Two species of Megastigmus Dalmanassociated with wild rose, Rosa webbiana (Rosaceae )from Ladakh, India with a key to the oriental species
(Hymenoptera: Chalcidoidea: Torymidae)
P.M. Sureshan
Zoological Survey of India, Gangetic Plains
Regional Station, Rajendra Nagar, Patna, Bihar
800016, India
Email: samanyu2003@yahoo.com
Date of online publication 26 May 2009
ISSN
0974-7907 (online) | 0974-7893 (print)
Editor: T.C. Narendran
Manuscript
details:
Ms
# o2104
Received
08 December 2008
Final
received 03 May 2009
Finally
accepted 08 May 2009
Citation:Sureshan, P.M. (2009).
Two species of Megastigmus Dalman associated with wild rose, Rosa webbiana(Rosaceae) from Ladakh, India with a key to the
oriental species (Hymenoptera: Chalcidoidea: Torymidae). Journal of Threatened Taxa1(5): 305-308.
Copyright: © P.M. Sureshan 2009. Creative Commons Attribution 3.0 Unported License. JoTT allows
unrestricted use of this article in any medium for non-profit purposes,
reproduction and distribution by providing adequate credit to the authors and
the source of publication.
Acknowledgements:I
am grateful to Dr. Ramakrishna, Director, Zoological Survey of India, Kolkatta, C. Radhakrishnan, Additional
Director, Zoological Survey of India, Calicut, Kerala and Dr. H.S. Mehta,
Additional Director, Zoological Survey of India, Solanfor giving an opportunity to participate in the Ladak expediton and providing necessary facilities and
encouragement. I am also thankful to Dr.Jhon. S. Noyes, Natural History Museum, London, U.K.
and Dr.S.Manickavasagam, Professor, Annamalai University, Tamil Nadu for kindly sending me
literature on Megastigmus. Thanks are also due to the Wild life Warden,
Jammu and Kashmir Wild life department, Leh and the
District Administration, Leh for issuing necessary
permits to visit various localities in Ladakh.
For Figures & Images – Click
here
Abbreviations: F1-Funicular segment 1;
MV- Marginal vein; OOL- Ocellocular distance; PMV- Postmarginal vein; POL- Postocellardistance; SMV- Submarginal vein; STV- Stigmal vein ;
T1-T3-Gastral tergites 1 to 3.
The
genus Megastigmus Dalmanbelongs to the subfamily Megastigminae of the family Torymidae. It is
represented by 132 species worldwide. Seven species of Megastigmus are
reported from the Oriental region, of which five are known from India. Megastigmus species are generally phytophagous, feeding on the seeds of Gymnosperms and
Angiosperms; some develop inside figs and are believed to be gall formers (on Eucalyptusand Acacia). Twelve species are
reported to be associated with Rosaceae, four
reported from Rosa species either as phytophagousor parasitic on associated hosts. They
also develop as parasites in galls of cynipoidea and
other insects. (Narendran 1994; Grissell 1995; Narendran et al.
2003; Noyes 2003). Among the
Indian species M. dorsalis (Fabricius) and M. karnatakensis Narendran are parasitic. Boucek (1988)
mentioned that in Europe parasitic species differ from phytophagousin having metallic gloss on the body. During the faunal exploration surveys conducted by the Zoological Survey
of India in the cold desert of Ladakh several
specimens of Megastigmus belonging to two
species were collected by sweeping over the wild Rose plant Rosa webbiana, which is common in the valleys of Ladakh range. In
detailed studies one group of specimens proved to belong to an undescribed species and the other group of specimens could
not be identified due to the non-availability of female specimens. A new
species of Megastigmus is described
here. A key to the Oriental species of Megastigmus is also provided, modified from Narendran et al. (2003).
The
type specimens are kept in the collections of Zoological Survey of the India, Gangetic Plains Regional Station, Patna, Bihar (ZSIP) and
eventually will be deposited in the National Zoological collections of
Zoological Survey of India, Kolkata (ZSIC) .
Megastigmus kashmiricus sp. nov.
