A new species of Streblocera (Asiastreblocera) (Braconidae: Euphorinae) from Thailand with depressed ovipositor

7 Pages·2001·3.8 MB·English

by  Donald L J Quicke

HYM. RES.
J.
Vol. 10(2), 2001, pp. 138-144
<w Species of Streblocera (Asiastreblocera) (Braconidae:
Euphorinae) from Thailand with Depressed Ovipositor
Donald L. Quicke and Andy Purvis
J.
(DLJQ) Unit of Parasitoid Systematics, Department of Biology, Imperial College at Silwood
Park, Ascot, Berkshire SL5 7PY, UK, and Department of Entomology, The Natural History
Museum, London SW7 5BD, UK; (AP) Department of Biology, hnperial College at Silwood
Park, Ascot, Berkshire SL5 7PY, UK
—
Abstract. A new species of euphorine braconici, Streblocera (Asiastreblocera) olivera Quicke
and Purvis, new species, from Thailand is described and illustrated. This is the first record ofthe
genus from SE Asia. The description uses SEM to illustrate several features, including the ovi-
positor and facial horn for the first time. S. [A.) olivera is distinguished from the other four de-
scribed members of the subgenus.
Euphorine braconids are interesting be- segment which is not serratebutproduced
cause they attack adults of holometabo- into a large ventral, flattened lobe, and in
lous insects and adults and nymphs of having a very short ovipositor that is not
hemimetabolous ones. Probably related to exserted. Recently we were able to study
this, the adults show a remarkable range a series of a new species of Streblocera
of forms which are often believed to be (Asiastreblocera) from Thailand collected
associated with host manipulation, includ- by Dr Doug Yanega (University of Cali-
ing remarkably derived antennae and ovi- fornia, Riverside), and this has given us
DNA
positors (Shaw 1988). the opportunity to obtain sequence
Streblocera Westwood is a diverse genus data for the subgenus, and to study the
of principally tropical species that is cur- niorphology of its modified antenna and
rently divided into a number of subgen- ovipositor in more detail using scanning
era, largely on the basis of the form of the electron microscopy. Its D2-D3 28S rDNA
antem"ia. The hosts of Streblocera species sequence has been deposited in the EMBL
appear to be chrysomelid beetle adults database (accession number AJ302831)
(Maeto and Nagai 1985, Shaw 1985), and will be incorporated into a forthcom-
though host records are unavailable for ing molecular phylogenetic study of the
most species. The subgenus S. (Asiastreblo- non-cyclostome braconids (Belshaw and
cera) Belokobylskij was described on the Quicke, in press) and a combined molec-
basis ofa single species from China (S. cor- ular and morphological phylogeny of the
uiita Chao 1964) (Belokobylskij 1987) and Euphorinae (Quicke, Shaw and van Ach-
We
since then three additional species have terberg in preparation). are describing
been described, and collectively the this species here so as to make its name
known subgeneric range has been found available for future publications.
to include from Taiwan and Korea (Wang TERMINOLOGY AND COLLECTIONS
1983, Chou 1990, Ku 1997, Belokobylskij
and Ku 1998). Asiastreblocera differs from Body morphology terminology follows
all other Streblocera in having a facial horn, Achterberg (1979, 1988); wing venation
the antenna geniculate at the P' flagellar terms used follow Sharkey and Wharton
Volume 10, Number 1, 2001 139
(1997). Collections are abbreviated as fol- 1.8x width of mesoscutum; largely
lows: The Natural History Museum, Lon- smoorh. Clypeus distinctly protruding
don (BMNH); University of California, from plane of face. Face densely setose
Riverside (UCR). (Figs. 2, 3). Face as wide as eye height; fa-
cial horn large, up-curved, apically blunt
Streblocera (Asiastreblocera) (transverse) in dorsal profile, without
Belokobylskij mid-longitudinal ridge (Figs. 1-3). Cheek
Type species: Streblocera cornuta Chao 1964. height 0.26X height of eye, l.OX basal
— width of mandible in frontal aspect. Dis-
Diagnosis. The only euphorine subge- tance between anterior tentorial pits:
nus that has either a facial horn or a single shortest distance from anterior tentorial
or paired ventral projection from the 5"' pit to eye = 2.45:1.0. Width of head 2.35X
metasomal sternite. See Chen and van width of face. Temple strongly narrowed
Achterberg (1997) for additional features behind eyes (Fig. 1). Transverse diameter
of the subgenus.— ofeye 4.0X length oftemple (dorsal view).
