A Survey of the Genus Theretra Hubner, 1819 (Lepidoptera: Sphingidae) from Kodaikanal Hills (Western Ghats), Tamil Nadu, India

International Journal of Scientific Research in ______Research Paper . Biological Sciences Vol.6, Issue.1, pp.253-262, February (2019) E-ISSN: 2347-7520 DOI: https://doi.org/10.26438/ijsrbs/v6i1.253262

A Survey of the genus Theretra Hubner, 1819 (Lepidoptera: Sphingidae) from Kodaikanal Hills (Western Ghats), Tamil Nadu, India

Pratheesh Mathew1, Kuppusamy Sivasankaran2, Sekar Anand3, Savarimuthu Ignacimuthu4*

1234Entomology Research Institute, Loyola College Chennai, Chennai-600034, Tamil Nadu, India

* Corresponding author:[email protected] Tel.: +9144-28178348 Fax: +9144-28175566. Available online at: www.isroset.org Received: 12/Jan/2019, Accepted: 05/Feb/2019, Online: 28/Feb/2019 Abstract – Kodaikanal hill station with its natural beauty and climatic conditions have become a noteworthy tourist spot in South India over the years. The ideal environmental condition and rich floral diversity homes for diverse fauna in Kodaikanal. Sphingid diversity of Kodaikanal has not been reported in the past. Through this study, we report the diversity and study of the external and genital morphologies of the genus Theretra Hubner, 1819 from Kodaikanal hills for the first time. A total of seven species were reported during the study, namely Theretra alecto, T. clotho, T. gnoma, T. nessus, T. oldenlandiae, T. pallicosta and T. silhetensis. Images and genitalia of male and female adult specimens are illustrated for each species.

Key words: Moth, Lepidoptera, Sphingidae, Theretra, Genitalia, Biodiversity, Western Ghats.

I. INTRODUCTION species of hawk moths are reported from India. [2;3]. Theretra Hubner, 1819 is a genus of hawk moths belonging The economic importance of Sphingid moths are well to the tribe Macroglossini Harris, 1839 under the subfamily studied and reported as one of the important pollinators Macroglossinae Harris, 1839. The genus Theretra can be among the order Lepidoptera that benefits not only the recognized by their palpi with an apical tuft of scales on the natural ecosystem but also the agrarian environment [1]. second segment directed ventrally; apex of the first is Taxonomic studies employ not only the morphological densely and regularly scaled on the inner side, with a cavity characters of lepidopterous insects, but also the various at the apex on the outer side [4]. More than 60 species have anatomical characters as well. Study of genital morphology been recorded under this genus from different parts of the is the traditional method of lepidopteran taxonomy which is world till date. still being used by many taxonomists even after the emergence of molecular taxonomy. The male and female During the present study, seven species of sphingid moths genital characteristics are species specific to all the under the tribe Macroglossini Harris, 1839 of subfamily lepidopterans. These complementarity and specificity of Macroglossinae belonging to the genus Theretra were genital morphology prevent interspecific mating and also act collected, viz. Theretra alecto, T. clotho, T. gnoma, T. as an identifying species specific character for lepidopterists. nessus, T. oldenlandiae, T. pallicosta and T. silhetensis. The genus Theretra Hubner 1819 is distributed worldwide They are recorded for the first time in Kodaikanal hills. with more than 60 species. The genus has appeared in the results of very few diversity studies conducted for the family The systematic account of moths with genital morphology Sphingidae at different locations of India. belonging to the genus Theretra under the subfamily Macroglossini has not been published earlier from India. The Hawk moths or sphinx moths with their larvae known as systematic details given here thus contribute to the hornworms belong to the family Sphingidae Latreille, 1802 taxonomic information of Indian Lepidopterans. under the Superfamily Bombycoidea. There are more than 1500 species of Sphingid moths worldwide. About 204 Section I of this article contains the introduction to the Family Sphingidae and genus Theretra of the Superfamily