(Figures
1-5; Image 1)
Material
examined:
Holotype: Female (on
card), 15.vii.2008, 34006’18.8’’N & 77012’58.3’’E, Alt. 3214m, Sumdado, (before chilling), Ladakh, Jammu & Kashmir,
India, coll. P.M. Sureshan, A.1201 (ZSIP)
Paratypes: 18 females, 1
male, (in alcohol) (Reg.No. A.1202), 1 Female, 1 Male
(on card) (Reg.No.A.1203) other data same as holotype;
2 females (on card), Leh, HemisNational Park, 4km before Hemis gompa,
5.vii.2008, 33054’51.8’’N
& 77042’46.4”E, Alt. 3568m, (Reg.No. A.1204); 2 males (in alcohol), Leh, Ganglas, 11.vii.2008, 34011’37.6”N
& 77036’04.9”E,
Alt. 3609m, (Reg.No. A.1205); 1 male (in
alcohol), Chanthang valley, Skidmang,
13.vii.2008, 33022’47.7”N
& 78016’14.3"E,
Alt. 4041m, (A.1206) coll. P.M. Sureshan(ZSIP).
Etymology
The
species name is derived from the name of the Indian state where the specimens
were collected.
Description:
Female: Length
2.1-3.64mm, ovipositor 1.6-2.1mm (Holotype 2.84mm,
Ovipositor 1.8mm).
Colour: Body testaceous, brownish black patches on ventral side of
thorax, tegula concolorouswith thorax; gaster with brownish cross bands
dorsally, sides mainly yellowish, ovipositor sheath brownish black, brownish
spot below antenna on lower face. Antenna brown with scape and pedicel
yellowish beneath. Eye brownish red. Ocelli pink. Wing hyaline with veins and pubescence brown, stigma blackish
brown, uncus transparent, very narrow brown infumation around stigma. Legs concolorouswith body except hind femora, tibiae and tarsi brown.
Head: (Fig. 3) In
dorsal view head width 1.6 x length , about 1.23x as long as pronotal collar, moderately long, brown and sparse bristles on vertex, occiput, and upper face up to level of antenna, lower face
clothed with pale hairs of medium length; temple somewhat straight, slightly longer than half length of eye;
vertex with oblique rugae on either side of median ocellus, rest of the area finely cross striate reticulate;
occipital carina weak, but distinct; POL
2.3x OOL. In front view head 1.2x as
broad as high; face below antenna with moderately distinct longitudinal rugae, other area finely striate reticulate; gena smooth and shiny; malar space half as long as eye; malargrooves distinct; eye weakly protruded,
length 1.3x width; scrobe deep and shiny,
reaching front ocellus;
clypeus with two distinct teeth. Antenna
(Fig. 1) inserted almost in centre of face, scapeexceeds level of vertex, pedicellus plus flagellum
3.4x as long as scape, pedicel slightly longer than
F1, anellus elongated, terminal funicular segments a little shorter, others
are of equal length, with a single row of long sensillae,clava 2.3x as long as preceding segment.
Thorax: with rather weak cross striations except on pronotal collar and mid lobe of mesoscutuma little coarser, with brown bristles. Pronotal collar as broad as long anda little shorter than mid lobe of mesosutum. Mesosocutum 1.5x as broad as long, notauli complete. Scutellum slightly
shorter than mesosocutum medially, 1.2x as long as
broad, weakly striate reticulate on anterior three-fifths; frenumnearly smooth , reticulation much obliterated, frenal furrow vaguely indicated. Dorsellum smooth. Propodeum (Fig.4)
medially 0.61x as long as scutellum, median area
irregularly and finely reticulate, sides almost shiny, otherwise with some
irregular rugae which tend to be longitudinal near
anterior margin, median carina faintly indicated, callus with dense white
hairs, base of each hair with reddish brown spot, spiracles oval, separated by 1.5x
their own diameter from hind margin of metanotum post spiracular sulcus distinct. Prepectus broad, triangular, finely reticulate. Mesopleuron finely
striate reticulate. Metapleurondistinctly reticulate. Forewing 2.31x as
long as broad; basal vein distinct, running obliquely to SMV, almost half as
long as MV; MV half as long as costal cell; basal cell partly closed; cubital hair line incomplete; disc with 4-7 scatted hairs towards tip;
costal cell hairy in distal three-fourth area, speculum very narrow, almost
absent, closed below; stigma conspicuous with uncusdistinct, stigma 1.5x as long as broad ( minus uncus). Relative lengths SMV 49, MV
21, PMV 21, STV 11. Hind coxa dorsally hairy. Relative
lengths: hind coxa, femur, tibia and tarsus 17, 32 ,34 ,26.