Distribution. China, Korea, Taiwan, Eye 1.8X taller than wide in lateral aspect.
Thailand and Vietnam. Frons rather flat, medially glabrous, with
slight pitting behind antennal sockets (Fig.
Streblocera (Asiastreblocera) olivera 1). Transverse diameter of posterior ocel-
Quicke and Purvis, new species lus: distance between posterior ocelli:
(Figs. 1-16) shortest distance between posterior ocel-
Holotype female.—THAILAND: 2km lus and eye = 1:2:3. Occipital carina ab-
south of Ban Pha Bong (a small town sent medio-dorsally. Mesosoma: 1.7X lon-
south of Mae Hong Son), riparian forest, ger (including neck-like pronotum) than
low elevation, l.vi.2000, coll. D. Yanega maximally high. Pronope well-developed
(BMNH). Paratypes. 2 females, both with (Fig. 4). Mesoscutum smooth and shiny,
same data as holotype (one coated in plat- virtually glabrous except along notauli
inum and used for scanning electron mi- which are weakly crenulate anteriorly.
croscopy BMNH, the other deposited in Notauli deep, largely smooth except for a
UCR). few weak crenulae anteriorly; meeting
—
Diagnosis. This species may be distin- medio-posteriorly in front of scutellar sul-
guished from all other Streblocera species cus in a weakly depressed area with a few
by the possession of a single, non-furcate, striae but no distinct midlongitudinal ca-
medio-posterior projection from the 5"' rina (Fig. 4). Scutellar sulcus long, with a
metasomal sternite. single median carina (Fig. 4). Scutellum
—
DescriptioiL Female. Body length 2.6 rather convex; medioposteriorly with a
mm and of forewing 2.8mm. Antenna ge- pair of pits (Fig. 10). Propodeum with me-
niculate, 18-segmented, the terminal fla- dian carina, on anterior 0.6 and with two
gellomere partially divided on one side; pairs ofstrong transverse carinae; postero-
scapus 1.56X longer than 1"* flagellar seg- medially with several short transverse cMa-
ment which is strongly produced ventral- rinae (Fig. 10). Fore wing: Vein 1-SR+
ly into lobe; pedicellus with notch ven- absent. Vein SRI reaching wing margin
trally containing discrete row of short, 0.52 of distance from apex of pterostigma
erect sensilla (Fig. 7). Scapus with 6-9 di- to the wing tip. Vein SRI 1.9X longer than
agonal ridges medially (Figs. 2, 6); 1^' fla- m-cu. Vein 2-CU1 4x longer than 1-CUl.
gellar segment with three diagonal ridges Vein r arising 0.63 distance from base of
on the medio-ventral surface of the pro- pterostigma. Pterostigma 3.0-3.1X longer
truding lobe (Fig. 5). Head: 1.8X wider than wide. Hind xving: Lengths of veins 1-
than medially long (excluding facialhorn); M:lr-m:M+CU = 3.0:4.0:1.0. Legs: Length
140 Journal of H\menoptera Research
Figs. 1-4. Strcbloccm {Asinstn'bloccm) olivera sp. n., female paratype, scanning electron micrographs. \, Head,
dorsal view. 2, Head, facial view showing also, medioventral aspect of scapus with ridges, and an attached
insect larva below mandibles. 3, Head, lateral aspect of facial horn. 4, Pronotum and mesoscutum, dorsal
aspect. Scale bar (see Fig. 3): 1, 4 = 270 (xm; 2 = 430 ixm; 3 = 500 |xm.
