Long Jawed Orb Weavers

Available online at www.worldscientificnews.com WSN 55 (2016) 210-239 EISSN 2392-2192 Rice Land inhabiting Long Jawed Orb Weavers, Tetragnatha Latreille, 1804 (Tetragnathidae: Araneae) of South 24-Parganas, West Bengal, India Debarshi Basu* and Dinendra Raychaudhuri** Department of Agricultural Biotechnology, Faculty Centre of Integrated Rural Development and Management, Ramakrishna Mission Vivekananda University, Ramakrishna Mission Ashrama, Narendrapur, Kolkata – 700 103, India *,**E-mail address: dbasumk@gmail.com , dinendrarccu@gmail.com ABSTRACT Spiders inhabiting rice land ecosystem demand serious consideration primarily due their predatory efficiency In India, their role as a potential bio-control agent is yet to be evaluated The coastal ecosystem in the Gangetic Delta at the southern part of West Bengal, India, exhibits a wide variety of predatory spider population because of climatic fluctuation, soil quality and several other factors Orb-weaving spiders appear to be of special importance as they trap more than what they actually consume The present study is aimed at unfolding the taxonomic diversity of Tetragnatha Latreille, 1804 (family Tetragnathidae, Menge, 1866) which is probably the mostly predominant group amongst orb-weavers found in rice fields of South 24 Parganas, West Bengal, India Of the seven tetragnathid species recorded from the study area, three, T chauliodus (Thorell), T boydi O P Cambridge, and T josephi Okuma are found to be new from the country The referred species are therefore described and illustrated Further a key to the species occurring in the area has also been provided Keywords: Spiders; Orb-weavers; Tetragnatha; South 24 Parganas; India World Scientific News 55 (2016) 210-239 INTRODUCTION Predatory importance of spiders inhabiting cultivated fields is controversial The results of some European studies indicate that the foliage-dwelling spiders of cultivated fields, because of their low population densities, are of minor importance as predators of insects Other European studies show, that the ground-dwelling spiders of cultivated fields are concerning their abundance, a dominant predator group, that significance as control agents still is largely unknown up to the present In rice fields (swamp ecosystems) in Asia, receiving little or no pesticides, as well as in European and American swamp ecosystems, spiders may be an important predator group In South Africa spiders were used successfully as biological control agents against flies (Nyffeler and Benz, 1987) It is unfortunate that in Indian context the role of spiders as a potential bio-control agent is yet to be evaluated properly Except a few data generated in KeralaandTamil Nadu, India, (Sebastian and Chacko,1994) and some scattered information from a few parts of this country (Chelliah, Bentur and Prakasa Rao, 1989, Gupta and Pawar, 1982, Rajendra, 1987, Banerjiet al 1993, Ganesh Kumar, 1994, Pathak and Saha, 1999), no significant report has reached us so far Apart from the extensive study on the predatory spiders in tea ecosystem of Dooars (Roy, 2013), an area at the foot hill of Eastern Himalaya, no significant contribution is available from the eastern region of India, especially West Bengal However, Satpathi (2004) did emphasise the predatory potential of spiders Success of integrating spiders in the IPM programme in any crop system largely depends on the data generated on their diversity, distribution, ecology, biology, predatory efficiency and many more The present study therefore, is aimed at unfolding the taxonomic diversity of spiders inhabiting riceland ecosystem with special reference to Gangetic Delta It won’t be out of place to