Bombycoidea. Section II explains the materials and methods Theretra alecto transcaspica O. Bang-Haas, 1927, employed for this study. Section III is provided with the Horae Macrolepidopt.Reg. palaearct. 1: 80. results of the detailed study of moth genitalia of seven Theretro alecto intermissa Gehlen, 1941, Ent. Z., species from the genus Theretra. The images of moth Frankf. a. Main 55: 185--186. specimens and diagrams of genitalia with description of genital characteristics are also presented. A dichotomous Material examined: Kodaikanal, 2 ♂, 9.III.2014; 1 ♂, taxonomic key for the genus Theretra based on male 25.X.2014; 1 ♂, 5.V.2015. genitalic characters is provided at the end. Section IV Diagnosis: Wingspan – 81mm. Head: Pale brown, two includes the discussion of results of the study. Section V lateral white lines running above the eyes up to the thorax on gives the conclusions from the research results and both sides. Antennae white. Palpi indistinct with long scales discussions. projecting over it. Thorax: Pale brown, lateral white lines II. MATERIALS AND METHODS continued on both sides from the head towards the abdomen. Abdomen: Pale brown slightly lighter than head and thorax; Moths belonging to the genus Theretra of subfamily prominent black mark on lateral sides at the base; tapering Macroglossinae were collected from January 2014 to and pointed towards anal region; single row of basitarsal January 2017 from four different sites in Kodaikanal. spines on the forelegs. Forewing: dorsal side beige ground Kodaikanal (10014‟6”N; 77029‟6”) is located above the color; dark speck at the end of cell; six oblique post medial southern escarpment of upper Palani Hills, between the lines running from apex towards inner margin; fifth Parappar and Gundar valleys with an altitude of 2,133 m postmedian line more prominent; second and fourth lines (6,998 ft) in the Dindigul district, Tamil Nadu, India. weak; Hindwings: deep pinkish, minutely variegated;, base Kodaikanal is spread on an area of 21.45km2 with an and dorsum strongly blackened and a diagnostic paler zone average temperature ranging from 110C to 200C. on the tornus.

The collection was carried out using mercury vapor lamp Male genitalia: Uncus short, stout and apically curved, with (160W) as the light source and a white cloth as the screen. hairs. Gnathos stout, curved and somewhat pointed. Moths were also collected using sweep nets and plastic Tegumen short and broad. Valve oval shaped, broad with containers and were identified using dichotomous keys of hairs exteriorly, harpe slender and curved.Valvae lobes Hampson (1894) and Bell and Scott (1937). This type of broad with a slender branch towards inner side. Vinculum collection method helps to avoid killing or damaging of short and nearly „V‟shaped; Juxta inversely triangular. previously collected, as well as undesired specimens Aedeagus long and broad with multidentate short structure [5].Many commercially available trap designs are not on the right apically, and on the left with an oblique row of suitable for tropical conditions due to their small size that minute teeth. (Fig. 1a, 1b) cannot accommodate enormous catches [6].The collected specimens were spread and pinned at the study area and Distribution: India, Pakistan, Iraq, Iran, Afghanistan, were carefully transported; these are laborious and time Uzbekistan, Kyrgyzstan, Greece, Bulgaria, Egypt, Lebanon, consuming process as reported by many lepidopterists [7]. Israel, Turkey, Turkmenistan. The collected specimens are deposited at the Museum of

Entomology Research Institute, Loyola College Chennai. 2 Theretra clotho (Drury, 1773) -- Common hunter III. RESULTS hawkmoth (Fig. 2) Sphinx clotho Drury, 1773, Illust. nat. Hist. exot. 1 Theretra alecto (Linnaeus, 1758) -- Levant Insects 2: index [91]. hawkmoth (Fig. 1) Chaerocampa bistrigata Butler, 1875, Proc. zool. Sphinx alecto Linnaeus, 1758, Syst. Nat. (Edn Soc. Lond. :249 10) 1: 492. Deilephila cyrene Westwood, 1847.Cabinet oneni. Sphinx cretica Boisduval, 1827, Annls Soc. linn. Ent;13, pi 6, f1 Paris 6: 118. Chaerocampa aspersata Kirby, 1877, Trans En Theretra freyeri Kirby. 1892, Synonymic Cat. Soc. Lond.:241 Lepid. Heterocera 1: 650.

