J. HYM. RES.
Vol. 13(2), 2004, pp. 243–249
A New Species of Quadrastichus (Hymenoptera: Eulophidae):
A Gall-inducing Pest on Erythrina (Fabaceae)
(IKK, JLS) CSIRO Entomology, GPO Box 1700, Canberra, ACT 2601, Australia;
(GD) CIRAD TA 40L, Campus International de Baillarguet-Csiro, 34398 Montpellier Cedex 5,
France; email: email@example.com
Abstract.—Quadrastichus erythrinae Kim sp.n. is described from Singapore, Mauritius and Re´-
union. This species forms galls on the leaves, stems, petioles and young shoots of Erythrina var-
iegata and E. fusca in Singapore, on the leaves of E. indica in Mauritius, and on Erythrina sp. in
Re´union. It can cause extensive damage to the trees.
Key words.—Hymenoptera, Eulophidae, Quadrastichus, phytophagous, gall inducer, Singapore,
Mauritius, Erythrina, Fabaceae
Species of Eulophidae are mainly para-
sitoids, but secondary phytophagy in the
form of gall induction has arisen on many
occasions (Boucˇek 1988; La Salle 1994;
Headrick et al. 1995; Mendel et al. 2004;
La Salle 2004). Gall-inducing Eulophidae
generally belong to two groups: Opheli-
mini is an Australian lineage which con-
sists mainly of gall inducers on eucalypts,
but perhaps also on some other myrta-
ceous hosts (Boucˇek 1988; La Salle 2004);
and Tetrastichinae includes several in-
stances of gall induction, but it is ques-
tionable that these represent a single evo-
lutionary event (La Salle 2004). Genera of
Tetrastichinae where gall induction is
known to occur include Quadrastichodella,
Oncastichus, Epichrysocharis, Aprostocetus,
Paragaleopsomyia, Ceratoneura, ‘Exurus’,
and Leptocybe (La Salle 2004; Mendel et al.
Several species of tetrastichine gall in-
ducers have become invasive pests, partic-
ularly in the last decade, these include:
Quadrastichodella nova Girault (Flock 1957,
as Flockiella eucalypti; Timberlake 1957, as
Flockiella eucalypti; Boucˇek 1988); Oncasti-
chus goughi Headrick & LaSalle (Gough
1988; Redak and Bethke 1995; Headrick et
al. 1995); Epichrysocharis burwelli Schauff
(Schauff and Garrison 2000); and Leptocybe
invasa Fisher & La Salle (Mendel et al.
2004). Quadrastichus erythrinae Kim sp.n.
has recently achieved pest status in Sin-
gapore, Mauritius and Re´union. Erythrina
trees have been grown in these areas for
decades, and this species has never been
recorded from them. Although its exact
origin remains unknown, it is likely to
represent another example of an invasive
There are approximately 110 species of
Erythrina around the world, mostly found
in tropical regions (Mabberly 1987). Their
beautiful red ﬂowers have earned them
the common name of coral trees, and
made them a popular tree to be used in
landscaping in many tropical regions.
Recently, a eulophid species was found
from galls on Erythrina in Singapore and
sent to one of us [JL]; at about the same
time galls were found in Mauritius and
Re´union, with wasps being sent to another
of us [GD]. Comparison of the two sam-
ples showed that there was a single, wide-
spread species involved. This wasp can
cause severe damage to Erythrina trees,
and has become a nuisance in these coun-
Records of gall-inducing wasps on Ery-
thrina are not extensive. Annecke & Moran
(1982) reported on Erythrina galls in South
Africa. Five species of chalcidoid wasps
were reared from these galls, the most
common being a Eulophidae sp. and a
Eurytoma sp. (Eurytomidae). At that time,
the Eurytoma was suspected as being the
gall inducer. Recent examination of the
material (by Dr. G.L. Prinsloo) has shown
that there are two eulophid species pres-
ent, but neither of them are the same as
Q. erythrinae. Because this species was
found on Re´union and Mauritius, one of
us [GD] compared this species with all
species described by Risbec from Mada-
gascar; however, it did not agree with any
previously named species.