Gaster: Sessile,
smooth, 1.7x as long as hind tibia, 0.9x
as long as thorax and 0.65x as long as ovipositor sheath laterally; ovipositor
sheath 1.5x as long as gaster, and 2.3x as long as
hind tibia; posterior margin of T1-T3 incised in the middle.
Male: Length 2.3 -
2.7mm. Resembles female but differs in
having propodeum with median area with a few
longitudinal ridges, one very distinct in the form of a median carina,
remaining area finely reticulate; gaster with basal tergite produced in the form of a stalk, rest of gaster very short; ocelli larger
and more pigmented; antennae with funicular segments shorter.
Biology: Unknown. Associated with wild rose, Rosa webbiana (Rosaceae), probably phytophagous,
larvae feeding on the seeds.
Remarks: This species
closely resembles M. rosae Boucekin general morphology and structure but differs from it in having different
body colour pattern which is mainly yellowish,
antennae with pedicel only slightly longer than F1 and 3.2x as long as broad,
forewing rather sparsely hairy with stigma less round (1.5x as long as broad),
basal cell partly closed , cubitalhairline incomplete, disc with 4-7 hairs. (In rosae body with more brownish black
markings on head and thorax, antennae with pedicel 1.8-1.9x as long as broad,
distinctly longer than F1, forewing rather densely hairy , basal cell closed by
complete cubital and basal hairlines, disc with 7-10
isolated hairs, stigma more rounded, (1.1-1.2x as long as broad ). In the key to the West European Megastigmus by Boucek(1970) the species will run into couplet 6 and Megastigmus pictus (Forster) but it differs from the new
species in having forewing extensively hairy including disc of basal cell, stigmal knob much elongate and narrow, mid lobe of mesoscutumbrownish black in both sexes. M. picuts breed
in seeds of coniferous plants. M.aculeatus (Swederus) andM.nigrovariegatus Ashmead,
both species breed in seeds of various Rosa sp. also have large stigmal knob, body colouration as in the new species but M.aculeatusdiffers from the new species in having longer ovipositor which is about as long as or even longer than the body, rather stronger
cross-striae on shiny pronotumand mesoscutum. In the shape of forewing stigma, general body coloration and other
morphological characters the new species resembles the Japanese species M. chamaecyparidis Kamijo, M.pourthiaeae Kamijo, M.firmae Kamijo, M. thuyopsis Yano and M. tsugaphilus Kamijo but differs from all the above species as
follows. In M.chamaecyparidis thorax is weakly
convex in lateral aspect, scutellum with only 3 pairs
of bristles and pedicel almost as long as F1 and speculum of forewing large (in
the new species thorax highly convex, scutellum with
more bristles (seven pairs), pedicel little longer than F1 and speculum
reduced). M.pourthiaeae differs from the new
species in having ovipositor sheath about half as long as gaster,occiput slightly emarginated , mesoscutumwith dense long hairs , scutellum more hairy and
pedicel shorter than F1 (in the new species ovipositor sheath 1.5x as long as gaster, occiput strongly
emarginated, pedicel slightly longer than F1, mesoscutumwith scattered hairs and scutellum less hairy). M. firmaehas a long ovipositor which is much longer than the body and MV of forewing
distinctly shorter than PMV, whereas in the new species the ovipositor is only 0.7x as long as the body and the MV as long as PMV. M. thuyopsis differs from the new species in having three
pairs of bristles posteriorly on the mesoscutum, and scutellum, propodeum with a transverse carina and spiracles
separated by two times their own length from posterior margin of metanotum, ovipositor sheath distinctly shorter than gaster and half of thorax combined (in the new species mesoscutum and scutellum with
more than three pairs of bristles, propodeum with no
transverse carina and spiracles separated by 1.5x their own length from
posterior margin of metanoutm, ovipositor sheath
almost as long as gaster and half of thorax combined.M.tsugaphilus differs from the new species in
having an arched transverse depression medially on the propodeum,
forewing with more hairs on the basal half (basal cell) and scutellumwith only four or five bristles on each side (in the new species propodeum without an arched depression medially, forewing
less hairy (basal cell) and scutellum with more
bristles (seven pairs). M. cryptomeriae Yano differs from the new species in
having antenna with F1 more than 2x as long as wide and longer than F2, occiput shallowly emarginated, thorax weakly convex, propodeum with an arched transverse carina, gaster about as long as thorax, ovipositor sheath as long as gaster and thorax combined (in the new species F1 almost
twice as long as wide and as long as F1, occiputstrongly emarginated, thorax strongly convex in lateral view, propodeum without transverse carina, gastershorter than thorax , ovipositor sheath only 0.7x as long as head plus thorax combined). The North American M. nigrovariegatusdiffers from the new species in having the forewing distinctly clouded near the
stigma. Among the Indian species it
resembles M. viggianii Narendran& Sureshan and M. albizziae Mukerji but differs from these species by
characters given in the key.