Material examined: Kodaikanal, 1 ♂, 14.IX.2015; 2 ♂, postmedial line. Hindwing: broad non-uniform yellow band; 21.VI.2016. smoky black area at the base, gradually getting paler towards anal and outer margin yellowish white area below and above Diagnosis: Wingspan 85mm. Head: Greenish brown, a the black patch. white lateral stripe running from the palpus to the thorax on both sides. Antennae white. Thorax: Greenish brown ground Female genitalia: Ovipositor lobes well developed with color, lateral white stripe from the head continued to end of prominent long setae. Anterior and posterior apophysis well thorax. Legs white. Abdomen: Abdomen also greenish- developed; posterior apophysis slightly shorter than the brown, upperside with a pair of black lateral patches at base. anterior apophysis. Ductus bursae long and slender Corpus Forewing: upper side olive-green ground color, postmedian bursae spherical; with long; signum long slender, and well lines generally weak, except for the fourth, which is developed (Fig.3a) conspicuous and runs to the apex of the wing where it merges with the oblique apical line. Underside, blackish Distribution: India, Sri Lanka, Nepal, Burma, Thailand, brown basally. Hindwing: dorsal side with yellowish China. median band more shortened anteriorly and not reaching anterior of M3. 4 Theretra nessus (Drury, 1773) --Yam hawk moth Male genitalia: Uncus short apically hooked. Gnathos (Fig. 4) pointed with serrations on inner side. Tegumen somewhat Sphinx nessus Drury, 1773, Illust. nat. Hist. exot. broad. Valve broad and oval shaped with numerous hairs Insects 2: index [91]. interiorly. Valvae lobes nearly rectangular with pointed Sphinx equestris Fabricius, 1793, EnL sysL angles towards inner side. Harpe stout and with spiny 3(1):365 groove apically towards inner side. Juxta shield shaped. Chaerocampa nessus rubicundus (Schaufuss,1870), Vinculum long and „U‟ shaped. Aedeagus long and slender; Nunquam otiosus 1:18 apex sclerotized with proximally directed subapical digitate Material examined: Kodaikanal, 1♂, 13.VII.2015; 1 ♂, process. (Fig. 2a, 2b) 22.X.2016; 3 ♂, 27.XI.2016. Distribution: India, Pakistan, Sri Lanka, Nepal, Bhutan, Diagnosis: Wingspan 115 mm. Head: olive green, white Myanmar, China, Japan, Hong Kong, Indonesia. stripe from palpi running above the eyes on each side, 3 Theretra gnoma (Fabricius, 1775) -- Faintly- antennae white. Thorax: olive green suffused with marked hunter hawkmoth (Fig. 3) ferruginous, medial more greenish, lateral white stripe Sphinx gnoma Fabricius, 1775; Syst. Ent.: 546 continued from head to base of abdomen; Abdomen: Sphinx butus, Cramer. 1777,Uid. KapeUen underside golden, dorsal side with a broad green stripe down 2:88,152pp. centre of abdomen and golden yellow at sides. Fore wing: Chaerocampa gonograpta Butler. 1875, Proc. zool. olive-brown, costal margin with green band; a black speck at Soc. Lond.: 249. end of cell; a postmedial waved oblique line met by three straight oblique parallel lines from the apex meeting at inner Material examined: Kodaikanal, 1 ♀, 17.X.2014; 1 ♀, marginand continued as two submarginal lines. Hind wings: 19.VI.2016. black-brown; ochreous at anal angle, broad irregular yellow band inner to the dark inner margin, ochreous towards the Diagnosis: Wingspan 91 mm. Head: Pale ochreous brown, apex as a submarginal band; underside suffused with reddish antennae white, white streak running above eyes from base ochreous, black basal region. of palpi to the thorax on both sides; eyes prominent. Thorax: uniformly ochreous brown, white streak continued to end of Male genitalia: Uncus short and stout apically curved and thorax on sides. Abdomen: greenish brown, a black patch on with a row of numerous hairs at the base. Gnathos slightly either side of first segment; Underside more ochreous. spatulate, apically rounded. Tegumen short and broad. Forewing: a distinct black speck at end of cell, longer with Valvae broad, oval shaped, covered with hairs interiorly pointed apex, a large triangular black patch at base of wings; with four large medial spines. Valvae lobes rectangular with green coastal zone intercommunicate irregularly with anterior angle produced towards inner side. Harpe curved