Quadrastichus erythrinae Kim represents
the ﬁrst record of a gall inducer in the ge-
nus Quadrastichus. Species of Quadrastichus
have a variety of biologies: many are par-
asitoids of gall-inducing hosts, such as Ce-
cidomyiidae (Diptera) and Cynipidae (Hy-
menoptera); others are parasitoids of Bu-
prestidae and Curculionidae (Coleoptera),
or Agromyzidae and Tephritidae (Dip-
tera); Q. sajoi (Szele´nyi) larvae are preda-
tors of eriophyid mites within galls (Gra-
ham 1991, La Salle 1994, Hansson and La
Terminology used in this paper is taken
from Gibson (1997) and Graham (1987);
OOL, ocell–ocular distance; POL, post-
ocellar distance; MPS, multiporous plate
Acronyms used in the text are as fol-
lows. ANIC, Australian National Insect
Collection, CSIRO Entomology, Canberra,
Australia; BMNH, The Natural History
Museum, London, UK; CIRAD, Centre de
Coope´ration Internationale en Recherche
Agronomique pour le De´veloppement;
CNC, Canadian National Insect Collec-
tion, Ottawa, Ontario, Canada; MZB, Mu-
seum Zoologicum Bogoriense, Bogor, In-
donesia; PPRI, Biosystematics Division,
Plant Protection Research Institute, Preto-
ria, South Africa; QMB, Queensland Mu-
seum, Brisbane, Australia; USNM, United
States National Museum of Natural His-
tory, Washington, D.C., USA.
Quadrastichus erythrinae Kim, sp.n.
02.vi.2003, He Liansheng, reared from
galls on Erythrina fusca (ANIC).
, Same data as Ho-
BMNH, CIRAD, CNC, MZB, PPRI, QMB,
Non-type material: MAURITIUS: Bras
d’Eau, 04.iv.2003, D. Ramkhelawon, vii.03,
ex. Erythrina indica leaves (12
ANIC); Quatre Bornes, 17.vii.2003, (S. Per-
malloo), ex. leaf galls on Erythrina indica
, ANIC). LA RE
Pierre, Bassin Plat, 06.xii.2000, G. Delvare
& A. Franck, ex. galls on Erythina sp. (33
CIRAD); Saint-Benoıˆt, 24.ii.2003, S.
Quilici, ex. galls on Erythina sp., Ref. N
RQ 4611 & Cirad 18009 (21
Female Length 1.45–1.6 mm. Dark
brown with yellow markings. Head yel-
low, except gena posteriorly brown. An-
tenna pale brown except scape posteriorly
pale. Pronotum dark brown. The mid lobe
of mesoscutum with a ‘‘V’’ shaped or in-
verted triangular dark brown area from
anterior margin, the remainder yellow.
Scapula yellow. Scutellum, axilla and dor-
sellum brown to light brown. Propodeum
dark brown. Gaster brown. Fore and hind
coxae brown. Mid coxa almost pale. Fem-
ora mostly brown to light brown. Speci-
mens from Mauritius are generally darker
than those from Singapore.
Head (Figs 1–2). Ocellar triangle sur-
rounded by groove; transverse groove ex-
2, 2004 245
Figs. 1–6. Quadrastichus erythrinae sp. n.—1. Head, frontal view; 2. Head, dorsal view; 3. Head and thorax,
lateral view; 4. Mesosoma, dorsal view; 5. Gaster, lateral view; 6.
Genitalia, dorsal view.
tending from lateral ocellus to eye. POL
1.6–2.0 times longer than OOL. Frons with
broad median area, but without median
carina. Toruli situated at level of lower eye
margin. Shallow groove present beneath
torulus, extending slightly over half the
distance from torulus to clypeal margin.
Gena slightly swollen and malar sulcus
only slightly curved, without triangular
fovea below eyes. Clypeal margin biden-
Antenna (Fig. 7) with one large anellus.
All funicular segments 1.3–1.6 times lon-
ger than wide and each segment approx-
imately equal in length and width to the
others. However, under the microscope
with slide-mounted antenna, each succes-
sive segment appears slightly wider than
previous one. Sensilla (MPS) slightly
shorter than length of funicular segment,
each sensilla reaching to the next funicular
segment; 1–2 sensillae visible on each seg-
ment in lateral view. Scape not extending
above the vertex.
Mesosoma (Figs 3–4). Median line on
the mid lobe of mesoscutum very weak to
absent but usually at least indicated in cer-
tain angles and light; if indicated, it can be
seen superﬁcially only in posterior half.
Mid lobe of mesoscutum with 3 to 5 short
adnotaular setae. Scutellum with distinct
submedian lines and sublateral lines; 2
pairs of setae on scutellum (occasionally
with an additional seta), anterior seta sit-
uated well behind midlength of scutellum.