2.Megastigmus sp.
(Fig.
6)
Male: Length 2.9-3.2mm. Colour mainly
brownish black, including antenna, and thorax completely, gasteryellowish brown. 8
specimens out of 22 with dorsal part of thorax partly and gastermainly yellowish. General morphology and structure similar to M. kashmiricus sp. nov.except for the following. Head with coarse
longitudinal rugae on face completely, vertex with
transverse striae in the form of rugae. Thorax with transverse striae coarser in the form of rugaeon pronotal collar and mesoscutumcompletely. Scutellumwith reticulation coarse, frenal groove distirnct. Propodeum with
moderate uniform reticulation, longitudinal rugaeirregular, median carina broken due to some irregular transverse rugae. Forewing more densely hairy with basal cell
completely closed by cubital and basal hair line,
disc with 10-12 isolated hairs, costal cell almost completely hairy, stigma
more rounded about 1.1x as long as broad (without uncus).
Material
examined:22 Males (3 on card, 19 in alcohol), Ganglas, Leh, Jammu & Kashmir, India, 11.vii.2008, 34011’37.6”N & 77036’04.9"E,
Alt. 3609m, (Reg.No. A.1207) ( ZSIP)
Remarks: The specimens appear almost
similar to M. rosae in general morphology and
structure especially of the antenna and forewing, but differ from it in having
body almost completely brownish black (except in some specimens thorax partly
and gaster mainly yellowish), pronotumand mesoscutum with rather coarse striation in the
form of rugae, scutellumincluding frenum with coarser reticulation, frenal furrow more clear, propodeumwith some transverse rugae which cut median
carina. The identity of the species can
only be fixed after the examination of female specimens which are not collected
in the present study. This species also
breeds in the wild rose plant along with M.kashmiricus but onlycollected from one locality.
References
Boucek, A. (1970). On some British Megastigmus ( Hym.Torymidae)wth a revised key to the West European species. Entomologist’s Gazette 21: 265-275.
Boucek, Z. (1988). Australasian Chalcidoidea (Hymenoptera). A biosystematic revision of genera
of fourteen families, with a reclassification of species. CAB
International, Wallingford, Oxon, U.K., 832pp.
Grissell, E.E. (1995). Toryminae (Hymenoptera : Chalcidoidea : Torymidae) a
redefinition, generic classification and
annotated world catalog of species. Memoirs on Entomology, International 2:
474.
Narendran, T.C. (1994). Torymidae and Eurytomidae of
Indian subcontinent (Hymenoptera : Chalcidoidea)Zoological Monograph. University of Calicut, Kerala, 500pp.
Narendran,
T.C., B. Raji & O.K. Remadevi(2003).A review of the Oriental species of Megastigmus Dalman (Hymenoptera : Torymidae). Entomon 28(4):
299-307.
Noyes,
J.S. (2003).Universal Chalcidoidea database.
http://w.w.w.nhm.ac.uk/jdsml/research-curation/projects/chalcidoids. (Last
updated May 2008).