﻿Five new species of Bradina Lederer (Lepidoptera, Crambidae) from China, with remarks on the morphology of the genus

﻿Abstract Bradina is a species-rich genus that differs from most other Spilomelinae genera because of its distinctive wing venation. Most species of this genus are very similar in appearance. In this study, we have studied morphological characteristics of the genus and eight closely related species from China. Among them, B.falciculata Guo & Du, sp. nov., B.fusoidea Guo & Du, sp. nov., B.spirella Guo & Du, sp. nov., B.ternifolia Guo & Du, sp. nov. and B.torsiva Guo & Du, sp. nov. are described as new to science. Bradinamegesalis (Walker, 1859), B.translinealis Hampson, 1896 and B.subpurpurescens (Warren, 1896) are redescribed based on their holotypes and additional material, and the latter two are newly recorded from China and their genitalia are described for the first time. The images of the habitus and genitalia of these eight species are provided, with a key to their identification.


Introduction
Bradina Lederer, 1863 is the most species-rich genus in the Spilomelinae tribe Steniini Guenée, 1854, redefined by Mally et al. (2019). So far, there are 89 species recorded in this genus worldwide (Nuss et al. 2003(Nuss et al. -2023 and they are mainly distributed in the Oriental and Australian regions. Numerous endemic species are present in the Australian and Pacific islands. In Spilomelinae, Bradina can be differentiated from most other genera by the forewings with Rs 1 anastomosed with Rs 2 +s 3 at the base, which is common in Acentropinae. Therefore, this genus was placed in Hydrocampinae (= Acentropinae Stephens, 1835) for a long time (Hampson 1896;Hampson 1897;Rothschild 1915;Schaus 1924;Caradja 1925). Inoue (1955) transferred the genus to Pyraustinae (s. l.). Systematics research on Bradina is inadequate globally besides some early studies (Hampson 1896;Hampson 1897;Yamanaka 1984;Du 2008). Seizmair (2021) recorded Bradina from the Arabian Peninsula and divided the genus into seven groups according to wing pattern.
Species identification of Bradina is difficult because of their very similar appearance, so the genitalia characteristics are necessary in the identification of most species. The large spinose crescent-shaped signum of the female genitalia is a diagnostic characteristic of the genus, but shows little difference among species. In male genitalia, the valvae and uncus are very diverse in morphology, which is very valuable for interspecific identification. Before this study, 13 species were recorded in China (Lu and Guan 1953;Wang and Speidel 2000;Du 2008). In the present study, eight Bradina species with externally similar adults and male genitalia morphology are recorded, including five new species and two newly recorded species from China.

Materials and methods
Specimens examined, including the types of new species, are deposited in the College of Plant Protection, Southwest University, Chongqing, China (SWU) except for two holotypes and 38 paratypes which are deposited in the Insect Collection of the College of Life Science, Nankai University, Tianjin, China (NKU). The corresponding author examined many specimens of Bradina deposited in Natural History Museum, London, United Kingdom (NHMUK), including some types.
The photographs of the adults were taken with a digital camera (Canon EOS 5D), and those of the genitalia were obtained with a digital camera (Leica DFC 450) attached to a stereomicroscope (Leica M205 A).
The preparation of genitalia mainly follows Li and Zheng (1996). Morphological terminology mainly refers to Maes (1995) as well as Mally and Nuss (2011).

