Des adultes et des juvéniles d'#Ektaphelenchoides winteri$ n.sp. ont été récoltés, attachés par leur stylet au tégument de larves de #Xylodiplosis$ sp. venant de sortir de troncs d'arbres fraîchement coupés. Chez les mâles, les spicules sont saillants et la distance apex-rostre est plus longue que la distance rostre-extrémité postérieure; l'extrémité de la queue est pourvue d'un mucron tubulaire, bien détaché, long de 4-11 micromètres. Les mâles mesurent 540-764 micromètres et les femelles 993-1350 micromètres; le stylet, dépourvu de boutons basaux, est long de 19-26 micromètres. Le contenu intestinal des nématodes - et particulièrement celui du sac intestinal postérieur de la femelle - est de couleur rose ce qui correspond à celle de l'hémolymphe des larves de #Xylodiplosis$ sp. (Résumé d'auteur

Hooper, D.J.

Hooper, D. J.

Rothamsted Repository

Ektaphelenchoides winteri n. sp. (Nematoda:Ektaphelenchidae) from wood fly larvae Xylodiplosis sp. (Diptera:Cecidomyidae)

Horizon / Pleins textes

Fundam. appl. Nemal.ol., 1995, 18 (5),465-470
Ektaphelenchoides winteri n. Sp.
(Nematoda : Ektaphelenchidae) from wood fly larvae
Xylodiplosis sp. (Diptera : Cecidomyidae)
David J. HOOPER
Department ofEntomology and Nematology, fnstitute of Arable Crops Research, Rothamsted Experimental Sialion, Harpenden,
Herls., AL5 2JQ England.
Accepted for publication 27 September 1994.
Summary - Ektaphelenchoides winten' n. sp., adults and juveniles, were found arrached by their stylet to the integument of wood-fly
larvae (Xylodiplosis sp.) that had emerged from freshly cut timber. Males have prominent spicules in which the apex to rosrrum
distance is greater than from the rosrrum [0 the distal tip; the tail has an offset terminal, rubular shaped, mucro 4-11 fLm long. Males
are 540-764 fLm long and females 993-1350 fLm longj their stylet is without basal knobs, 19-26 fLm long. The nematode intestine
contents, particLÙarly in the posterior intestinal sac of the female, were pink in colour corresponding with the pink haemolymph of
the fly larvae.
Résumé - Ektaphelenchoides winteri n. sp. (Nernatoda : Ektaphelenchidae) provenant de larves de Xylodiplosis sp.
(Diptera: Cecidornyidae) - Des adLÙtes et des juvéniles d'Ektaphelenchoides winteTi n. sp. ont été récoltés, arrachés par leur stylet
au tégument de larves de Xylodiplosis sp. venant de sortir de rroncs d'arbres fraîchement coupés. Chez les mâles, les spicules sont
saillants et la distance apex-rosrre est plus longue que la distance rosrre-extrémité postérieure; l'extrémité de la queue est pourvue
d'un mucron rubLÙaire, bien détaché, long de 4-11 fLm. Les mâles mesurent 540-764 fLm et les femelles 993-1350 fLmj le stylet,
dépourvu de boutons basaux, est long de 19-26 fLm. Le contenu intestinal des nématodes - et particulièrement celui du sac intestinal
postérieur de la femelle - est de couleur rose ce qui correspond à celle de l'hoemolymphe des larves de Xylodiplosis sp.
Key-words: Nemaroda, Ektaphelenchoides, Xylodiplosis, Tarsonemid mite.
An ektaphelenchid nematode was noticed attached to
the larvae of a wood fly, Xylodiplosls sp. (Diptera : Ceci-
domyidae), emerging from the vessels oflogs freshly cut
from an oak tree (Quercus robur L.). The nematodes
protruded from the fly larvae giving them a " porcu-
pine" appearance (Fig. 1 E). Ektaphelenchid nema-
todes are widely associated with bark beetles (Hunt,
1993) but this is the first record of an ektaphelenchid
nemarade attached ra an insect larva; it is described here
as Ektaphelenchoides wimen' n. sp.
Materials and methods
Xylodiplosis larvae, with nemarades attached, were
sent ra Rothamsted in water or in moist paper tissue.
The nematodes remained attached to sorne larvae which
were put directly into hot lacraphenol. Other fly larvae
and nematodes associated with them were killed and
fixed in glass caviry blocks by adding hot (99 oC) 5 %
formalin, T AF or F.P. 4 : 1 fixative, each plus 2 % glyce-
roi; the fixative was aUowed to evaporate over several
weeks until the specimens were left in glycerol, in which
they were mounted. Sorne nematodes fixed in 5 % for-
malin were transferred ta hot lacraphenol in which they
were mounted. Observations with the scanning electron
microscope (SEM) were attempted on specimens fixed