of fore femur: tibia: basitarsus = 2.0:2.35: gites almost indistinguishable. 1st tergite
1.0. Hind femur: tibia: basitarsus = 2.2:3.0: 1.65X longer than maximally wide; maxi-
1.0. Hind tibial spurs almost equal in mum width 3.1X minimum width; dis-
length, each 0.25X length of hind basitar- tance from spiracles to posterior margin of
sus. Mctasoimr. First tergite with fine lon- tergite 1.25X distance between spiracles;
gitudinal striation postero-laterally (Fig. dorsopes very deep, separated from each
11);. remaining tergites completely other by an internal septum, visible
smooth; suture between 2nd and 3rd ter- through cuticle. 2nd tergite with a single
Volume 10, Number 2, 2001 141
Figs. 5-8, Strcbloccm {Asiastrebloccra) olivcra sp. n., female paratype, scanning electron micrographs. 5, 1"'
flagellar segment showing 3 ridges on dorso-medial surface. 6, Scapus, pedicellus and base of tlagellum,
arrows indicating ridges. 7, Detail of pedicellus, ventro-lateral aspect showing transverse basal groove with
row of short sensilla. 8, Anterior mesosoma, lateral aspect. Scale bar (see Fig. 7): 5 = 150 jxm; 6 =^ 270 (xm; 7
= 30 |jLm; 8 = 380 ixm.
transverse row of seta subposteriorly (Fig. dorso-ventrally depressed, apically trans-
12). Tergites 4 and 5 with distinct medio- verse in dorsal profile (Figs. 15, 16). Area
posterior protuberance (Fig. 12). Sternum between hypopygium and terminal ter-
8 of metasoma with a single, mediopos- gites setose (Fig. 16). Colour. Body pale
terior, apically rounded projection. Ovi- brownish yellow, the propodeum medi-
positor very short, not extending beyond oposteriorly and the anterolateral parts of
the apex of the hypopygium; markedly the 1"' metasomal tergite, somewhat dark-
142 Journalof Hymenoptera Research
Figs. 9-12. Strcblocem (Asiastirhloccrn) oUvcra sp. n., female paratype, scanning electron micrographs. 9, Me-
sosoma, wings and 1^' metasomal tergite, dorsal aspect. 10,Scutellum, metanotum and propodeum detail. 11,
1^' metasomal tergite showing fine lateral striations. 12, Metasoma, showing small medio-posteriorprotuber-
ances of tergites 4 and 5. Scale bar (see Fig. 11): 9, 11 = 200 |xm; 10, 12 = 100 \i.m.
ev, the legs and face whitish. Antenna sects, and their hosts often have highly
brown. sclerotized exoskeletons. Thus euphorine
Mr?/d'.—Unk—nown. ovipositors mostly appear adapted to pen-
Etymology. Named after Oliver Purvis. etrating intersegniental membranes or
similar vulnerable places on the host, and
DISCUSSION
the typical adaptation is moderate to
Most euphorines have moderately to strong lateral compression (see Achter-
highly modified ovipositors that are as- berg and Quicke 2000). A few euphorines
sociated with oviposition into adult in- have solved the problem differently, for
Volume 10, Number 1, 2001 143
Figs. 13-16. Strcbloccrn {Asinstrcbloccra) olivcra sp. n., female paratype, scanning electron micrographs. 13,
Apex of metasoma, lateral aspect, showing ovipositor (Ov) and protuberance (P) from5"^ metasomal sternite.
14, Detail of ovipositor from dorsolateral aspect. 15, Postero-ventral view of apex of metasoma showing
showing ovipositor (Ov), protuberance (P), and 'secretion' covered seta between ovipositor and ovipositor
sheaths. 16, Detail of apex ofovipositor showing its dorso-vental compression. Scale bar (see Fig. 15): 13, 16
= 250 |jLm; 14 = 300 |xm; 15 = 136 [x.m.
example, species of Spmthicopsis van Ach- esting because it shows that it is possible
terberg have a dorso-ventrally depressed to evolve from lateral compression (as in
and apically spatulate ovipositor, though S. (A.) cornufa Chao {vide Chen and van
unfortunately, their hosts are unknown Achterberg 1997: Fig. 49)—perhaps
(Chen and van Achterberg 1997). The dor- through an almost cylindrical intermedi-
so-ventral compression in some Asiastir- ate whose mode of function we can not
blocera, including the new species, is inter- guess at.