Bradina Lederer, 1863
Bradina Lederer, 1863: 424. Klima 1937. Diagnosis. Head (Fig. 1A). Frons rounded. Antenna annulated, male with short cilia ventrally. Labial palpus obliquely upturned, second segment with broad scales ventrally, third joint minute and forward, apex blunt. Maxillary palpus filiform. Thorax. Forewing long and narrow usually; length of cell c. half of wing; discocellulars incurved; R from cell at c. four fifths above; Rs 1 anastomosed with Rs 2 +s 3 at base and with a long stalk c. two fifths of Rs 3 ; Rs 2 and Rs 3 stalked c. three fifths of Rs 3 ; basal half of Rs 4 straight and clearly separated from Rs 1 +s 2 +s 3 ; M 2 , M 3 and CuA 1 uniformly from posterior angle of cell at base (except for B. diagonalis Hampson, 1896); CuA 2 from cell at three quarters below. Hindwing with length of cell c. one third of wing; discocellulars incurved; Sc+R and Rs stalked c. one third of Rs; Rs and M 1 from anterior angle of cell; M 2 , M 3 and CuA 1 uniformly from posterior angle of cell; CuA 2 from cell at four fifths below (Fig. 1B). Legs long and slender; middle tibia with outer distal spur c. half-length of inner spur. Abdomen. Male abdomen long and slender (except for B. melanoperas Hampson, 1896). Male genitalia. Uncus diverse, apex with setae dorsally. Valva narrow or broad, some with well-developed setal cluster. Saccus developed. Phallus long and cylindrical.
Remarks. The generic characteristics were summarized by Khan (2000), but the description about wing venation was incomplete. In addition, the lengths of the maxillary palpus and labial palpus were identical in Khan's description, while we found that both have their ends at the same height but they are of different lengths. Therefore, the generic characteristics are revised in the present study.
The bodies of Bradina species are usually brown, yellowish brown, or pale brown, except for a few species with white bodies, and have nearly identical wing markings. The male genitalia, on the other hand, are very diverse among species of this genus. We found that the male genitalia can be divided into three types according to the morphological characteristics of the valvae. The first type, represented by B. admixtalis, have long and narrow valvae; the second type, represented by B. melanoperas, have short and broad valvae; the third type, represented by B. megesalis, have broad valvae in which the costa is arched near the base or middle. Species in the present study have the third valva type, accompanied by the following common characteristics: body brown of various shades. Uncus broad, distal part bilobed, with dense short setae dorsally. Valva broad; costa arched near base or middle and accompanied by a cluster of long setae, usually followed by a depression. Saccus nearly trapezoidal, slightly concaved terminally. Juxta nearly rounded, split posteriorly. Phallus distinctly inflated at anterior end. Apophyses anteriores expanded at c. one third from base.  Frons brown, with lateral sides white above. Vertex yellowish white. Antenna brownish yellow, with black ring dorsally; ventral cilia c. one quarter length of diameter of male flagellomeres. Labial palpus with basal two thirds white, black-brown distally. Maxillary palpus yellowish brown, white at base. Patagium pale brown, yellowish. Thorax white ventrally. Forewing pale brown, darker along basal two thirds costa, stigmata and lines brown; discoidal stigma crescent; postmedial line at c. two thirds of wing, straight and nearly parallel to terminal margin. Hindwing with postmedial line and discoidal stigma pale brown, inconspicuous usually; discoidal stigma crescent. Cilia pale brown, yellowish white on inner margin of hindwing. Legs pale yellow, coxae and femora with white gloss. Middle tibia brown; hind tibia with outer middle spurs c. two thirds length of inner spurs. Abdomen pale brown dorsally, with each segment pale terminally; yellowish white ventrally.
Male genitalia (Fig. 3A, B). Valva distally gradually narrowed and bearing dense long setae; costa sharply arched near middle and accompanied by a cluster of long curved setae; sacculus gradually narrowed to apex, with a cluster of long setae near middle. Posterior phallus with two developed spear-like cornuti.
Remarks. We found that the coremata of some male individuals of this species were protruded out of the body, forming a cluster of white hairs at the end of the abdomen. Diagnosis. This species is similar to B. megesalis. The difference in appearance is that the distance between discoidal stigma and postmedial line on forewing of this species is longer than that of B. megesalis; the postmedial line and terminal margin of forewing is obviously unparallel in this species, while is nearly parallel in the latter. It also can be distinguished by the setal cluster near middle of sacculus being shorter than that of the latter, phallus with one fusiform cornutus and one subcircular cornutus (two spear-like cornuti in B. megesalis), posterior ductus bursae inflated but not forming irregular protrusion as in B. megesalis, plus subposterior section of ductus bursae widened along half of ductus length, a feature that is absent in B. megesalis.

