Zaretis strigosus (Gmelin, [1790])

Dias, Fernando Maia Silva, Oliveira-Neto, José Francisco de, Casagrande, Mirna Martins & Mielke, Olaf Hermann Hendrik, 2015, External morphology of immature stages of Zaretis strigosus (Gmelin) and Siderone galanthis catarina Dottax and Pierre comb. nov., with taxonomic notes on Siderone (Lepidoptera: Nymphalidae: Charaxinae), Revista Brasileira de Entomologia 59 (4), pp. 307-319 : 311-314

Zaretis strigosus (Gmelin, [1790])

( Figs. 1–4 , 9–22 , 27–29 , 33–34 , 37–39 , 43 )

Biology: Eggs are laid singly underneath leaves of Casearia sylvestris ( Salicaceae ) ( Fig. 44 ) in all study sites; all instars feed at night, resting inconspicuously during most of the day; first instar eclodes by chewing a round aperture around the dorsal concave depression of the egg; first and second instars feed initially on the apex of leaves, building and resting on frass chains made out of silk, fecal pellets and parts of the host plant (e.g. Fig. 45 ), considerably extending the midrib; third to fifth instars rest on twigs or on the midrib of either fresh or partially consumed leaves of the host plant, resembling a piece of rolled-up, dead leaf; third to fifth instars move in a wobbling fashion, resembling a dead leaf being blown by the wind; when close to pupation, the fifth instar stops eating and occasionally leave the host plant to find a suitable place to pupate, then, the larva weaves a thick silk pad underneath a leaf, attaching itself head capsule down by the anal abdominal legs, remaining somewhat coiled until molting; pupae are incapable of movement; at the emergence of the adult, an amount of reddish orange meconium is expelled.

Egg:Pale yellow; nearly spherical, with a dorsal concave depression around the micropyle; chorion smooth; aeropyle as minute bumps around the edge of the dorsal concavity. Egg width: 0.9 mm (n = 1). Duration: 6 days.

First instar ( Figs. 9–10 , 23–26 ): Head capsule rounded and smooth; mostly dark brown, with whitish anterior and lateral areas and translucent setae; body almost cylindrical, slightly larger at A2 and slightly tapering posteriad, A9 + 10 with a small fleshy projection; body yellowish green, with brown setae with creamy white bases, and a creamy white line along the body on the supraspiracular area, displaced dorsally on A2, A8–A9 + 10 brownish green; prothoracic plate divided at the midline, each part trapezoidal; anal plate rounded, weakly defined; abdominal leg plates semicircular; thoracic legs, prothoracic plate, anal plate, abdominal leg plates and ocrea dark brown. Abdominal legs with 14 and anal legs with 11 crochets, both arranged as a unisserial, uniordinal lateral pennelipse. Head capsule chaetotaxy and stemmata position, and body chaetotaxy, spiracle size and relative position are shown in Figs. 23–26 . Head capsule size: 0.67 mm (n = 1). Duration: 7 days.

Second instar ( Figs.11, 12 , 27 ): Head capsule brown, lighter than in previous instar, with scattered creamy yellow tiny knobs and two truncated, dorsal and more or less paralleled projected horns, about one-tenth the height of the head capsule, one on each side of the epicranial suture. Body with T1 about the same size of the head capsule, enlarging posteriorly toward A2, then gradually tapering to A9 + 10; A9 + 10 with a dorsal squared fleshy projection with tips slightly projected; body yellowish green dorsally and laterally, reddish green ventrally; base of the setae creamy yellow, with two supraspiracular creamy yellow lines, one from T1 to half of A1, and another from the dorsal area of A2 to the subdorsal area of the same segment, forming an anterior angle and then running posteriad on the supraspiracular area toward to the end of the A9 + 10 projection. Head capsule size: 0.95 mm (n = 2). Duration: 5–6 days.

Third instar ( Figs. 13, 14 , 28 ): Head capsule similar to the previous instar but horns conspicuously larger, about half the height of the head capsule; labrum, anteclypeus, frontoclypeus and the anterior area of the epicranium dark brown, with lighter areas between the horns and along the epicranial suture, lateral and posterior area of the epicranium greenish brown; body shape similar to the previous instar, but thorax conspicuously thicker in A2, with lateral triangular fleshy projections, and dorsal squared fleshy projection in A9 + 10 strongly developed; body mostly greenish brown, speckled with creamy white and yellow on the base of small setae; T1–A1 supraspiracular line creamy white; A2–A9 + 10 supraspiracular line similar to the previous instar, but light yellowish green; A3–A9 + 10 subdorsal areas with a series of oblique creamy white lines forming a trapezoidal and lozenge-shaped pattern; A3 with a small dorsal trapezoidal lighter area; A5 with a dorsal hourglass-shaped lighter area, darker in the adjacent subdorsal areas; A6 with a large dorsal trapezoidal lighter area; A7 similar to A5, but markedly dark brown in the subdorsal area adjacent to the dorsal lighter area; combined dorsal lighter areas of A6–A8 roughly forming a lozenge; A8 and A9 + 10 lighter greenish brown dorsally; A9 + 10 posteriorly reddish green. Head capsule size: 1.5 mm (n = 2). Duration: 6–7 days.

