Present communication deals with redescription of the insect parasitic nematode, Steinernema scapterisci Nguyen and Smart, 1990, collected from the mole cricket, Gryllotalpa africana at Khurja, district (U.P.). The original description suffers from some morphological variations in the testis, tail and vulvular region

Chaudhary, Anshu

Malti, Malti

Singh, H. S.

Singh, Neetu

Journal of Applied and Natural Science

219Redescription of Steinernema scapterisci Nguyen and Smart, 1990:(Steinernematidae)H. S. Singh*, Malti, Neetu Singh and Anshu ChaudharyDepartment of Zoology, Ch. C. S. University, Meerut- 2500 04 (U.P.), INDIA*Corresponding author. Email : hirdaya_singh@ rediffmail.comAbstract: Present communication deals with redescription of the insect parasitic nematode, Steinernema scapterisciNguyen and Smart, 1990, collected from the mole cricket, Gryllotalpa africana at  Khurja, district (U.P.). The originaldescription suffers from some morphological variations in the testis, tail and vulvular region.Keywords: Entomopathogenic nematodes, Steinernema scapterisci, Gryllotalpa africana, TaxonomyISSN : 0974-9411 All Rights Reserved © Applied and Natural Science Foundation. www.ansfoundation.orgJournal of Applied and Natural Science 2 (2): 219-224 (2010)  JANSINTRODUCTIONEntomopathogenic nematodes in the familySteinernematidae Travassos, 1927 have great potentialfor use as biological control agents for soil, inhabitinginsect pest (Gaugler and Kaya, 1990; Kaya and Gaugler,1993). Recent surveys related to this family have reportedthe presence of new isolates/species from Sri Lanka,(Amara Singhe et al., 1994), Puerto Rico (Roman andFigueroa, 1994), Portugal (Rosa et al., 1994) Canada(Mracek and Webster, 1993), Argentina (Stock, 1995),Korea (Choo et al., 1995; Stock et al., 1997) and China(Jian et al., 1997). Besides this, a number of EPN surveysin tropical and subtropical regions have also beenconducted by several workers. But specific survey formembers of Steinernematidae in India in general andMeerut in particular is still awaited. Thus, with the viewto make of general survey of this group in Meerut region,present investigation was started with the hope of itssubsequent use as biological control agent of soilinhabiting insect of economic importance.MATERIALS AND METHODSCommonly available insect, mole cricket Gryllotalpaafricana for the present investigations were collectedfrom soil from different localities of Meerut and identifiedwith the help of classical work of Imms (1960) and Davies(1977). Insects were anesthetized with the help ofChloroform. Subsequently, a thorough examination oftheir whole body cavity was made under stereoscopicbinocular microscope. Nematode parasites were pickedup with the help of a fine glass dropper. After removalfrom host, parasites were washed in normal saline andfixed either in A.F.A. fixative or in hot 70% Alcohol. Forthe study of morphology, parasites were cleared inGlycerin or Lacto phenol. Diagrams were made with thehelp of Camera Lucida to support the morphologicalobservations.RESULTSWorms collected by author exhibit close resemblance withSteinernema scapterisci Nguyen and Smart, 1990.However, it exhibits minor variations in somemorphological features besides differences andmeasurements in various body parts. It is therefore brieflyredescribed as such (Tables 1 and 2). Body  elongatedand cylindrical. Females are 2 to 3 times longer than males.Males provided with curved spike like tail. In both maleand female specimens immediately behind theoesophageal bulb with exact two vesicle like structure,place one above the other. Sometimes, it is seen that inthe lumen of these vesicle, there exists someintravesicular structures are untethered clusters orenucleate spherical bodies embedded in amorphousmatrix of vesicular lumen. The morphological details ofmale and female specimens are given as follows:Male (Plate I and Plate III):  Body of male worm measures1.3-1.7 mm in length. Maximum width was recorded inequatorial region of the body, 0.11-0.13 mm. Body coveringsmooth, striations not visible. A pair of amphids is presentout side the buccal capsule. Oesophagus muscular, welldeveloped and measures 0.16 – 0.17 mm in length. Unlikeother nematodes, oesophagus is not differentiated intocorpus and isthmus. But the posterior part is slightlyswollen giving appearance of oesophageal bulb. Intestineis simple and occupy the whole width of parasite andfinally converging into anus. Testis single reflexedoccupying 