Precoxal suture distinct and extending
about 0.7 length of mesopleuron. Propo-
deal spiracle relatively large, whole rim
exposed. Propodeum without distinct me-
dian carina or paraspiracular carina. Pro-
podeal callus with 2 setae.
Wing (Figs 9–10). Submarginal vein
with 1 seta, situated slightly basal to the
middle. Costal cell without setae. Post-
marginal vein almost rudimentary; less
than 0.3 length of stigmal vein. Costal cell:
marginal vein: stigmal vein: postmarginal
3.9–4.1: 2.8–3.1: 1.0: 0.1–0.3. Cubital
line of setae not extending all the way to
basal vein, leaving the speculum partially
open behind; the speculum small.
Gaster (Fig. 5). Slightly longer than the
head plus mesosoma. Hypopygium ex-
tending 0.8–0.9 the length of gaster and
reaching up to the posterior margin of G6.
Ovipositor sheath not protruding, short in
dorsal view. Cercus with 3 setae, the lon-
gest one slightly curved and about 1.3 as
long as the others, which are subequal in
Male. Length 1.0–1.15 mm. Pale colora-
tion white to pale yellow as opposed to
yellow in female. Head and antenna pale.
Pronotum dark brown (but in lateral view,
only upper half dark brown; lower half
yellow to white). Scutellum and dorsellum
pale brown. Axilla pale. Propodeum dark
brown. Gaster in anterior half pale; re-
mainder dark brown. Legs all pale.
Antenna (Fig. 8) with 4 funicular seg-
ments; without the whorl of setae; F1 dis-
tinctly shorter than the other segments
and slightly transverse; about 1.4 wider
than long. Ventral plaque extending 0.4–
0.5 length of scape and placed in apical
Gaster shorter than female. Genitalia
(Fig. 6) elongate, with digitus about 0.4
length of the long, exserted aedagus. [Dor-
sally exposed parts of the genitalia were
Etymology. The speciﬁc name erythrinae
comes from the genus name of the host
Biology. Reared from galls on Erythrina
variegata L., E. fusca Lour. (
Willd.) and E. indica L. (Figs 11–12). Inside
the leaf galls there is usually only one
wasp per cell, while in the swollen tissues
of shoots, twigs and petioles more than
ﬁve individuals were observed.
Distribution. Singapore, Mauritius, Re´-
union. It is not known if this wasp is na-
tive to one of these regions or not.
This species ﬁts the deﬁnition of Quad-
rastichus offered by Graham (1991): SMV
2, 2004 247
Figs. 7–10. Quadrastichus erythrinae sp. n.—7. Antenna,
; 8. Antenna,
; 9. Forewing; 10. Submarginal vein.
Figs. 11–12. Galls on stems, petioles, and young shoots of Erythrina induced by Quadrastichus erythrinae.
with 1 dorsal seta, antenna with all funic-
ular segments longer than wide and with
1–3 anelli in female and gaster longer than
the head plus mesosoma. However, the
species is distinct from all other Quadras-
tichus on the basis of the long hypopy-
The only key to species of Quadrastichus
of any region is Graham (1991) for Euro-
pean species. In this key, this species
would run to the anysis-group of Q. anysis
(Walker), Q. citrinus (Thomson) and Q.
xanthosoma (Graham) as follows: body
black and yellow as opposed to metallic
and without yellow markings; frons with
median area but without median carina;
gena slightly swollen, malar sulcus only
slightly curved, malar sulcus without a
large subtriangular fovea just beneath eye.
However, Quadrastichus erythrinae dif-
fers from the anysis-group because: clypeal
margin bidentate, scape not exeeding
above the vertex, apex of hypopygium ex-
tending distinctly beyond middle of gas-
ter. Males of the anysis-group have whorls
of long setae on the funicular segments
(Graham, 1991; Reina & La Salle, 2004),
however these are absent in Q. erythrinae.
Additionally, the anysis-group appears to
be restricted to leafminer hosts.
We are grateful to He Liansheng (Agri-Food & Vet-
erinary Authority of Singapore) for providing speci-
mens and information about the biology of Q. ery-
thrinae, and S.I. Seewooruthun (Ministry of Agricul-
ture, Mauritius) for sending us samples of Q. erythri-
nae. Gerhard Prinsloo, Plant Protection Research
Institute, Pretoria, offered advice and helpful com-
ments. A. Franck, from CIRAD Re´union made the
photographs of the infested Erythrina.
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