© 2019, IJSRBS All Rights Reserved 255 Int. J. Sci. Res. in Biological Sciences Vol. 6(1), Feb 2019, ISSN: 2347-7520 and apically concave. Juxta rectangular, concave anteriorly Chaerocampa pallicosta Walker, 1856, List of and sclerotized between valvae. Vinculum short, broad and Specimens lepid. Insects Colln Br. Mus. 8: 145. „U‟ shaped. Aedeagus short and stout; the apical lobe spherical with multidentate process. (Fig.4a, 4b) Material examined: Kodaikanal, 1 ♂, 20.X.2014; 1 ♂, 7.VII.2015. Distribution: India, Sri Lanka, Burma, Nepal, Thailand, Vietnam, China, Japan, Hong Kong, Borneo, Java, Diagnosis: Wingspan 82 mm. Head: Chestnut-brown, Sunderland to Australia, New Caledonia. antennae white, a dorso-lateral white stripe from palpi to thorax on either side. Thorax: Chestnut-brown, a narrow 5 Theretra oldenlandiae (Fabricius, 1775) -- White- white dorsal line. Foreleg with paired spines at the distal end banded hunter hawkmoth (Fig. 5) of tibiae. Abdomen: tapering to posterior end in both male Sphinx oldenlandiae Fabricius, 1775, Syst. Ent.: and female, uniformly brownish chestnut. Forewing: 542. purplish-brown on upper side; costa with white highlight, Sphinx drancus Cramer, 1777, Uid Kapellen 2:56, small white discal spot; a paler white line on inner margin. pi 132 Hindwing: orange on upper side with darker and diffused Chaerocampa sobria Walker, 1856, List Spec. Lep. marginal band. Ins. Bnt. Mus. 8:148 Deilephila proxima Austaut, 1892, Naturaliste Male genitalia: Uncus short apically curved with hairs at (2)6:69 the base exteriorly. Gnathos apically round. Tegumen short Theretra oldenlandiae fuscata Gehlen, 1941, Ent and broad. Valve broad and nearly sole-shaped, apically Rundsch. 56:304 triangular; harpe flattened, long, slender, and apex pointed. Valvae lobes curved with anterior edge more produced. Material examined: Kodaikanal, 1 ♀, 19.X.2016. Juxta oval in shape. Vinculum much broad and „U‟ shaped. Aedeagus slightly curved, broad and elongated; anteriorly Diagnosis: Wingspan 65 mm. Head: earthen brown, pointed dentate processes on right and left. (Fig. 6a, 6b) greyish-white dorso-lateral stripe from the palpus to thorax and a broader streak of same color on dorsal side running to Distribution: India, Sri Lanka, Nepal, Bangladesh, thorax. Thorax: Color similar to head with broader lateral Myanmar, Hong Kong, Taiwan, Thailand, China. and dorsal stripes, the tegulae fringed with silver. Abdomen: greyish-brown abdomen with a double silvery dorsal line, and a lateral stripe obscurely ochreous. Forewing: greyish- 7 Theretra silhetensis (Walker, 1856) -- Brown- brown with several oblique bands from the inner margin to banded hunter hawkmoth (Fig. 7) the tip; whitish-brown central band edged above with silver; Chaerocampa silhetensis Walker, 1856, List Spec. a dark brown band below and costal area greyish-brown, Lepid. Insects Colln Br. Mus. 8: 143. more whitish at the base, separated by a dark brown band. Chaerocampa[sic] bisecta Moore, 1857; in Hindwing: upperside blackish-brown having a paler brown Horsfield & Moore, Cat. lep. Ins. Mus. East India submarginal band of variable shade and distinctness. Coy 1: 278, pl. 11, f. 5, 5a

Female Genitalia: Ovipositor lobes inferior with long setae. Material examined: Kodaikanal, 1 ♂, 23.VI.2015. Anterior and posterior apophyses well developed; anterior Diagnosis: Wingspan 70 mm. Head: earth brown, whitish apophysis much longer than the posterior apophysis, Ductus grey stripe on dorso-lateral side from palpi to thorax, bursae broad and moderately long, Corpus bursae elliptical broader streak on dorsal side reaching thorax. Thorax: in shape, elongated longitudinally; signum long and slender. ochreous, broader dorso-lateral white stripe, legs whitish (Fig. 5a) externally. Abdomen: greyish brown, single median dorsal Distribution: India, Sri Lanka, Nepal, China, Thailand, silver lining, dorso-lateral ochreous streak. Forewing: pale Borneo, Hong Kong, Egypt, Philippines, Java. greyish-brown with oblique bands, silvery area between third and fourth postmedial lines, fourth and fifth lines 6 Theretra pallicosta (Walker, 1856) -- White- broader and beige. Hindwing: upper side pale blackish edged hunter hawkmoth (Fig. 6) brown, broad paler brown sub marginal line.