refer the contribution of Majumder (2007) who did bring out a pictorial handbook on the spiders of Suderbans, South 24- Parganas Interestingly, the coastal ecosystem in the Gangetic Delta at the southern part of West Bengal exhibits a wide range of species population Climatic fluctuation and variation in soil quality induce fascinating cultural practices in this belt resulting a tremendously diverse pest upsurge at different point of time Further, it is observed that the diversity of spidersso far encountered in this shore of Bay of Bengal shows an affinity with those of Philippines and Taiwan, which are at the other end of the Bay Role of orb-weaving spiders should be thoroughly worked out particularly when members of this group build large webs at times Expectedly such webs would trap more number of preys than what the spiders would actually consume.Typical orb weavers necessarily include members of the long-jawed orb weavers exclusively belonging to the family Tetragnathidae Menge, 1866, composed of 48 genera and 344 species till date (World Spider Catalog, 2016) Significant contributors on Tetragnatha Latreille, 1804 are Okuma (1987, 1988), Barrion and Litsinger (1995), Gillespie (1987, 1991, 1992, 1993, 1994), Gillespie et al (1997), Gillespie (2002), Dimitrov and Hormigera (2009) and Jayakumarand Sankari (2010) Genus Tetragnatha Latreille, 1804under the family Tetragnathidae Menge, 1866 especially comes under focus in our current endeavour though many others are of equal importance in the same context Our effort so far helped record of seven speciesfromthe rice land ecosystem of South 24 Parganas, a district located at Gangetic Delta of West Bengal Of -211- World Scientific News 55 (2016) 210-239 those, T chauliodus (Thorell) T boydi, O P - Cambridge, 1898 and T josephi Okuma, 1988, are found to be new records from India and accordingly described and suitably illustrated supplemented by digital images They are found to construct large horizontal web spread over the entire section of paddy fields It thus appears that TetragnathaLatreille,1804 may be aproficient candidate of biological control, not only by devouring the prey but also by trapping more no of prey insects in their web Following discourse is on the taxonomy of the Tetragnatha Latreillespecies recorded from the study area STUDY AREA: (vide map) Site 1: Narendrapur Site: Sarisha Site 2: Arapanch Site 6: Kakdwip Site : NImpith Site 7: Gosaba Site 4: Manasadwip South 24 Parganas (22.1352° N, 88.4016° E), a district of West Bengal, belongs to the large delta of the Gangetic plain Seven discrete areas, from six different blocks are selected as fields of study Fields in different locations are identified in such a way that they represent the spider faunal diversity of the district as a whole Of them, three study areas are located at three different regions of Sundarban, a heritage site recognised by UNESCO in (1997 for its mangrove vegetation where due to the proximity of Bay of Bengal, salinity and nutrient structure of soil vary to a considerable extent affecting the growth and distribution pattern of the agro-ecosystems The study areas are as follows – Narendrapur [NPUR] (Block Sonarpur) (22.4391°N and 88.3968°E), Arapanch [ARPH] (Block - Sonarpur) (22.4491°N and 88.3915°E), Sarisha [SRSH] (Block - Diamond Harbour) (22.1987°N and 88.2023°E), Manasadwip [MSDP] (Block - Sagar) (21.753° N and 88.106°E.), Nimpith [NMPT] -212- World Scientific News 55 (2016) 210-239 (Block - Jaynagar II) (22.1772°N and 88.4258°E), Kakdwip [KKDP] (Block –Kakdwip) (21.8760°N and 88.1853°E), Gosaba [GSBA] (Block - Gosaba) (22.1652°N and 88.8079°E) Site 1: Narendrapur Site 2: Arapanch -213- World Scientific News 55 (2016) 210-239 Site 3: Sarisha Site 4: Manasadwip -214- World Scientific News 55 (2016) 210-239 Site 5: Nimpith Site 6: Kakdwip -215- World Scientific News 55 (2016) 210-239 Site 7: Gosaba Time of study Field visits were carried out in every month of any calendar year during the crop seasons It was continued form October, 2013 to November, 2015 The annual rainfall (average) in the district was 1796 mm Temperature in the study areas varied from 10 °C to 35 °C during course of study MATERIALS & METHODS For collection of spiders, sweep nets, bush beating and collection in inverted umbrella, hand picking techniques were used Several pit fall traps were laid in the collection localities to trap ground dwelling spiders Samples after collection [collector: D Basu] were preserved in 70% alcohol and later transferred to glass vials filled with Audman’s fixative Necessary labels were used to mark each of the samples Data regarding locality, date of collection, collector’s name were noted in a note book in the field itself The samples were studied under Sterozoom Binocular Microscopes Olympus SZX 10 and SZX 16 Line drawings were made with the aid of necessary accessories attached to the microscopes.Photographs were taken by a digital camera attached to the microscopes All measurements are in millimetres, made with an eye piece graticule -216- World Scientific News 55 (2016) 210-239 Abbreviations use TL: Total length, CL: cephalothorax length, CW: cephalothorax width, AL: abdominal length, AW: abdominal width,AME: Anterior median eye, ALE: Anterior lateral eye, PME: Posterior median eye, PLE: Posterior lateral eye Deposition All materials are in the collection of Department of Agricultural Biotechnology, IRDM Faculty Centre, RKM Vivekananda University, Narendrapur TAXONOMY Members of the family Tetragnathidae Menge, 1866 have long legs and body, except in the genus Dyschiriognatha, with rounded abdomen; eyes in two rows, may be parallel or convergent but lateral eyes never contiguous; chelicerae well-developed, long, often directed forward and diverging, with well-developed teeth; labium prominently rebordered; femora with a series of trichobothria dorsally close to base; auxilliary foot claws present except in Pachygnatha; and abdomen with or without pattern Male pedipalp relatively simple, prominent and hairy; paracymbium emanates from base of tarsus Epigynum reduced, epigastric fold strongly procurved and the genital orifice occur posterior behind tobranchialopercula Two genera of Tetragnathids – Tetragnatha P.A Latreille, 1804 and Dyschiriognatha Simon, 1893 – are very common in the Philippine ricefields and throughout South and Southeast Asia (Barrion and Listinger, 1995) Genus: Tetragnatha Latreille, 1804 Tetragnatha Latreille, 1804 Nouv Dct d’Hist Nat 24: 135 Diagnosis: Body prominently long and narrow, several times longer than wide; carapace oval, widest near the middle, flattened above, with a conspicuous thoracic groove; two eye rows either parallel or convergent or divergent, lateral eyes never contiguous, each eye surrounded by a black ring; chelicerae well developed, especially in males, and margins of fang furrow provided with numerous teeth; in males a strong projecting clasping spur may or may not be bifid at its tip; maxillae parallel, long, and dilated at distal ends; abdomen at least twice as long as wide, in females often swollen at base; often base slightly bifid and overhangs cephalothorax; epigynal slit posterior to lung slits in the procurved epigastric furrow; spinnerets usually terminal or almost so; legs and palpi very long and thin, but proportions differ in various species (Barrion and Listinger, 1995) Type species: Tetragnatha striata L