Title

Back to index

To view images go to: Image List

ORDER RHABDITIDA
INFRAORDER TYLENCHOMORPHA
            Family Neotylenchidae
                        Genus Hexatylus

 

Genus Hexatylus Goodey, 1926
“Neotylenchinae.  Entomoparasitic generation: Adult female in insect haemocoel, elongate-obese.  Males and preadult infective female resembling those of most Sphaerularioidea, female with much larger stylet bearing basal knobs and having enlarged oesophageal glands, extremely elongate uterus filled with minute sperm and immature ovary.  Preadult female penetrates an insect host and matures in its haemocoel.  Free-living, mycetophagous generation:  Female: Body veriform, straight or slightly arcuate ventrally upon relaxation, about 1 mm long (0.76 - 0.9 mm long, maximum width 45 - 57 um in type species).  Cuticle finely striated.  Lateral fields each with six incisures, not areolated.  Cephalic region very low, continuous or slightly offset, smooth;  labial disc absent; oral opening circular, six inner labial and four cephalic papillae present; amphid apertures small, labial but slightly posterior to level of cephalic papillae; framework six-sectored at base, 12-sectored anteriorly. Stylet slender, about 8 -12 um long; conus shorter than shaft; basal knobs in type species duplex or bifid so that they appear as six swelllings; two to three guidings rings present around shaft.  Some stylet protractors pass through framework to attach to cuticle on top of head.  Oesophagus cylindroid or fusiform.  Nerve ring circum-intestinal.  Excretory pore behind nerve ring.  Oesophageal glands overlapping intestine, dorsal gland larger that subventrals. Vulva a long transverse slit, usually at less than two body-widths from anus.  Vagina directed anteriorly.  No postvulval uterine sac.  Prodelphic.  Uterus with a prominent crustaformeria.  Eggs elongate-oval; one or two eggs in uterus at any one time.  Oviparous.  Oviduct with two consecutive rings of four cells each or two rows of seven to nine cells (Geraert, 1976).  Ovary outstretched, tip may be reflexed.  Female tail elongate-conoid, pointed, may be filiform.  Rectum and anus distinct; rectum acts as a feeding pump.  Male: Stylet present.  Testis producing minute rounded sperm.  Spicules anteriorly expanded, arcuate, cephalated.  Gubernaculum simple, fixed.  Bursa distinct, terminal or subterminal.  Juveniles essentially similar to female.” Siddiqi 2000

References:

Powers T. and P. Mullin. Plant and Insect Parasitic Nematodes. University of Nebraska Nematology Website. http://nematode.unl.edu/

Siddiqi, MR.  2000.  Tylenchida.  Parasites of Plants and Insects, 2nd Edition. CABI Publishing. 848pp.