New record of scarab species, Adoretus testaceus (Hope) (Coleoptera: Scarabaeidae: Rutelinae) from Rajasthan, India Padala Vinod Kumar and Kolla Sreedevi* Division of Entomology, ICAR-Indian Agricultural Research Institute, Pusa campus, New Delhi 110 012, India *E-mail:kolla.sreedevi@gmail.com ABSTRACT Scarabaeidae is one of the largest families of Coleoptera that comprises of white and root grubs. Explorations of scarab species diversity in Rajasthan, India revealed a ruteline species, Adoretus testaceus (Hope), which is a new report to the region thus adding a new distributional record to the species. The sole report of the occurrence of this species in India was from Darjeeling dt., West Bengal. The detailed descriptions of A. testaceus along with the distributional records in India are furnished. KEY WORDS: Adoretus testaceus, Rutelinae, Scarabaeidae, morphological description INTRODUCTION Scarabaeoidea of Coleoptera is one of the largest superfamilies that comprises of approximately 31,000 species occurring worldwide. It includes three major families, viz., Lucanidae, Passalidae and Scarabaeidae (Ritcher, 1966), of which the family Scarabaeidae is largest and comprises of about 91% of Scarabaeoidea represented by 27,800 species worldwide (Ratcliffe and Jameson, 2004) and 2500 species in India (Ali, 2001). Scarabaeidae in turn consists of coprophagous and phytophagous groups. The explorations of scarabaeidae fauna in the vicinity of groundnut ecosystem in Rajasthan yielded a ruteline species, Adoretus testaceus (Hope, 1831), which is reported here as new record to Rajasthan along with brief description of the species. MATERIALS AND METHODS Surveys were conducted during April - August, 2015 in Rajasthan, India for white grub species associated with groundnut ecosystem. The scarab species were collected from Dausa, Tonk and Jaipur districts of Rajasthan, India Collection of adult beetles was made during the night by using light traps with black and mercury light sources. Since the beetles settle on the leaves of nearby avenue trees for feeding and mating after emergence, adults were also collected from the nearby host trees by scouting using the powerful light torches. Generally white grub www.currentbiotica.com 208
adults emerge from soil after the first shower of monsoon and it is continued up to August. Hence, the collection of adults was done during the months of April - August, 2015 at fortnightly intervals in the selected locations of the survey areas. The beetles attracted towards the light source were trapped in the collection bucket, placed beneath the light source that contain cotton swab sprinkled with ethyl acetate. Light traps were operated from 6:30 to 10:00 pm. The beetles trapped in the collection bucket were sorted out and transferred to small insect boxes for further processing. Processing of specimens Collected specimens were sorted out to remove damaged specimens and then sorted specimens were subjected to little warm water at 60 C temperature in Sonicator for 5 minutes, there after cleaned with camel hair brush to remove soil particles adhered to the body of the specimens. The specimens then were washed with water mixed with mild soap solution and then thoroughly rinsed with clean water. After cleaning, the specimens were kept for relaxation overnight in relaxation boxes. Next day morning, the specimens were pinned, stretched, labeled and placed in hot air oven at temperature about 600 C for proper drying. Naphthalene balls were also pinned at the corners of insect box to avoid attack of museum insects. Finally the specimens were identified up to species level with available keys (Brenske, 1899; Arrow, 1910, 1917; Khan, 1975). Line drawings and documentation of morphological characters The stereozoom microscope Leica EZ24 HD was used to study the different morphological characters including genitalia of the species. Drawing tube attached to a WILD HEERBRUGG TYPE 308700 stereo zoom microscope was used to draw the line diagrams. The specimens were observed for the distinctive colour patterns. Colour of clypeus, frons, pronotum, scutellum and elytra were observed carefully for the shiny or dull nature. The images of all the diagnostic characters were made by Leica EZ24 HD. Male genitalia extraction The abdomen of the male specimen was gently detached from the body and placed in 10% potassium hydroxide (KOH) solution for few hours for softening of the tissues. Later, the genitalia were extracted by using forceps. Then abdomen was glued back to the body. The genitalia were again kept in 10% KOH solution for 4-5 hours to soften heavily sclerotized portion. The characters were documented and images were taken by by Leica EZ24 HD stereozoom microscope. After study, genitalia were placed in genitalia vials containing glycerol, labelled and pinned along with the specimen for future use. RESULTS AND DISCUSSION The species, Adoretus testaceus (Hope) was identified based on keys of Arrow and descriptions are given hereunder. Adoretus testaceus (Hope, 1831) Geniates testaceus Hope, 1831, Gray s Zool. Miscell., p. 23. Geniates assimilis Hope (new syn.) Adoretus testaceus Arrow, 1917. Fauna Brit. India (Coleoptera: Lamellicomia), 2: 320. www.currentbiotica.com 209
