biospeleogy. Dr Howarth first discovered this species and collected most of the approximately 250 specimens examined.

FLIGHTLESSNESS – DROP TEST

A total of 54 S. howarthi was dropped in caves on Maui and Hawaii Islands ( Table 2). For dark-zone morph individuals, 31% of males (N = 26) and 50% of females (N = 2) were assessed to be ‘flightless’. For twilight-zone morph individuals, 5% of males (N = 19) and 43% of females (N = 7) were flightless. Each sex and morph of S. howarthi had at least one flightless individual and at least one individual that was capable of ascending flight. All ten control epigean individuals we dropped were capable of ascending flight, which is not surprising given that we caught them either while flying, or while perched after flying and landing on a blacklight sheet.

PHYLOGENETIC ANALYSIS

Species determinations for moths used in phylogenetic analysis were based upon the characters discussed in the individual species sections. We sequenced a total of 529 base pairs (bp) for COI, 509 from COII, and 451 for wingless. The concatenated COI, COII, and wingless fragments resulted in a character matrix 1489 bp in length containing 262 variable characters, 107 of which were parsimony informative. The number of parsimony informative sites was low for wingless (17 sites or only 4%). There were more informative sites for mtDNA (55 informative sites for COI, or 10% of sites; 35 for COII, 7%). When analysed on its own, wingless did not have any supported nodes, and the inclusion of wingless did not significantly alter the tree topology for any of the analytical methods below.

Maximum likelihood

The most likely tree is shown in Figure 11 . Bootstrap confidence is generally low, possibly because of homoplasy (as in Magnacca & Danforth 2006, 2007), short branch lengths and/or a lack of time since divergence between the two species of Hawaiian Schrankia , and even between the ingroup and outgroup taxa. The Hawaiian Schrankia appear to be monophyletic. Schrankia altivolans is shown to be a monophyletic group nested within the paraphyletic S. howarthi grade, with two exceptions: One S. altivolans individual captured on the surface of Hawaii Island is placed in the S. howarthi grade, as is one S. altivolans individual found in Kaumana Cave on Hawaii Island. One other S. altivolans found in Kaumana Cave is grouped with the other S. altivolans . Individuals which had wing patterns similar to each of the five original Hawaiian Schrankia species were scattered throughout the S. altivolans clade. All Maui S. howarthi individuals formed a subclade within the S. howarthi grade.

Bayesian inference

The topology of the recovered tree is similar to that of the maximum likelihood (ML) tree and the posterior probabilities for each of the supported nodes are indicated on Figure 11 . No nodes with a posterior probability> 50% were recovered that conflicted with any nodes, regardless of support level, of the ML tree. Schrankia altivolans still forms a monophyletic group nested within a paraphyletic S. howarthi grade, with the exception of the same two individuals. A large polytomy at the base of the ingroup limits resolution within the S. howarthi grade.

Maximum parsimony

Both PAUP* and PAUPrat found most parsimonious trees with a length of 434. A strict consensus of the first 10 000 most parsimonious trees found in PAUP* was largely in agreement with the Bayesian and ML trees, with one notable difference: S. howarthi moths from Emesine Cave on Hawaii Island combined with the S. altivolans clade to form a monophyletic group. However, this topology was not supported by bootstrapping: None of the nodes that had bootstrap values> 50% conflicted with any of the nodes generated through ML or Bayesian analysis.

Figures

Figure 2. Schrankia howarthi, habitat, larval feeding and pupation sites. A, dense concentration of tree roots from ceiling of Pahoa Cave, Hawaii Island. B, larva feeding on root, Kazumura Cave, Hawaii Island. C, adult resting on pupal cocoon, Kaumana Cave, Hawaii Island, twilight zone. D, adult resting on pupal cocoon, Pahoa Cave, Hawaii I., dark zone.