Fourth instar ( Figs. 15, 16 , and 29): Head capsule shape similar to the previous instar, but larger and dark brown, with a lateral whitish line ventral to the head horns, more or less continuous with the T1–A1 supraspiracular line; horns about two-thirds the height of the head capsule; body shape and color similar to the previous instar but larger, with color pattern darker and more noticeable; fleshy projections of A2 larger. Head capsule size: 2.25 mm (n = 3). Duration: 8–9 days.

Fifth instar ( Figs. 17–19 , 33–34 ): Head capsule shape and color similar to the previous instar, but larger ( Fig. 19 ); body shape similar to the previous instar, but thorax even thicker and humped at A2, with enlarged lateral triangular fleshy projections; thoracic legs red; body color mostly dark greenish brown, similar to the previous instar, but color pattern posterior to the dorsal line in A2 and dorsal to the A2–A9 + 10 supraspiracular line formed by poorly defined whitish oblique markings; A7 similar to the previous instar, with dark brown and greenish brown subdorsal and posterior greenish brown dorsal areas; A8 with a dorsal trapezoidal greenish brown area; A9 + 10 dorsally greenish brown; abdominal legs crochets arranged as a unisserial, triordinal interrupted mesoseries and anal legs arranged as a unisserial, triordinal mesal pennelipse. Head capsule size: 3.66 mm (n = 3). Duration: 12–14 days.

Pupa ( Figs. 20–22 , 37–39 ): Mostly uniformly light green, creamy yellow around the cremaster. Head and prothorax narrower than the rest of the thorax and abdomen, abdomen wider than thorax, the latter medially narrower in dorsal and ventral view; pupa with two sets of strongly developed creamy white carinae: one lateral, runs continuously from the vertex posteriorly to the edge of the mesothoracic wing cases, and another across A4; abdomen strongly compressed, somewhat conical; scape and pedicel dorsal, the former larger than the latter; antennae flagellum extending ventrally and posteriorly between the mesothoracic wing cases; eye cases lateral and divided into one rough and other smooth area; frons and clypeus weakly separated from genae, anterior tentorial fovea visible between these areas; mandible trapezoidal and wide; labium somewhat lozenge-shaped, between the mandibles; galae slightly wider than mandibles basally, extending and tapering between the mesothoracic legs. Prothorax trapezoidal; mesothoracic spiracle between prothorax and mesothorax; mesothorax dorsally bulged; mesothoracic wing cases ventral, wing shape and venation visible; prothoracic and mesothoracic legs between the galae and the mesothoracic wing cases, the former approximately two-thirds the size of the latter; metathorax ‘M’ shaped; metathoracic wing cases extending posteriad and ventrally between the abdomen and the mesothoracic wing cases. A1–A4 partially covered by the meso end metathoracic wing cases ventrally; first spiracle not visible; spiracles on A2 and A3 dorsal, close to the metathoracic wing cases, and the others lateral; A5–A6 conical and compressed; genital scars slits on A 9 in males and A8 and A 9 in females; cremaster mostly black, directed ventrally and surrounded by creamy yellow set of tubercules: one set anterior and lateral to the yellowish green anal scar, one on each side of the shaft of the cremaster, and one dorsal to the shaft of the cremaster. Shaft slightly curved ventrally, with several tiny hooks at the tip. Length: 1.033 cm; height: 1.5 cm; cremaster height: 1.75 mm (n = 3). Duration: 12–14 days.