Bradina fusoidea
Description. Adult (Fig. 2B) white line at base, except yellowish white on inner margin of the hindwing. Legs pale yellow. Front and middle tibiae brown; hind tibia with outer middle spurs c. two thirds length of inner spurs. Abdomen with basal half pale brown and distal half dark brown dorsally, each segment pale terminally; yellowish white ventrally.
Male genitalia (Fig. 3F-H). Valva distally gradually narrowed and bearing dense long setae; costa arched near middle and accompanied by a cluster of long curved setae; sacculus gradually narrowed to apex, with a cluster of long setae near middle. Phallus with one fusiform cornutus medially, composed of short and blunt spines, c. one third length of phallus, and one subcircular sclerotized cornutus posteriorly.
Etymology. The specific name is derived from the Latin fusoideus (meaning 'fusiform'), in reference to a fusiform cornutus.
Distribution. China (Guangdong, Sichuan). Diagnosis. This species is similar to B. megesalis. The difference in appearance is that wings of this species are darker in color and hindwings are slightly broader; the postmedial line and terminal margin of forewing are obviously unparallel in this species, while nearly parallel in the latter. It also can be distinguished by phallus with one short, spiral band-like cornutus and two lamellar cornuti, and some tiny spines on the vesica medially; the posterior ductus bursae is inflated into a thick finger-like protrusion. In B. megesalis, the phallus has two spear-like cornuti and is without spines on the vesica; the posterior ductus bursae is inflated into an irregular protrusion.

Bradina spirella
Description. Adult (Fig. 2C). Wingspan 29.0-32.0 mm, forewing length 14.0-15.5 mm. Frons brown, with lateral sides yellowish white above. Vertex pale yellow. Antenna brownish yellow, with black-brown ring dorsally, basal segments of flagellum black-brown dorsally; ventral cilia c. one third length of flagellomere diameter of male. Labial palpus with basal two thirds white, black-brown distally. Maxillary palpus black-brown. Patagium and tegula dark brown. Thorax dark brown dorsally, white ventrally. Wings dark brown, stigmata and lines black-brown. Forewing black-brown along costa, slightly paler distally; orbicular stigma very small; discoidal stigma crescent; postmedial line at c. two thirds of wing, inconspicuously waved and unparallel to terminal margin. Hindwing pale at base; postmedial line straight, only middle part obvious. Cilia greyish brown. Legs pale yellow. Front and middle tibiae dark brown; hind tibia with outer middle spurs c. same length as inner spurs. Abdomen brown dorsally, with each segment pale terminally; yellowish white ventrally.
Male genitalia (Fig. 3L, M). Valva with the distal part gradually narrowed and bearing dense long setae; costa arched near middle and accompanied by a cluster of long curved setae; sacculus gradually narrowed to apex, with a cluster of long setae near middle. Juxta narrowed distally. Phallus with one short and spiral band-like cornutus tapered at posterior end, along with two lamellar cornuti in posterior half; some tiny spines on vesica medially.
Etymology. The specific name is derived from the Latin spirellus (meaning 'small spiral-like'), in reference to a short and spiral band-like cornutus.
Distribution. China (Hunan, Jiangxi). Remark. Coremata of some male individuals of this species were protruded out of the body, forming a cluster of white hairs at the end of the abdomen. Diagnosis. This species is similar to B. megesalis. The difference in appearance is that wings of this species are darker in color, and hindwings are slightly broader; the postme-dial line and terminal margin of forewing is obviously unparallel in this species, while it is nearly parallel in the latter. It also can be distinguished by the sacculus without long setal cluster, the phallus with one broad, spiral, band-like cornutus; the posterior third of ductus bursae with slightly sclerotized elongate inflation, but not forming irregular protru- sion. In B. megesalis, the sacculus has long setal cluster near middle, and the phallus has two spear-like cornuti; the posterior ductus bursae is inflated into an irregular protrusion.