ISSN 1164-5571195/05 S 4.00/ © Gauthler- Villars - ORSrOM
as above, post-fixed in OS04' dehydrated to 100 % etha-
nol and then critical point dried using COz, and also on
specimens processed to glycerol. Details of the above
fixatives/methods are given in Southey (1986). Speci-
mens freshly fixed and mounted in T AF were phora-
graphed using a Zeiss Universal Photomicroscope with
differential interference contrast illumination. Measure-
ments were made of specimens mounted in lacraphenol
or glycerol.
Ektaphelenchoides winteri >!> n. sp.
(Figs 1,2)
MEASUREMENTS
See Table 1.
DESCRlPTION
Male: Lip region continuous with, or slightly narrow-
er than, body contour with rounded sides and flattened
anreriorly 7-8 f.Lm wide by 3-4 f.Lm high. When viewed
with the SEM the lip region has 5-6 very fine transverse
annulations which are not visible with the light micro-
" Named after Mr T. G. Winter who found specimens arra-
ched ro Xylodiplosis larvae.
465
D. J. HOCf{>eT
Table 1. MorphomelrUs of Ektaphelenchoides winteri n. sp.
(measurements in ~m).
Holotype Paratype Paratype
male males females
n 1 20 20
Stylet 20 19.1 ±022 22.4 ±0.37
(19-22) (19-26)
Excretory pore distance 80 81±1.3 9H L2
from lip region 72-91 (85-102)
L 709 65H 12.8 1211 ±28.1
(541-764) (993-1460)
31 29 ±0.6 31 ±0.6
(23-33) (25-35)
b 9.0 8.8 ±0.14 12.8 ±0.5
(7.8-9.7) (9.0-16.6)
b' 4.4 39 ±0.06 8.3±0.31
(3.4-4.4) (5.9-11.0)
13.6 15.1±028
(12.8-17.8)
c 2.1 2.3 ±0.06
(1.9-2.7)
GlorT 56 59 H2 62 HO
(51-71) (54-70)
V 80 ±0.4
(78-85)
Post vulval " sac" in l'Uival 0.5 ±0.03
body width (0.4-08)
Vulva ta " tail " tip (Vn in 7.4±0.14
vulval body widths (6.5-8.3)
Intestine endIYT % 67± 1.3
(53-76)
Spicules ADT • 25 25±0.3
(23-27)
Spicules A-T • 23 22 ±0.3
(20-24)
Spicules A-R • 14 IHO.3
(11-15)
Spicules R-T' 9 9.5 ±0.13
(9-11)
Tail mucra Il 7.7 ±0.45
(4-11)
" ADT = apex ro distal tip along dorsallimb; A-T = srraight line apex
te distal tip; A-R =apex to rosmun; R-T =rostrum to distal tip; b' =
body length -;- distance from anterior end to posterior end of oesoph-
ageal glands.
scope. The lip region is divided longitudinally by de-
pressions into six sectars; the lateral sectars are slightly
narrower than the others with oval-shaped amphid aper-
tures; the sublateral sectors each have a prominent ce-
phalic papilla on their outer margins. A labial disc was
not present. The body is curled ventrally when killed by
heat, the tail end curled ventrally upon itself. The body
cuticle has fine transverse annulations slightly less than
1 fl.m wide which are interrupted by the rather narrow
lateral field which has three incisures. Stylet 19-22 fl.m
long without basal knobs, the anterior cone is slightly
466
shorter than the shaft and is somewhat expanded ante-
riorly and thickened posteriorly at its junction with the
shaft. Male and female specimens detached From fly
larvae had a characteristic ring around the base of the
protruding cone. Median oesophageal bulb prominent,
oval ta squarish with refractive thickenings just posterior
ta the centre. Weil developed oesophageal glands over-
lap the intestine dorsally and extend just over t\vice the
distance from the lip region ta the base of the median
bulb. Excretary pore usually within half a body width
behind the median bulb, however in sorne specimens
put directly into hot lactophenol it appeared just anterior
ta the median bulb. The multinucleare testis extends
forward to just over half the body length. Small, round-
ed sperm in the vas deferens 2-3 fl.m in diameter. Tail
dorsally convex, ventrally concave, about 2.5 cloacal
body widths long, bluntly conoid with a rounded to
bluntly conoid terminus bearing a prominent tubular
mucro usually about 8 fl.m long. A prominent pair of
subventral papillae present about half way along the tail
plus a precloacal subventral pair opposite the spicule
rostrum. Spicules weil developed with a prominent,
elongated and rounded apex just over half the length
from the apex to distal tip; rostrum conical, moderately
developed; the distal dorsal and ventral limbs converg-
ing distally ta form a bluntly conical terminus. Spicule
shape somewhat variable, sometirnes those of the same
pair differ.
Female: Body length about twice that of the males;