Discussion: The immature stages of Z. strigosus were illustrated by Sepp [1829] and Rydon (1971), and described by Müller (1886). Müller’s (1886) description is based on S. galanthis catarina comb. nov. (misidentified as S. ide Hübner, [1823] ), highlighting only the differential characters between these two species. There is no noticeable difference between the immature stages described by Müller (1886) and the description given here. Biezanko et al. (1966, 1974) and Brown (1992) reported Casearia sylvestris ( Salicaceae ) as preferred host plant; Zikán and Zikán (1968) and ( Silva et al., 1968) report the use of species of Colubrina ( Rhamnaceae ) as the host plant of Z. strigosus , but those unusual records needs confirmation. Nevertheless, there are a number of other host plant records in the literature ( Beccaloni et al., 2008) that cannot be ascertained to a specific species of Zaretis , given the confused taxonomy of the genus. These records are all in the Salicaceae , of species of Casearia , Laetia , Xylosma , Zuelania and Ryania ; DeVries (1986) reports an unusual record in the Piperaceae . Janzen and Hallwachs (2015) illustrate fourth and fifth instar and pupae of species of Central American Zaretis , with host plant records, and reports of parasitism by Tachinidae flies and Braconidae wasps. Other species of Zaretis with detailed description are Z. ellops and Z. callidryas , described by Muyshondt (1973, 1976) (the former identified as Anaea (Zaretis) itys (Cramer, [1777])) , both reported to feed on C. sylvestris and C. nitida . Although similar, the larvae of Z. callidryas can be easily distinguished by the smoother head capsule, longer and posteriorly curved head horns, and much lighter dorsal color posterior to the A2 hump; on the other hand, Z. ellops and Z. strigosus are almost identical, varying only in the coloration of the dorsal area posterior to the A2 hump. Zaretis ellops and Z. strigosus are likely sister species; they are similar not only in the morphology of the immature stages, but also in the morphology of the adults. Nevertheless, while Z.ellops only occurs in west of the Andes and Central America, Z. strigosus is restricted to South America east of the Andes.

Taxonomic comments: Zaretis strigosus is frequently misidentified as Z. itylus (Westwood, 1850) and Z. isidora (Cramer, [1779]) ; indeed the name strigosus was synonymized with isidora by Willmott and Hall (2004), but the name was later resurrected by a number of authors in faunistic studies (e.g. Francini et al., 2011; Morais et al., 2012; Bellaver et al., 2012). Due to the intrinsic intraspecific variation and sexual dimorphism found in most species of the genus, there is no consensus among authors about the number of species of Zaretis and the correct name to apply to each phenotype. Nevertheless, morphologic and molecular evidence support the validity of Z. strigosus and a number of cryptic

Figures

Figs. 1–4. Zaretis strigosus (Gmelin, [1790]) (Santa Catarina, Brazil). 1 and 2: Male, dorsal and ventral. 3 and 4: Female, dorsal and ventral. Scale bar =1 cm.

Figs. 9–22. Immature stages of Zaretis strigosus (Gmelin, [1790).9 and 10: First instar, lateral and dorsal.11 and 12: Second instar, lateral and dorsal.13 and 14: Third instar, lateral and dorsal. 15 and 16: Fourth instar, lateral and dorsal. 17 and 18: Fifth instar, lateral and dorsal. 19: Fifth instar, head capsule, anterior view. 20–22: Pupa, ventral, dorsal and lateral views. Scale bars= 1 mm.

Figs. 27–32. Head capsules of second to fourth instars in anterior view. 27–29: Zaretis strigosus (Gmelin, [1790]). 27: Second instar. 28: Third instar. 29: Fourth instar. 30–32: Siderone galanthis catarina Dottax and Pierre, 2009 comb. nov. 30: Second instar. 31: Third instar. 32: Fourth instar. Scale bar, Figs. 27, 30 =0.25 mm, Figs.28, 29, 31 and 32 =0.5mm.

Figs. 33–36. Head capsules of fifth instars in anterior and lateral views. 33 and 34: Zaretis strigosus (Gmelin, [1790]). 35 and 36: Siderone galanthis catarina Dottax and Pierre, 2009 comb. nov. Scale bar =1 mm.

Figs. 37–42. Pupae in ventral, dorsal and lateral views. 37–39: Zaretis strigosus (Gmelin, [1790]). 40–42:Siderone galanthis catarina Dottax and Pierre,2009 comb. nov. Scale bar= 0.5cm.

Fig. 43. Male genitalia of Zaretis strigosus (Gmelin, [1790]), lateral. Scale bar= 0.5mm.

Figs. 44–57. Host plant and immature stages of Siderone galanthis catarina Dottax and Pierre,2009 comb. nov. 44: Host plant, Casearia sylvestris (Salicaceae). 45: Egg,lateral. 46: Second instar resting in frass chain. 47: Second instar, dorsal. 48 and 49: Third instar, lateral and dorsal. 50 and 51: Fourth instar, lateral and dorsal. 52 and 53: Fifth instar, lateral and dorsal. 54: Fifth instar, head capsule in anterior view. 55 and 56: Pupa, ventral, dorsal and lateral views. Scale bars= 1 mm.

Figs. 23–26. Schematics of the first instar of Zaretis strigosus (Gmelin, [1790]) and Siderone galanthis catarina Dottax and Pierre, 2009 comb. nov. 23 and 24: Head capsule, anterior and posterior. 25: Prothoracic plate, dorsal. 26: Thorax and abdomen, lateral.