Koch, 1862 Distribution: The genus is widespread throughout the world andcommon in wetland environments Key to species Spinnerets situated at or near the middle of the abdomen; abdomen outwardly produced, nearly at 1/3 length following which produced narrowly and inwardly; posteriorrow of eyes -217- World Scientific News 55 (2016) 210-239 produced, much narrower than the anterior row;pro and retro margins of the chelicerae with and teeth respectively; genital fold short, broad, apical marginincurved ……………………………………… javana (Thorell, 1890) - Spinnerets not situated at or near the middle of the abdomen;abdomen more or less parallel sided, neither outwardly produced, nor produced narrowly as well as inwardly; both rows of eyes of similar length………………………… 2 Genital fold long , incurved near base…… - Genital fold short, broadly U or V shaped …… .5 Pro and retromargins of chelicerae with 12 & teeth respectively; posterior row of eyes wider than anterior row; fang 1/5 shorter than cheliceral length ……………………………………………… chauliodus (Thorell, 1890) - Pro and retromargins of chelicerae with 11 & teeth respectively; both rows of eyes are of equal length………………………………… 4 Sternum distally acutely produced; cheliceral distal tip devoid of tooth; fang without tooth; posterior row of eyes nearly in a line while anterior row procurved; genital fold distally swollen; apical margin concave maxillosa Thorell, 1895 - Sternum distally broadly produced; cheliceral tip with long, strong, incurved teeth; fang near base with a strong tooth; both rows of eye procurved; genital fold not so swollen, distally wide, apical margin straight…… .boydi O Pickard-Cambridge, 1898 Genital fold twice wider than long, chelicerae broad, pro and retromarginswith7 & teeth respectively; sternum cordate …… josephi Okuma, 1988 - Genital fold short and broad; sternum elongate, cylindrical 6 Chelicerae long, cylindrical, fang nearly as long as/longer than the chelicerae; pro and retromargins with 12 & 13 teeth respectively; sternum distally produced, basally constricted, apically bifid; outer margin of maxilla incurved near middle and outwardly directed ……………………………………… hasselti Thorell, 1890 - Chelicerae broad and short, fang nearly half of cheliceral length; each of pro and retromarginswith 12 teeth; sternum bluntly produced, not basally constricted, outer margin of maxilla nearly straight …………ceylonica O Pickard-Cambridge, 1869 Tetragnatha javana (Thorell, 1890) (Figs: 1-5, plate - 1: 36-39) Eucta javana Thorell, 1890 Ann Mus Civ Genova 28: 236 Measurements (female): CL – 2.64, CW – 0.15, AL – 1.34, AW –0.20, TL – 3.98 -218- World Scientific News 55 (2016) 210-239 Inter-ocular distance: AME – AME = 0.12, ALE – AME = 0.16, ALE – ALE = 0.72, PME – PME = 0.12, PLE – PME = 0.20, PLE – PLE = 0.56 , ALE – PLE = 0.20, AME – PME = 0.24 Legs: I 15.00 (6.0, 1.16, 6.50, 6.67, 1.34) II 12.92 (3.8, 0.85, 3.42, 4.00, 0.85) III 6.20 (2.00, 0.55, 1.40, 1.70, 0.60) IV 13.29 (4.72, 0.58, 3.43, 3.71, 0.85) Leg formula 1243 Material Examined: 12♀♀, MSDP, 16.X 2013, 10♀♀, GSBA, 10.X 2013, 9♀♀, ARPH, 16.X.2013, 16♀♀, NPUR, 18.X 2013, 14♀♀, KKDP, 17.XI.2013, 6♀♀, SRSH, 13 XI 2013, 8♀♀, NMPT, 16.XI 2013, 13♀♀, MSDP, 23.III 2014, 22♀♀, GSBA, 08.III.2014, 11♀♀, ARPH, 22.III.2014, 24♀♀, NPUR, 28.II 2014, 16♀♀, KKDP, 20.II.2014, 28♀♀, SRSH, 26.III.2014, 12♀♀, NMPT, 29.III.2014, 25♀♀, MSDP, 12.X 2014, 28♀♀, GSBA, 16.X.2014, 8♀♀, ARPH, 23.X.2014, 19♀♀, NPUR, 28.II 2014, 12♀♀, KKDP, 20.II.2014, 8♀♀, SRSH, 26.III.2014, 12♀♀, NMPT, 29.III.2014, 16♀♀, MSDP, 20.III 2015, 16♀♀,GSBA, 22.III.2015, 6♀♀, ARPH, 18.III.2015, 8♀♀, NPUR, 17.III 2015, 6♀♀, KKDP, 19.III.2015, 16♀♀, SRSH, 26.III.2015, 5♀♀, NMPT, 27.III.2015, 16♀♀, MSDP, 19.X 2015, 16♀♀, GSBA, 