body slightly curved ventrally when killed by heat. Lip
region slightly more offset from body than in the male,
stylet and oesophagus similar to the male. Intestine with
dense contents coloured pink the same hue as the hae-
molymph of the insect host. The intestine appears ta
end in a blind sac at about t\vo thirds the distance from
the vulva to the posterior end; no rectum or anus seen in
most specimens. However, in three specimens, out of
many put directly inta hot lactophenol, there was a cuti-
cular indentation suggesting a vestigial anus occurring at
63-65 % of the distance from the vulva ta the terminus,
indicating a tail region 4.3 to 5 anal body widths long.
Vulva at 78-85 % of the body length, a transverse sht
somewhat subventral, vulvallips inconspicuous. Uterus
and oviduct not weil differentiated often containing
sperm throughout. Uterine eggs very large (95-
107 x 20-23 fl.m) i.e. about five times as long as wide
whereas deposited eggs were somewhat farter (91-
lia x 29-32 fl.m). Ovary multinucleate throughout
much of its length, extending past the oesophageal
glands and sometirnes reaching the median bulb but not
seen reflexed. The uterine tissue extends posterior tO the
vulva for about half a vulval-body width but there is no
distinct post-vulval sac. Posterior part of the body about
seven vulval-body widths long with a conical terminus
which may be sharply pointed or end in a narrow, finely
rounded, tip.
Fundam. appl. NernalOl.
Ektaphelenchoides winteri n. sp.
A
G
Fig. 1. Ektaphelenchoides winteri n. sp. A: Female head with prolruded slylel as der.achedfromfly laroa, allachmenl "ring" arrowed; B :
Female - oesophageal region; C: Female - anlerior end; D : Male - anlmor end, excrelOry pore arrowed; E : Xylodiplosis sp. fly laroa with
E. winteri allached; F: Female, vulva arrowed; G : Male; H: Male lail; 1: Male - reproduclive lracl eScale bars: A-D, H = 10 J.lrn; E =
1 mm; F-G = 100 J.lrn; 1 =20 J.lrn).
Vol. 18, n° 5 - 1995 467
D. J. Hooper
10 Itm B
20llm AF 1- P
Sltm C
E
100lt m 0
100 Itm E G H
G
F
J
Fig. 2. Ektaphelenchoides winteri n. sp. A : Male oesophageal region -lateral; B : Male head region; C : Female - en face; D : Female; E:
l'vfale; F. Vulval region - ventral view; G: FemaLe - posten'or end, vestigial anus aTTowed; H: FemaLe - posterWr end with ute17.ne egg; 1:
Male - posten'or end; J-L: Variation in male tail shape; M-P: Variation in spicule shape.
468 Fundam. appl. Nematol.
Ektaphelenchoides winteri n. sp.
Table 2. Characters differenlialing species ofEktaphelenchoides
fro»! E. winteri n. sp.
Acknowledgements
Mr T. G. Winter of the ForeSt!)' Commission, Forest Re-
search Station, Alice Holt Lodge, Surrey, England noticed the
Xylodipwsis larvae attacked by nematodes and kindly sent the
specimens to the author. The larvae were confirmed as Xyw-
diplosis sp. by Dr K. M. Harris, CAB International Institute of
Entomology (I.I.E.), London. The tarsonemid mites were
identified by Dr D. Macfarlane also of I.I.E. Dr D. J Hunt,
CAB International Institue of parasitology, St Albans, En-
gland, helped in the classification of the nematode. Mrs Janet
Rowe conducted SEM studies and made the prints for Fig. 1.
a polythene bag. These fly larvae had a characteristic
pink colouration and the nematode intestine, particular-
ly at its posterior end in females, had the same pink
colour as the insect haemolymph. Adults and juveniles
of E. winleri n. sp. were frrrn1y attached by the stylet
which penetrated the insects' integwnent. Sorne speci-
mens remained attached when infested fly larvae were
put directly into hot lactophenol. Nematodes subse-
quently detached from the insect had a characteristic
ring around the stylet just anterior to the oral aperture
suggesting sorne form of adhesive attachment. Also at-
tached to the fly larvae were tarsonemid mites, Umm-
guitarsonemus sp. Attempts were made at the type local-
ity in two successive years to obtain more wood fly
larvae and their pupae and adults but none were found.
Rühm (1956) suggested that Eklaphelenchus spp. de-
rived nourishment from insect associates but this is the
first record of actual feeding by any ektaphelenchid ne-
matode. Their attachment to the wood fly larvae is simi-
lar to ectoparasitism recorded for the aphelenchid gen-
