SOME BACTERIVOROUS NEMATODES FROM UTTARAKHAND, INDIA

Nematodes are biologically diverse and versatile, occupying an enormous range of habitats with variable feeding habits. They constitute nearlyy 90% of all Metazoan in number and have 26646 recorded species with 8359 species parasitic in vertebrates, 10681 species free-living, 4105 species parasitic in plants and 3501 species parasitic in invertebrate hosts (Hugot et 01., 2001). Further, soil-inhabiting nematodes predominate over all other soil animals, both in numbers and species. On the basis of feeding habits these soil inhabiting nematodes are classified as plant feeders, bacterial feeders, fungal feeders, predators and omnivores (Yeates et 01., 1993). Earlier most of the researches were focused on plant feeders because of the economic loses to agriculture. Though free-living nematodes (bacterial and fungal feeders) accounts to a large number of species, they have remained ignored for a long time due to their apparent low economic value. However, recent researches proved that these groups are important components of food chains and possess several attributes that make them useful ecological indicators (Freckman, 1988; Bongers, 1990; Neher, 2001). The Bacterivorous (bacterial feeders) nematodes occur in several orders like Rhabditida, Alaimida, Monhysterida, Aerolaimida, Enoplida, etc. A few papers on bacterivorous nematodes from Uttarakhand are of Siddiqi & Husain (1967) who recorded two species from Nainital and Dehradum districts; Khera & Chaturvedi (1977) recorded several species from the Tea Plantations of Dehradun; Jairajpuri & Khan (1982) recorded 3 species from Nainital & Dehradun Districts. Recently, Rizvi recorded these nematodes from Corbett Tiger Reserve (CTR), district Nainital (Rizvi, 2008) and from the Western Doon Shivalik (WDS) region of district Dehradun (Rizvi, 2007). The present paper reports 5 new records of bacterivorous nematodes from Uttarakhand, belonging to 3 orders, namely, Rhabditida (2 species); Aerolaimida (2 speces) and Alaimida (1 species). Out of these 5 species, 4 are being recorded from district Dehradun and 1 species from district Chamoli.


INTRODUCTION
Nematodes are biologically diverse and versatile, occupying an enormous range of habitats with variable feeding habits.They constitute nearlyy 90% of all Metazoan in number and have 26646 recorded species with 8359 species parasitic in vertebrates, 10681 species free-living, 4105 species parasitic in plants and 3501 species parasitic in invertebrate hosts (Hugot et 01., 2001).Further, soil-inhabiting nematodes predominate over all other soil animals, both in numbers and species.On the basis of feeding habits these soil inhabiting nematodes are classified as plant feeders, bacterial feeders, fungal feeders, predators and omnivores (Yeates et 01., 1993).Earlier most of the researches were focused on plant feeders because of the economic loses to agriculture.Though free-living nematodes (bacterial and fungal feeders) accounts to a large number of species, they have remained ignored for a long time due to their apparent low economic value.However, recent researches proved that these groups are important components of food chains and possess several attributes that make them useful ecological indicators (Freckman, 1988;Bongers, 1990;Neher, 2001).The Bacterivorous (bacterial feeders) nematodes occur in several orders like Rhabditida, Alaimida, Monhysterida, Aerolaimida, Enoplida, etc.

MATERIALS AND METHODS
Soil samples collected from soil around roots of Sugarcane, Mango, Litchi, Deodar, Sal and Pine from Dehradun, were processed by sieving and decantation technique.The nematodes were fixed, dehydrated and mounted in anhydrous glycerine.Measurements were made with an ocular micrometer on Leica WILD MPS 32.Photomicrographs taken with BX51DIC Olympus microscope and DP20 digital camera.Description : Body tapering slightly at extremities.Lips with the usual circles of six labial papillae and four cephalic papillae.Stoma 15 /lm long, 4 /lm wide; denticles on metarhabdions not clearly visible.Pharyngeal collar surrounds about half the stoma.Pharyngeal corpus with prominent basal swelling.Pharyngeal corpus without a median bulb.Basal bulb with valve plate.Lateral fields marked by four incisures.Nerve ring located at the middle of isthmus.Excretory pore opposite to anterior end of bulb.Vulva median, ovaries paired, opposed, reflexed.Female tail conical and long, 88-110 /lm.Phasmids located at one-fourth-one-third of the tail.

Remarks:
The measurements are in agreement with the earlier workers.This species is being recorded for the first time from district Dehradun, Uttarakhand.
Elsewhere: Germany, France, Bulgaria, Italy, England, Denmark, Soviet Union, China, Algeria and United States.Remarks: All measurements are in agreement with earlier workers except for slightly posteriorly situated vulva (41-50% of body length).This species is being recorded for the first time from Uttarakhand and also for the first time from rice fields.
Elsewhere: South Africa, Hungary and USA.
Description : Female : Body arcuate towards posterior extremity.Cuticle thick, strongly annulatked.Lateral Fields with three incisures.Lip region strongly set off, with conical lips, separated from each other by a distinct gap, with inner setose projections pointing towards oral aperture.Cephalic setae 2-3 /lm long, originating from second to third annule.Cervical setae 7-9 in number.Stoma with cuticularized cheilostome.Amphidial apertures plectoid, located anterior to middle of stoma, at 5-6 annules from base of lips.Pharynx with corpus, slightly narrower isthmus and a basal bulb with post bulbar extension leading to a small cardia.Basal pharyngeal bulb with a six pairs of denticulate ridges in grinder.Reproductive system didelphic, amphidelphic, genital tract weakly developed.Ovaries small, reflexed.Vagina straight with weak sphincter muscles.Vulval lips protruding.Tail 55-75 /lm long, ventrally curved, gradually narrowing towards tip with a subterminal mid dorsal spur and three pairs of caudal setae.
Male : Not found.
Remarks : Chiloplectus indicus is being recorded for the first time from Uttarakhand (district Chamoli) at an altitude of 10,000 ft.Soil around roots of thumer is a new habitat record.All the measurements are in agreement with Tahseen et al., (2004) except for smaller body length and slightly smaller tail length (L = 0.695-1.041mm; Tail = 0.068-0.105mm).
Habitat and Locality : Soil around roots of thumer, Taxus baccata and silver oak from Ghangharia, district Chamoli.

:
Soil around roots of Pine, Pinus sp from FRI forest, Dehradun.