Figure 3. Hawaiian Schrankia adults. A, Schrankia altivolans, ♀, Upper Waiakea Forest Reserve, Stainback Highway, 930 m, on tree trunk, Hawaii Island (8.8 mm). B, S. altivolans, ♂, Aaa Kukai Cave, twilight zone, Hawaii Island (8.6 mm). C, S. altivolans, paratype ♂, Kaumana Cave, dark zone, Hawaii Island (5.5 mm). D, S. altivolans, ♂, Kealakekua Ranch Shelter Cave, twilight-dark zone, Hawaii Island (8.0 mm). E, Schrankia howarthi, paratype ♂, Kealakekua Ranch Shelter Cave, twilight zone, Hawaii Island (7.5 mm). F, S. howarthi, paratype ♂, Kealakakua Ranch Stone Wall Cave, twilight zone, Hawaii Island (6.5 mm). G, S. howarthi, paratype ♂, Kazumura Cave, dark zone, Hawaii Island (7.0 mm); H, S. howarthi, paratype ♂, Kealakekua Ranch Shelter Cave, dark zone, Hawaii Island (5.5 mm); I, S. howarthi, holotype ♂, Keauhou Ranch, Keamoku Cave, dark zone, Hawaii Island (5.8 mm). J, S. howarthi, paratype ♂, Ulupalakua Cave, dark zone, Maui Island (5.3 mm). Forewing lengths shown in parentheses.

Figure 5. Schrankia ♂ genitalia. A, Schrankia altivolans, slide 04a78, Maui Island: Haleakala National Park, Hosmer Grove; B, S. altivolans, slide 33088, Hawaii Island: Bird Park Cave; C, Schrankia howarthi, slide 33081, Hawaii Island: Kazumura Cave; D, S. howarthi, slide 33082, Hawaii Island: Keamoku Cave; E, S. howarthi, slide 4327, Hawaii Island: Stonewall Cave; F, S. howarthi, slide 32929, Maui Island: Ulupalakua Cave.

Figure 6. Schrankia ♀ genitalia. A, Schrankia altivolans, slide 33867, Hawaii Island: Hawaii Volcanoes National Park, Field Research Center; B, Schrankia howarthi, slide 17505, Hawaii Island: Kealakekua Ranch Shelter Cave.

Figure 7. Schrankia howarthi, Keamoku Cave, Hawaii Island, dark zone, slide 35787, chaetotaxy of late instar larva. A, lateral diagram of prothorax (T1), mesothorax (T2), and abdominal segments 1, 2, 6, 8, and 9. B, dorsal view of head. C, ventral view of head. D, lateral view of head. E, dorsal view of abdominal segments 8–10. F, dorsal view of labrum. G, ventral view of labrum. H, right mandible.

Figure 8. Schrankia howarthi, Keamoku Cave, Hawaii Island, dark zone, slide 28776, late instar larva. A, ventral view of head with antennae fully extended and prothorax (0.43 mm). B, lateral view of head (100 Mm). C, detail of stemmatal area in B (50 Mm). D, anterior view of retracted antenna (20 Mm). E, lateral view of antenna (43 Mm). F, anterior view of maxilla (20 Mm). Scale lengths given in parentheses.

Figure 9. Schrankia howarthi, slide 28776, late instar larva. A, apex of maxillary palpus (5 Mm). B, dorsal view of labial palpi and spinneret (20 Mm). C, ventral view of pro- and mesothorax (200 Mm). D, caudal detail of tactile vesicles in C (50 Mm). E, caudal view of metathoracic leg (100 Mm). F, lateral view of mesothoracic pretarsal claw (38 Mm). Scale lengths given in parentheses.

Figure 10. Schrankia howarthi, slide 28776, late instar larva. A, spiracular area of third abdominal segment (10 Mm). B, third abdominal spiracle (5 Mm). C, detail of third abdominal cuticle (5 Mm). D, left proleg of abdominal segment 5 (100 Mm); A, anterior, L, lateral. Scale lengths shown in parentheses.

Figure 11. Maximum likelihood phylogram. Bootstrap values greater than 50% are illustrated on tree as first value; Bayesian posterior probabilities are the second value. Values <50 are not labelled. Colours represent islands (black is Hawaii Island; red is Maui, blue is Oahu; green is Kauai). Asterisks denote flightless individuals. Black circles represent dark-zone morph Schrankia howarthi; grey circles represent twilight-zone individuals. Locality information for individual moths may be found in the Appendix.