era Acugullurus, NOCluidonema and Vampyronema (see
Hunt, 1993).
Juveniles: Specimens ranging in body length from
200-570 j..Lm were also found attached to the integument
of the fly larvae. They curled ventrally into a " C " shape
when killed by heat. The lip region, stylet and oesopha-
gus is similar to adults; the stylet of even the smallest
specimens measured 15-16 j..Lm long. The posrerior end
of the body tapered to a cone shape similar to the female.
Moulting specimens shed the anterior cone part of the
stylet with the moulted cuticle.
TYPE HABITAT AND LOCALITY
Attached to larvae of Xylodiplosis sp. (Diptera : Ceci-
domyidae) emerging from logs of oak, Quercus robur L.,
eut from trees at Crickley Hill, Gloucestershire, En-
gland. National Grid Reference No. sa 930163.
TYPE SPEcrM.ENS
Hololype (male) on slide no. 86 Kll/1 and para type
males and females on slides Nos. 86 Kll/2-36 in the
Nematology slide collection of the Entomology and Ne-
matology Departrnent, Rothamsted Experimental Sta-
tion. Paratype slides also deposited with the USDA Ne-
matode Collection, Beltsville, Maryland 20705, USA
and the Muséum National d'Histoire Naturelle, Paris,
France.
DIAGNOSrS AND RELATIONSHIPS
Ektaphelenchoides winteri n. sp. is characterised by the
male having spicules with a prominent, elongated,
rounded apex and its tail with a prominent tubular mu-
cro. The male and female both have three lateral in-
cisures. The long female (1.0 to 1.5 mm) has a vulva at
about 80 % of the body length without a distinct post-
vulval sac; the posrerior end of the body has a conical
terminus.
E. winteri n. sp. is placed in the genus Eklaphelen-
choides Baujard, 1984 because of its non expanded lip
region, stylet without basal knobs, female lacking a dis-
tinct anus and rectum, an intestine ending in a blind
diverticulum and male tail with an elongated mucro. It is
differentiated in Table 2 from the four known species of
Eklaphelenchoides described by Baujard (1984). The
spicules of E. winleri n. sp. with the elongated apex are
somewhat similar to Eklaphelenchus macrobulbosus
Rühm, 1956 but the latter does not have an elongared,
offset, tail mucro, the spicule tip is curved dorsally and
the female is much shorter, L under 800 j..Lm vs above
993 j..Lm in E. winleri n. sp. As noted by Loof and Hoop-
er (1993) sorne species of Seinura, in which the anus is
indistinct, are close to Eklaphelenchoides. However, E.
winten' n. sp. is readily distinguished from ail Seinura
spp. by the spicules having a longer apex to rostrum
distance than rostrum to distal tip distance and also by
the characteristic, offset, tubular mucro on the male tail.
REMARKS
The infested Xylodiplosis fly larvae emerged from
freshly cut oak logs that had been stored for a few days in
E. altenuala
(Massey, 1974)
Baujard, 1984
E. compsi
Baujard, 1984
E. musae
Bau;ard, 1984
E. pini
(Massey, 1966)
Baujard, 1984
Adults without lateral incisures. Female
tail more filiform; post-vulval sac more
distinct; vulva anterior : V =61-63 vs 78-
85. Male rail with a fùamentous terminus
and spicules with shorter apex.
Adults without lateral incisures. Female
tail ventrally curved and sharply pointed;
post-vulval sac 1.6-4.6 vulval body
widths long. Male tail with two pairs of
subventral papillae posteriorly; spicules
with shorter apex.
Female without lateral incisures, rail more
filiform, vulva anterior: V = 67 (64-69)
vs 80 (78-85). Males unknown.
FemaJe tail more f.ùiform, post-vulval sac
more distinct; vulva anterior: V = 70
(67-74) vs 80 (78-85). Male tail more
conical with spike-shaped mucro; spi-
cules with shorter apex.
Vol. 18, n° 5 - 1995 469
D. J. Hooper
References
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NémalOl., 7 : 147-171.
HUNT, D.]. (1993). Aphelenchida, Longidoridae and Trichodo-
ridae: lheir syslemalus and bionomus. CAB International,
Wallingford, England, 352 p.
470
LOOF, P. A. A. & HOOPER, D.]. (1993). Redescription of
Seinura demani (T. Goodey, 1928)]. B. Goodey, 1960 (Ne-
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Fundam. appl. NernalOl.


Ektaphelenchoides winteri n. sp. (Nematoda : Ektaphelenchidae) from wood fly larvae Xylodiplosis sp. (Diptera : Cecidomyidae)

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