2/3rd of the length of parasite from theposterior end. At the anterior end,  testis becomes thinwalled tube and get coiled. Anus is sub-terminal inlocation at 0.040-0.046 mm from the posterior end. Tail ofmale was short and blunt measuring 0.04-0.06 mm in length.2008APPLIED    ANDNATURAL SCIENCEFOUNDATIONANSF220H. S. Singh et al. / J. Appl. & Nat. Sci. 2 (2): 219-224 (2010)Spicule present and the bifurcated into two parts. Spiculetubular in outline and covered with sclerotized cuticle.Proximal spicule larger measuring 0.07-0.09 mm.Capitulum of proximal spicule broad and very well set offfrom the corpus or calomus, broad, flattened which tapersto form the last part called blade or lamina, with the helpof a narrow neck like constriction. Distal spiculecomparatively short, measuring 0.05-0.07 mm in length.Gubernaculum boat shaped, with anterior part thin, longand ventrally curved. Spicule glide along gubernaculumin two grooves separated by a needle- shaped cuneus.Eleven or 12 pairs  of single genital papillae observed.Female  (Plate II and Plate IV) : Body of worm  cylindricalmeasures 3.3-4.0 mm in length and  comparatively longerthan that the male. Width of worm is 0.21-0.25 mm.Striations not visible in any part of the body. Mouthterminal, body cavity inconspicuous. Nerve ring locatedat a distance of 0.15 mm from the anterior tip. Oesophagussimple, cylindrical with slightly expended posterior part,measuring 0.21-0.25 mm in length. However, posteriormost part somewhat bulbous forming the oesophagealbulb measuring 0.042 - 0.045 x 0.050 - 0.052 mm. Intestinesimple and long tube, which terminates into anus. Anuslocated at a distance of 0.06-0.08 mm from the posteriorend. Female nematodes possess two sets of reproductiveorgans, didelphic. Vulva equatorial in location. Vaginahighly muscular and extended in the form of two fingerlike projections called epiptygma. Uteri amphidelphic andopen into rounded spermatheca. Ovaries from the eitherside extend towards middle and cross each other at thelevel of vulva giving ‘X’ like appearance. Eggs smallrounded in outline, thin shelled measuring 0.04-0.05 mmin diameter. In the distal part of uterus eggs are fullysegmented. Tail is bluntly conoid measuring 0.020-0.023mm in length.Plate I. S. scapterisci Nguyen and Smart, 1990 male Figs. 1-5: 1) Anterior region. 2) Spicule 3)  Anterior region enlarged  4)Posterior region enlarged,  5) Male entire.221DISCUSSIONSteinernema scapterisci was first of all reported byNguyen and Smart (1990) from Scapteriscus vicinus atUruguay, South America. During course of study,nematode parasite of Gryllotalpa africana, investigatorscame across a few specimens of host infected withPlate II. S. scapterisci Nguyen and Smart, 1990 female Figs.1- 6. 1) Anterior region enlarged 2) Posterior region enlarged 3)Anterior region 4) Vulva 5)  Eggs, 6)  Female entire.nematode parasite of genus Steinernema Travassos,1927. On subsequent study, it was found that worms atdisposal of the authors resembles closely with S.scapterisci, Nguyen and Smart (1990). However, theoriginal description of S. scapterisci suffers from somemorphological lapses, minor variations in a few featuresH. S. Singh et al. / J. Appl. & Nat. Sci. 2 (2): 219-224 (2010)222Plate III. S. scapterisci Nguyen and Smart 1990 male Figs. 1-6. 1)  Photomicrographs of anterior region x 100, 2)  Photomicrographsof anterior region x 400, 3)  Photomicrographs of anterior region x 1000, 4) Photomicrographs of posterior region x 100, 5)Photomicrographs of posterior region x 400, 6) Photomicrographs of posterior x 1000.(1)(2)(3)(4)(5)(6)have also been noticed besides the differences inmeasurements of various body parts. It is, therefore,redescribed here in as such. The important variationswhich were noticed in the specimens at disposal of writersare:  Testis in the present specimens found extendedbeyond the equatorial region of the body,  in the originaldescription forwarded by Nguyen and Smart (1990), maleworm are equipped small spike like tail and vulva in femalespecimens less protruded. These variations in the presentspecimens could be due to presence of parasite inH. S. Singh et al. / J. Appl. & Nat. Sci. 2 (2): 219-224 (2010)223Plate IV. Steinernem scapterisci Nguyen and Smart 1990 female.Figs. 1-6. 1) Photomicrographs of anterior region x 100, 2)Photomicrographs of anterior region x 400, 3) Photomicrographs of anterior region x 1000, 4) Photomicrographs of posteriorregion x 400, 5) Vulva region x 1000, 6)  Eggs x 1000.