Heterorhabditis indica

Poinar, Karunakar & David 1992




Females: Head and structures in anterior end similar to those of the species H. bacteriophora.
Gonads amphidelphic reflexed with sperm occurring in the proximal portion of the ovotestis of hermaphroditic females. Amphimictic females with sperm in the proximal portion of the oviduct. Vulva of amphimictic females narrow, surrounded with copulation plug after mating. Anal region of amphimictic females and especially hermaphrodites conspicuously swollen. The anus occurs approximately at the anterior third of the anal swelling. Rectum heavily cuticularized and a conspicuous valve separates it from the intestine.

Hermaphroditic females (n=12): L=2700 micrometers (um) (2300-3100); greatest diameter=132 um (107-145); length of stoma = 6 um (5-8); width of stoma = 8 um (6-10); anterior end to nerve ring = 115 um (104-123); anterior end to excretory pore = 173 um (163-187); anterior end to base of esophagus = 172 um (163-179); tail length=92 um (72-110); body diameter at anus= 44 um (38-51); V %= 47 (45-50); anal swelling extended from body = 11 um (5-14).

Amphimictic females (n = 12) : L =1600 um (1200-1800); greatest diameter =95 um (76-113); length of stoma = 5 um (4-8) ; width of stoma = 7 um (5-8); anterior end to nerve ring = 92 um (88-96); anterior end to excretory pore = 127 um (118-138); anterior end to base of esophagus = 131 um (120-139); tail length = 76 um (66-88); body diameter at anus = 26 um (22-32); V%= 48 (40-53); anal swelling extended from body = 2 um (1-3)

Males : Anterior region similar to that of females, but smaller. Nerve ring near the basal bulb. Testis single, reflexed. Spicules paired and separate, with pointed tips; capitulum usually set off from shaft; blade with single medial rib. Gubernaculum flat, narrow, approximately half the spicule length, not reflexed at tip. Bursa open, peloderan, with a double membrane, one running external and the other internal to the bursal papillae; bursa with only seven normal papillae, the last two (8 and 9) are generally atrophied, highly modified (round or very slender) or absent. From anterior to posterior, bursal pair No. 1 are normally located anterior to the spicule heads, are straight and reach the bursal rim, pairs No. 2 and 3 form a group located near the middle of the spicules. They are straight and reach the bursal rim. The fourth, fifth and sixth pairs form another group located near the cloacal opening. The fourth pair turn outward (laterally) and do not reach the bursal rim, the fifth and sixth pair turn ventrally (inward) and usually reach the inner bursal rim. The seventh pair are often branched or swollen at their base, are variable in form (straight, bent outward or inward) and may or may not reach the bursal rim. The eighth and ninth pairs are often absent but if present are modified in being short, narrow or swollen. They may also be branched and sometimes are asymmetrical with No. 8 present and No. 9 absent on one side and both present on the opposite side (always reduced in length or width).


 Holotype (male) L = 668 um; greatest diameter=38 um; stoma length = 3 um; stoma width = 5 um; anterior end to nerve ring = 80 um; anterior end to excretory pore = 120 um; anterior end to base of esophagus = 99 um; reflexion of testis = 83 um; tail length = 29 um; anal body width = 23 um; spicule length = 36 um; greatest width of spicule = 5 um; gubemaculum length = 19 um; width of gubemaculum = 0.9 um.
Allotype (hermaphrodite) : L = 2300 um, greatest width. = 114 um; stoma length = 6 um; stoma width =8 um; anterior end to nerve ring = 122 um; anterior end to excretory pore = 162 um; anterior end to base of esophagus = 164 um; tail length = 88 um; anal body width = 42 um; anal swelling = 13 um.
Males (n = 12): L = 721 um (573-788); greatest diameter = 42 um (35-46); length of stoma = 3 um (2-4); width of stoma = 5 um (4-6); anterior end to nerve ring = 75 um (72-85); anterior end to excretory pore = 123 um (109-138); anterior end to base of esophagus = 101 um (93-109); reflexion of testis = 91 (35-144); tail length = 28 um (24-32); body diameter at cloacal opening = 23 um (19-24); spicule = 43 um (35-48); greatest width of spicules = 5 um (4-6); gubernaculurn = 21 um (18-23); greatest width of gubernaculum = 0.90 um (0.6-1.2); ratio length of gubemaculum/length of spicules = 0.5 (0.4-0.6).

Infective juveniles:
Infective juveniles (third stage juveniles inside second stage cuticles) body shorter than those of previously described species. Labial region with a large dorsal tooth . Stoma walls opened and not collapsed at base. Outer second stage cuticle strongly ribbed longitudinally and closely appressed to the third stage cuticle. Hemizonid quite distinct and located just anterior to excretory pore. The smaller less distinct hernizonion is located in the anterior intestinal region. Ventricular portion of intestine devoiding of intestinal cells and forming an intestinal pouch which is filled with symbiotic bacteria. These bacteria also occur in the lumen of the intestine, mainly the anterior portion.

Infective juvenile (ensheathed; n = 25): L = 528 um (479-573); greatest diameter= 20 um (19-22); anterior end to nerve ring = 82 um (72-85); anterior end to excretory pore = 98 um (88-107); anterior end base of esophagus = 117 um (109-123); tail length = 101 um (93-109); anterior end to hemizonid = 91 um (85-98); anterior end to hernizonion = 121 um (115-131); stoma length = 10 um (8-11); a) = 26 (25-27); b) = 4.5 (4.3-4.8); c) = 5.3 (4.5-5.6); ratio D (anterior end to excretory pore/anterior end to base of esophagus) = 0.8 (0.79-0-90); ratio E (anterior end to excretory pore/tail length = 0.94 (0.83-1.03); ratio F (body diameter/tail length) = 0.20 (0.18-0.22).

Scirpophaga excerptalis (Pyralidae: Lepidoptera) used as a trap insect in soil; Coimbatore, Tamil Nadu, India.

Holotype (male) and allotype (hermaphroditic female) deposited in the Nernatology Collection at the University of California, Davis, California. Paratypes (one male, one female) deposited in the Laboratoire des Vers, museum at national d' Histoire Naturelle, Paris.

Heterorhabditis indica can be separated from the other species by following characters: This species possesses the shortest known infective juveniles which separates it from all other described species although there is some overlap between small individuals of H. bacteriophora and large individuals of H. indica . However, the values of ratio E (distance from head to excretory pore divided by tail length) and ratio F (body width divided by tail length) separate H. indica from all other described Heterorhabditis species.


Poinar, G. O., G. K. Karunakar, and H. David. 1992. Heterorhabditis indicus n. sp.(Rhabditida: Nematoda) from India: separation of Heterorhabditis spp. by infective juveniles. Fundamental and Applied Nematology 15, 467-472.