Male genitalia: Uncus somewhat long, slender and apically nessus having about 20 large hairs. Harpe showed the round. Gnathos short apically round. Tegumen short and greatest variation among these species. Harpe is slender, broad. Valve long, nearly sole-shaped and apically rounded. weakly sigmoid and apically conical in T. alecto, flattened, Valvae lobes nearly triangular. Harpe long, slender and long, slender and apex rounded in T. pallicosta, and truncate, curved. Juxta triangular with anterior edge slightly spherical. dorsal edge more or less notched in T. clotho. Vinculum much broad and „U‟ shaped. Aedeagus long and broad with multi-dentate process on the posterior end The aedeagus is the most easily identifiable species specific extending to either side. (Fig. 7a, 7b) genital structure among most of the Sphingidae group. Genus Theretra showed great degree of variation among Distribution: India, Sri Lanka, Nepal, China, Bangladesh, morphology of aedeagus. All the aedeagus of the species Thailand, Vietnam, Malaysia, Indonesia, Taiwan, Japan, discussed above have got a series of terminal dentate process Australia. which varied in number and order among the species. The dentate process extended to both left and right direction; Key to species for the genus Theretra gradually decreased in size towards extremity and was asymmetrical in the case of T. alecto and T. pallicosta. The genitalia study showed much observable variations among the male genitalial features. Based on the different Out of the seven species, T.gnoma, and T. oldenlandiae were species specific characters observed during the genitalia studied only with female specimens. These two species study, a key is presented below for species segregation. could be differentiated by the shape of corpus bursae and signum. Corpus bursae of T. gnoma is more globular than T. Key to species based on male genitalic characters oldenlandiae which has an ovoid shape and the signum of 1. Uncus long……………………..…….……T. silhetensis former was shorter than the latter. Also, the ductus bursae of Uncus short………………………………….………....2 T. oldenlandiae was shorter than T. gnoma. Anterior and 2. Tegumen short and broad……………….…..…T. nessus posterior apophyses are well developed in both species and Tegumen long…………………...... …..……….………3 varying in length. However, apophyses of T. gnoma are 3. Valvae broad and sole shaped…….….……….……….4 having same length while anterior apophysis is longer than Valvae long and slender……………...……..…T. clotho posterior in T. oldenlandiae. 4. Vinculum „V‟ shaped and slender; multidentate process V. CONCLUSION on edge of aedeagus...... T. alecto Vinculum „U‟ shaped and aedeagus slightly curved…… The present study showed the variation of genital ……...……………………………………..T. silhetensis morphology among the seven species of the genus Theretra, proving the classical method of genital study as reliable tool IV. DISCUSSION for species identification for this genus. The diversity of the genus Theretra during the present study is promising for Genus Theretra from the subfamily Macroglossinae was further studies at the study area. Future comprehensive represented by seven species during the present study. All studies will help to reveal the Sphingid diversity of the seven species are first report to the study area. Genitalia Kodaikanal and to initiate conservation measures. study helped to confirm the species identification. Conflict of Interest. Though most of the male genitalia appeared similar in appearance being from same genus, the uncus and features The authors declare that there is no conflict of interest. of the aedeagus showed great observable variations. The uncus of T. clotho, T. nessus, and T. pallicosta are sinuate Acknowledgements while that of T. alecto is concavely upturned and of T. silhetensis is hardly curved. The gnathos is curved and We thank Entomology Research Institute, Loyola College pointed in T. alecto, T. clotho and T. pallicosta while it is Chennai, Tamil Nadu, India, for the financial support and slightly spatulate, apically rounded in T. nessus and dorsally lab facility for the present study. ribbed along edges and bisinuate in T. silhetensis. In all the REFERENCES species the valvae has numerous stridulatory scales with T.

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Fig 1 - Theretra alecto, Fig 1a – Male genitalia Fig 1b – Aedeagus

Fig 2 - Theretra clotho Fig 2a – Male genitalia Fig 2b – Aedeagus

Fig 3 - Theretra gnoma Fig 3a – Female genitalia

Fig 4 - Theretra nessus Fig 4a – Male genitalia Fig 4b – Aedeagus

Fig 5 - Theretra oldenlandiae Fig 5a – Female genitalia

Fig 6 - Theretra pallicosta Fig 6a – Male genitalia Fig 6b – Aedeagus.

Fig 7 - Theretra silhetensis Fig 7a – Male genitalia Fig 7b – Aedeagus.

Author’s Profile 1. Pratheesh Mathew (First author) Research Scholar Entomology Research Institute Loyola College Chennai Tamil Nadu – 600 034 India

2. Kuppusamy Sivasankaran (Second author) Scientist Entomology Research Institute Loyola College Chennai Tamil Nadu – 600 034, India

3. Sekar Anand (Third author) Research Scholar Entomology Research Institute Loyola College Chennai Tamil Nadu – 600 034, India

4. Savarimuthu Ignacimuthu (Fourth and corresponding author) Emeritus Scientist Entomology Research Institute Loyola College Chennai Tamil Nadu – 600 034 India