(1)(2)(3)(4)(5)(6)different host or this could also be due to difference inzoogeographical niche of the parasite. Since these featuresare not of sufficient taxonomic merit. Thus can be treatedas variations only.Earlier, Nguyen and Smart (1990) have not mentionedany thing about the intestinal vesicle. But since thisstructure is very important as far as applications ofnematode as biological control agents is concerned.These vesicles are present immediately behind theoesophageal bulb in the form of two pockets. Each havingH. S. Singh et al. / J. Appl. & Nat. Sci. 2 (2): 219-224 (2010)224intravesicular structures. Presence of such structureshave also been reported by Bird and Akhurst (1983), Endoand Nickle (1995) and Martens and Goodrich Blair (2005).Martens and Goodrich (2005) were of opinion, that, theseintestinal vesicle contains subcellular structure withwhich microbes are found associated. These microbes infact appear to be the pathogenic to the host species inwhich this nematode is found parasitizing.ACKNOWLEDGEMENTSThe authors are thankful to the Head, Department ofZoology, C. C. S. University, Meerut, for providinglaboratory facilities and valuable suggestions. Authoritiesof  DST are gratefully acknowledged for financialassistance.REFERENCESAmara Singhe L.D., Hominick, W. M., Briscoe, B. R. and Reid, A.P. (1994). Occurrence and distributionof entomopathogenicnematodes in Sri Lanka. Journal of Helminthology, 68: 277-286.Bird A.F. and Akhurst R.J. (1983). The nature of the intestinalvesicle in nematodes of the family Steinernematidae. Int J.Parasitol., 13 : 599-606.Choo H.Y., Kaya H.K. and Stock S.P.(1995). Isolation ofentomopathogenic nematodes (Steinernematidae andHeterorhabditidae) from Korea. Japanese Journal ofNematology 25: 45-51.Davies, R. G. ( 1977). Imms General Textbook of Entomology.Champam and Hall, New York.Endo, B.Y. and Nickle, W. R. ( 1995). Ultrastructure of anteriorand mid regions of infective juveniles of Steinernema feltiae.Fundam. Appl. Nematol., 18: 271-294.Gaugler, R. and Kaya, H. K. (1990). Entomopathogenicnematodes in biological control. Boca Raton, Florida: CRCPress, 365 pp.Imms A.D. (1960).  A    General   Textbook    of  Entomology,Methuen London.Jian B., Reid,  A. P. and Hunt, D. J. (1997). Steinernemaceratophorum n.sp. (Nematoda: Steinernematidae) a  newEntomopathogenic   nematoda   from    north    east. China.Syst. Parasitol., 37: 115-12Kaya, H.K. and Gaugler, R. (1993). Entomopathogenicnematodes. Annual Review of Entomolgy, 38: 181-206.Martens, E. C. and Goodrich Blair, H. (2005). The Steinernemacarpocapsae intestinal vesicle contains a subcellular structurewith which Xenorhabdus nematophila associates duringcolonization intiation. Cellular Microbiology, 7: 1723-1735.Mracek, Z. and Webster, J.M. (1993). Survey ofheterorhabditidae and steinernematidae (Rhabditida,Nematoda) in Western Canada. Journal of Nematology, 25:710-717.Nguyen, K. B. and Smart G. C. Jr. (1990). Steinernemascapterisci n.sp. (Steinernematidae: Nematoda). Journal ofNematology, 22: 187-199.Roman, J. and Figueroa, W. (1994). Steinernema puertoricensisn.sp. (Rhabditida, Steinernematidae) a newentomopathogenic nematode from Puerto Rico. Journal ofAgriculture, University of Puerto Rico, 78: 167-175.Rosa, J. S., Martins, A., Mendes, C., Amaral, J. J., Lacey, L.A.and Simoes, N. (1994). Natural occurrence of soilentomopathogens in the Azores Islands. Abstracts VIthInternational celloquium on Invertebrate Pathology andMicrobial Control, 2: 275-276.Stock S.P. (1995). Isolation of entomopathogenic nematodesfrom the Pampean region of Argentina. Nematropica, 25:143-148.Stock, S. P., Choo, H.Y. and Kaya H. K. (1997). Anentomopathogenic nematode, Steinernema monticolum(Rhabditida: Steinernematidae) from Korea with a key toother species. Nematologica, 43: 15-29.Travassos L. (1927). Sobre O genera Oxystomatium. BoletinBiologica, 5: 20-21.H. S. Singh et al. / J. Appl. & Nat. Sci. 2 (2): 219-224 (2010)

Redescription of Steinernema scapterisci Nguyen and Smart, 1990: (Steinernematidae)

Present communication deals with redescription of the insect parasitic nematode, Steinernema scapterisci Nguyen and Smart, 1990, collected from the mole cricket, Gryllotalpa africana at Khurja, district (U.P.). The original description suffers from some morphological variations in the testis, tail and vulvular region.</jats:p

Redescription of Steinernema scapterisci Nguyen and Smart, 1990: (Steinernematidae)

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