Material examined: INDIA: Rajasthan: Jaipur (26 54'00.40'' N, 75 47'59.36'' E), 3 10.vi.2015, Coll. P. Vinod. Male: Body elongated, small sized measuring 10.5 mm length, 6 mm breadth (Fig. 2), head dark brown colour, elytra little paler, antenna, femur, tibia yellow in colour. The head and sides of the body covered with grey setae and the pronotum bear irregular patches of similar setae (Fig. 1D & 2e). Elytra with very minute setae, more at sides, towards extremity of elytra with three rows of erect setae. Head: Length 1.85 mm, breadth 2.9 mm, finely granulated and broad, clypeus broadly rounded, and strongly reflexed in the middle, lateral sides and front angles are rounded (Fig 1B & 2c), punctations deep and fine, front margin slightly raised, setae irregular. Fronto-clypeal suture distinct, frons with shallow punctations and grey setae. Antenna ten segmented with three segmented club, slightly shorter than the funicular segments (Fig. 1.F & 2d). Compound eyes rounded. Labrum produced downward. Maxillary palpi four segmented with rounded apex. Thorax: Pronotum length 1.5 mm, breadth 3.5 mm, lateral margins rounded, with grey setae, anterior angles acute, posterior angles obtuse, front margin slightly curved at middle with row of setae, hind margin reflexed with row of setae, shiny, closely, uneven medium deep punctations, grey coloured setae sparsely at midline dense at sides (Fig 1D). Scutellum broad at anterior, narrowed towards posterior with dense punctures and setae (Fig 1C). Elytra costate with distinct, deep, dense punctations grey setae. Front tibia armed with three sharp teeth with distinct serrations at base (Fig. 1G), two hind tibial spurs on one side of first tarsal segment (Fig. 1J), front and middle leg claws unequal, larger claw clefted, hind tarsal claws unequal not clefted. Male genitalia: Phallobase slightly broad at base, symmetrical parameres right angles to the phallobase, wider at base narrowed towards apex united medially with deep U shape notch at apex (Fig 1 K, L; Fig. 2a, b). Remarks: The species has been recorded from Nepal and Bhutan in South Asia by Arrow (1917). This species has been reported from West Bengal by Chatterjee and Biswas (1995) as first record from India. This is the first report from Rajasthan, India and the species differs from closely resembling species A. flavus in the character that two upper teeth of the front tibia not divided by an acute notch, where in A. testaceus, the two upper teeth of the front tibia divided by acute notch. The species also differs from A. versutus in possessing the serrations on basal part of fore tibia in addition to larger claw being distinctly clefted in fore and mid leg. In A. testaceus, the serrations are absent and fore and mid tarsal claw feebly clefted. Distribution: India: West Bengal, Rajasthan; Bhutan, Nepal (elsewhere). www.currentbiotica.com 210
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2 2a 2b 2c 2d 2e Fig. 2: Adoretus testaceus habitus; a Male genitalia, b Parameters of aedeagus, c- Clypeus and frons, d Antenna, e Pronotum CONCLUSION The scarab species, Adoretus testaceus (Hope) has been reported for the first time from Rajasthan, India. This species was earlier reported by Chatterjee and Biswas (1995) from Kurseong, Darjeeling dt., West Bengal collected in 1907, after which there are no documented reports of this species occurrence in India. After nearly a century, the species has been found in Rajasthan which throws a light on migration of the species from east to west. ACKNOWLEDGEMENTS: The senior author is grateful to ICAR-Indian Agricultural Research Institute (IARI), New Delhi for providing fellowship to carry out the post graduate research work. Thanks are also due to the Head and the Professor, Division of Entomology, ICAR-IARI for facilitating the work. www.currentbiotica.com 212
REFERENCES Ali, A. T. M. 2001. Biosystematics of phytophagous scarabaeidae an Indian overview. In: Indian phytophagous scarabs and their management. Present status and future strategies. Agrobios, India, 5-37. Arrow, G. J. 1917. The fauna of British India. Including Ceylon and Burma. Coleoptera, Lamellicornia Part 2 (Rutelinae: Desmonycinae and Euchirinae). Taylor and Francis, London, UK. Chatterjee, S. K. and Biswas, S. 1995. Coleotpera: Scarabaeiae: Cetoniinae, Dynastinae, Rutelinae. In State Fauna Series 3: Fauna of West Bengal, Part 6(A) (Insecta: Coleoptera). Published by The Director, Zoological Survey of India, Kolkata, 363 447. Ratcliffe, B. C. and Jameson, M. L. 2004. The revised classification for Scarabaeoidea: what the hell is going on. Scarabs, 15: 3-10. Ritcher, P. O. 1966. White grubs and their allies. A study of North American scarabaeoid larvae. Oregon State Monographs. Oregon State University Press, Cornvallis, USA. 8: 326-415. [MS received 18 August 2016; MS accepted 21 November 2016] Disclaimer: Statements, information, scientific names, spellings, inferences, products, style, etc. mentioned in Current Biotica are attributed to the authors and do in no way imply endorsement/concurrence by Current Biotica. Queries related to articles should be directed to authors and not to editorial board. www.currentbiotica.com 213