22.X.2015, 6♀♀, ARPH, 16.X.2015, 8♀♀, NPUR, 05.X 2015, 6♀♀, KKDP, 27.X.2015, 16♀♀, SRSH, 26.X.2015, 5♀♀, NMPT, 22.X.2015 Distribution: India: Bihar, Karnataka, Orissa, Tamil Nadu, West Bengal; Africa to Japan, Philippines, Indonesia, Nepal, New Guinea, South & South – East Asia (Okuma, 1988; Biswas & Biswas, 1992; Barrion & Listinger, 1995; Sebastian & Peter, 2009; Sen et al., 2009; Roy, 2013; World Spider Catalog, 2016) Tetragnatha chauliodus (Thorell, 1890) (Fig – 6-10, plate – 2: 40-44) Limoxere chauliodus Thorell, 1890 Ann Mus Civ Genova 30: 292 Measurements (female): CL - 3, CW – 2.16,AL – 7.84, AW – 2.23, TL – 10.84 Cephalothorax (Fig 6, plate 2: 40) yellowish brown, elongate, oval, cephalic area parallel sided, raised, wider than long (Fig 6, plate: 40), thoracic area wider, fovea deeply grooved, radii distinct Eyes 8, transparent, basally ringed with black, dissimilar, arranged in procurved rows, posterior row nearly straight, anterolaterals smallest, posteromedian largest, ocular quad longer than wide, anteriorly narrowed Eye diameter: Inter-ocular distance: AME – AME = 0.16, ALE – AME = 0.24, ALE – ALE = 0.92, PME – PME = 0.32, PLE – PME = 0.24, PLE – PLE = 0.80, ALE – PLE = 0.16, AME – PME = 0.20 Clypeus height very small Chelicerae (Fig 7, plate – 2: 41) yellow, long, promargin and retromargin with 11and 10 small teeth respectively, fangs dark brown, very long, stout, strongly curved, toothed at basal one third -219- World Scientific News 55 (2016) 210-239 [17] Pathak, S & Saha, N.N 1999 Spider fauna of rice ecosystem in Barak valley zone of Assam Ind J Entomol, 2: 211 [18] Rajendra, R 1987 Studies on the predatory spiders in rice ecosystem Ph D Thesis, TNAU 160 pp [19] Roy, T.K 2013 Spiders (Araneae: Arachnida) of Tea Ecosystem of Dooars, West Bengal PhD Thesis, CU 253 pp [20] Satpathi, C.R 2004 Predacious spiders of crop pests Capital Publishing Co., New Delhi, 1: 88-96 [21] Schoenly, K.G., Justo, H.D., Barrion, A.T., Harris, M.K & Bottrell, G.D.1998 Analysis of invertebrate biodiversity in Philippines farmers irrigated rice field Environ Entomol 27: 1125-1136 [22] Sebastian, P.A & Chacko, E 1994 Studies on the predatory spiders of paddy field from Kuttanad Proc 6th Kerala Sci Cong, 1: 377 [23] Sen, S 2010 Spiders (Araneae: Arachnida) of Gorumara National Park, Chapramari Wildlife Sanctuary and Mahananda Wildlife Sanctuary Ph D Thesis, CU 229 pp ( Received 02 September 2016; accepted 18 September 2016 ) -225- World Scientific News 55 (2016) 210-239 -226- World Scientific News 55 (2016) 210-239 -227- World Scientific News 55 (2016) 210-239 -228- World Scientific News 55 (2016) 210-239 -229- World Scientific News 55 (2016) 210-239 -230- World Scientific News 55 (2016) 210-239 -231- World Scientific News 55 (2016) 210-239 -232- World Scientific News 55 (2016) 210-239 -233- World Scientific News 55 (2016) 210-239 -234- World Scientific News 55 (2016) 210-239 -235- World Scientific News 55 (2016) 210-239 -236- World Scientific News 55 (2016) 210-239 -237- World Scientific News 55 (2016) 210-239 -238- World Scientific News 55 (2016) 210-239 -239- ... than what the spiders would actually consume.Typical orb weavers necessarily include members of the long- jawed orb weavers exclusively belonging to the family Tetragnathidae Menge, 1866, composed... TNAU: 183 pp [8] Gillespie, R.G 1987 The mechanism of habitat selection in long- jawed orb- weaving spider Tetragnatha elongata (Araneae, Tetragnathidae) Arachnol, 15: 81-90 [9] Gillespie, R G.,... respectively, fangs dark brown, moderately long, curved Maxillae (Fig 23 plate – 5: 56) yellow, longer, apically and laterally strongly scopulate Labium yellow, weekly longer than wide, medially constricted,