Bradina torsiva
Description. Adult (Fig. 2D). Wingspan 36.0-37.0 mm, forewing length 17.5-18.0 mm. Frons brown, with lateral sides yellowish white above. Vertex yellowish white. Antenna brownish yellow, with black-brown ring dorsally, ventral cilia c. half-length of flagellomere diameter of male. Labial palpus with basal two thirds white, black-brown distally. Maxillary palpus black-brown or brown. Patagium yellowish white. Tegula dark brown. Thorax dark brown dorsally, white ventrally. Wings dark brown, stigmata and lines black-brown. Forewing black-brown along costa, slightly paler distally; orbicular stigma very small; discoidal stigma crescent; postmedial line at c. two thirds of wing, unparallel to terminal margin. Hindwing slightly pale at base; postmedial line inconspicuously waved, only middle part obvious. Cilia pale yellow, with a blackbrown line at base, except black-brown on inner margin. Legs yellow. Front and middle tibiae dark brown; hind tibia with outer middle spurs c. three fifths length of inner spurs. Abdomen brown dorsally, each segment pale terminally; paler ventrally.
Male genitalia (Fig. 4A, B). Valva with the distal part gradually narrowing and with dense long setae; costa arched near middle and accompanied by a cluster of long curved setae; sacculus narrowed distally, without long setal cluster. Juxta narrowed distally. Phallus slightly inflated, with one broad and spiral band-like cornutus posteriorly.
Etymology. The specific name is derived from the Latin torsivus (meaning 'spiral'), in reference to a spiral band-like cornutus.
Distribution. China (Guangdong, Hunan). Remark. Coremata of some male individuals of this species were protruded out of the body, forming a cluster of white hairs at the end of the abdomen.  (Fig. 2E). Wingspan 26.0-33.0 mm, forewing length 14.5-16.0 mm. Frons brown, with lateral sides white above. Vertex brownish yellow. Antenna brownish yellow, with pale brown ring dorsally; length of ventral cilia c. one quarter of the flagellomere diameter of male. Labial palpus with basal two thirds white, black-brown distally. Maxillary palpus black-brown, pale brown at base. Patagium and tegula brown. Thorax pale brown distally, white ventrally. Wings dark brown, stigmata and lines black-brown. Forewing black-brown along basal costa; orbicular stigma very small; discoidal stigma crescent; postmedial line at c. three quarters of wing, nearly parallel to terminal margin, slightly excurved near costa. Hindwing with postmedial line slightly beyond basal half of wing, only middle part obvious. Cilia pale brown on forewing, yellowish white on hindwing; a brown line at base. Legs pale yellow. Front and middle tibiae yellowish brown; hind tibia with outer middle spurs c. half-length of inner spurs. Abdomen pale yellowish brown dorsally, each segment pale terminally.
Remarks. This species is recorded in China for the first time, and its male genitalia are also described for the first time. It can be distinguished from the other species (except B. falciculata) in the present study by the forewing relatively narrower; cilia pale brown on forewing, yellowish white on hindwing. The female of this species is unknown. Diagnosis. This species is similar to B. subpurpurescens. The difference in appearance is that wings are paler in color and the postmedial line of the forewing is placed at two thirds from the wing base in this new species, but at three quarters in the latter. It also can be distinguished by an elliptical valva and the phallus inconspicuously inflated distally. In B. subpurpurescens, the valva is nearly rectangular and the phallus is significantly inflated distally.

Bradina falciculata
Description. Adult (Fig. 2F). Wingspan 25.0-27.0 mm, forewing length 12.0-13.0 mm. Frons brown, with lateral sides yellowish white above. Vertex yellowish white. An-tenna yellow, with pale brown ring dorsally; ventral cilia c. half-length of flagellomere diameter of male. Labial palpus with basal two thirds white, dark brown distally. Maxillary palpus dark brown. Patagium and tegula pale brown. Thorax pale brown dorsally, white ventrally. Wings yellowish brown, stigmata and lines brown. Forewing with discoidal stigma crescent; postmedial line at basal two thirds of wing, slightly excurved and nearly parallel to terminal margin. Hindwing with postmedial line straight, usually not obvious. Cilia pale brown, with a darker line at base, except greyish white on inner margin of the hindwing. Legs pale yellow. Front and middle tibiae black-brown on distal half; hind tibia with outer middle spurs c. half-length of inner spurs. Abdomen pale brown dorsally, yellowish white ventrally.
Male genitalia (Fig. 4H-J). Valva elliptical; costa arched near middle and accompanied by a cluster of long curved setae; sacculus gradually narrowed to apex, without long setal cluster. Juxta narrowed distally. Phallus with one small fusiform cornutus anteriorly, composed of short and blunt spines, c. one sixth length of phallus, and with two sickle-shaped cornuti posteriorly.
Etymology. The specific name is derived from the Latin falciculatus (meaning 'falcate'), in reference to two sickle cornuti of posterior phallus.
Distribution. China (Tibet). Redescription. Adult (Fig. 2G). Wingspan 25.0-30.0 mm, forewing length 12.0-13.0 mm. Frons brown, with lateral sides yellowish white above. Vertex yellowish white. Antenna brownish yellow, with brown ring dorsally; ventral cilia c. quarter length of flagellomere diameter of male. Labial palpus with basal two thirds white, black-brown distally. Maxillary palpus black-brown, yellowish white at base. Patagium and tegula pale brown. Thorax pale brown dorsally, white ventrally. Forewing yellowish brown, dark brown along basal half of costa; stigmata and lines black-brown; discoidal stigma reniform; postmedial line at c. two thirds of wing, slightly excurved near costa. Hindwing pale yellowish brown dorsally, yellowish white to pale brown ventrally; paler at base; postmedial line pale brown, inconspicuous, extending beyond basal half of wing. Cilia pale brown on forewing, yellowish white on hindwing, a brown line at base. Legs yellowish white. Front and middle tibiae brown; hind tibia with outer middle spurs c. half-length of inner spurs. Abdomen pale yellowish brown dorsally, yellowish white ventrally.
Remarks. This species is first recorded in China and its genitalia are described for the first time. It can be distinguished by the valva being nearly elliptical, the phallus with one fusiform cornutus medially and two weakly sclerotized lamellar cornuti posteriorly. Diagnosis. This species is similar to B. translinealis. It can be distinguished by postmedial line of forewing straight; valva elongated and narrowed comparatively, sacculus with long setal cluster near middle, posterior phallus with three long leaf-like cornuti; antrum membranous. In B. translinealis, postmedial line of forewing slightly excurved near costa; sacculus has no setal cluster, phallus has one fusiform cornutus medially and two lamellar cornuti posteriorly; antrum broader and sclerotized.

Bradina ternifolia
Description. Adult (Fig. 2H). Wingspan 31.0-33.0 mm, forewing length 15.0-16.0 mm. Frons brown, except black-brown above. Vertex yellowish white mixed with brownish yellow. Antenna pale yellow, with pale brown ring dorsally; ventral cilia c. half-length of flagellomeres diameter of male. Labial palpus with basal half yellowish white, brown or black-brown distally. Maxillary palpus brown or blackbrown. Patagium and tegula dark brown. Thorax dark brown dorsally, white ventrally. Wings brown, stigmata and lines black-brown. Forewing black-brown along costa; discoidal stigma reniform; postmedial line at c. two thirds of wing, straight and nearly parallel to terminal margin. Hindwing with discoidal stigma crescent; postmedial line beyond basal half of wing, usually inconspicuous. Cilia pale brown on forewing, greyish white on hindwing, a darker line at base. Legs pale yellow. Front and middle tibiae brown; hind tibia with outer middle spurs c. three fifths length of inner spurs. Abdomen dark brown dorsally, each segment pale terminally; slightly pale ventrally.
Male genitalia (Fig. 5G, H). Valva gradually narrowed and bearing dense long setae distally; costa arched near base and accompanied by a cluster of short and curved setae; sacculus gradually narrowed to apex, with a cluster of long setae near middle. Posterior phallus inflated slightly, with three long leaf-like cornuti tapered apically.
Etymology. The specific name is derived from the Latin ternifolius (meaning 'trifoliate'), in reference to three long leaf-like cornuti.
Distribution. China (Yunnan). Remark. Coremata of some male individuals of this species were protruded out of the body, forming a cluster of white hairs at the end of the abdomen.

Discussion
The species in the present study, represented by B. megesalis, have a broad valva, whose costa is arched near the base or middle and accompanied by a cluster of long curved setae. The cornuti of the phallus of these species are diverse and therefore useful for interspecific identification. Seizmair (2021) divided Bradina into seven groups according to wing pattern characteristics, such as forewing and hindwing of the same color or of different colors, and whether the postmedial line is absent or present, and in the latter case whether it is straight or curved. In our opinion, however, it is difficult to divide the genus based only on wing pattern and color, and it would be more convincing to divide it by combining the appearance and morphology of the genitalia. In addition, most species of the B. diagonalis group in Seizmair's study are similar to the species in the present study both in appearance and genitalia. However, we found that B. diagonalis, as representative species of the B. diagonalis group, is different from most other species of this group in wing venation and genitalia. Therefore, further study on more species globally and in more detail is needed to clarify this confusion. In addition, the transverse crescent signum of Bradina is a distinctive feature. Like Bradina, the Steniini genera Diathrausta and Perisyntrocha also have an arched, transverse signum in the female genitalia's corpus bursae (Mally et al. 2019). This could indicate an evolutionary relatedness of these three genera, which is expected to be addressed in the future research.