144 Journal of Hymenciptera Research
Although there has been speculation Achterberg, C. van and D. L. J. Quicke. 2000. The
that the modified antennae in Sircbloccra palaeotropical species of the tribeCosmophorini
Capek (Hymenoptera: Braconidae: Euphorinae)
may be involved in holding their beetle with descriptions of twenty-two new species.
hosts, there have been no actual observa- ZoologischcMcdedcliiigcn, Leiden 74: 283-338.
tions of this. The presence ofdiagonal stri- Belokobylskij, S. A. 1987. To the knowledge of the
ations on both the scapus and the ventral braconid wasps of the genus Strcblocera Westw.
surface of the 1"' flagellar segment is not (Hymenoptera, Braconidae) of the southern Far
unique to the new species described here East. EntoniologisclieskoeOhozrenie 66: 159-174.
Belokobylskij, S. A. and D. S. Ku. 1998. Notes on the
(Xuexin X. Chen, personal communica- Korean species of the genus Strehloeem with de-
tion) though there function is not known. scriptions of a new species and a key to Korean
They may be involved in host-restraint/ species. The Korean journal ofS\/fiteiuatic Zoology
manipulation, but it is also possible that 14:319-325.
they might act as stridules for sound pro- Belshchaawr,acRt.erantdranDs.itLi.onJ.sQwuhicekne.esItnimparteesss.oAfspsheyslsoign-g
duction. enyareuncertain: theevolutionofkoinobiosison
The setae in the anal area of all speci- concealed hosts by ichneumonoid parasitoids.
mens examined are covered with an ap- Systeiuatie Biology.
parently congealed substance (Figs. 15, Chao, H. 1964. Descriptions of four new species of
braconid wasps of the genus Strebloeera West-
16). If this material is a secretory product, wood (Hymenoptera). Aeta Zootaxononiica Siniea
it be involved in some marking function. 1: 153-162. (In Chinese with English summary.)
Unfortunately, such congealed materials Chen, X. andC. van Achterberg. 1997. Revisionofthe
are often ignored by taxonomists making subfamily Euphorinae (excluding the tribe Me-
it difficult to assess both their taxonomic teorini Cresson) (Hymenoptera: Braconidae)
distribution and how consistent they are from China. Zoologisehe Verhandelingen 313: 1-
217.
within a taxon. In addition, S. {A.) olivera Chou, L.-Y. 1990. The Braconidae (Hymenoptera) of
has the 4"' and 5"' metasomal sternitespar- Taiwan 11. The genus Strebloeera (Euphorinae).
ticularly densely setose, but these setae are lournal ofTaiwan Museum 43: 89-148.
not covered in secretion and their function Ku, D. S. 1997. A taxonomic study of the genus Stre-
is unknown though they could be sensory. bloeera Westwood from Korea. Inseeta Koreana 14:
65-80.
ACKNOWLEDGEMENTS Maeto, K. and K. Nagai. 1985. Notesonbraconidpar-
asitoids of Medythia nigrobilineata (Motschulsky)
We are indebted to DougYanega (EntomologyRe- (Coleoptera, Chrysomelidae), with descriptionof
search Museum, University of California, Riverside) a new species of Centistes Haliday (Hymenop-
forcollectingthisinterestingspeciesand makingma- tera: Braconidae). Kontyii, Tokyo 53: 729-733.
terial available for study, to Xuexin X. Chen for in- Sharkey, M. J. and R. A. Wharton. 1997. Morphology
fomation about work on Asinstrcbloccrn in China and and terminology, pp 19-37 in R. A. Wharton, P.
Korea, to Nicola Simpson for making the SEMs and M. Marsh and M. J. Sharkey (Eds) Manual ofthe
to David Orme for montaging the plates. The speci- New World Genera of the Family Braconidae
mens were exported under licence (No. 0741/481) is- (Hymenoptera). Speeial Pubtieatioii ofthe Interna-
sued by the Bangkok CITESofficeofthe Royal Forest tio)\al SocietyofHi/iuenopterists, No. 1.
Department. Shaw,S. R. 1985. Aphylogeneticstudyofthesubfam-
ilies Meteorinae and Euphorinae (Hymenoptera:
LITERATURE CITED Braconidae). Entoniography3: 277-370.
Shaw,S. R. 1988. Euphorinephylogeny: theevolution
Achterberg, C. van. 1979. A revision ofthesubfamily of diversity in host-utilisation by parasitoid
Zelinae auct. (Hymenoptera, Braconidae). wasps (Hymenoptera: Braconidae). EeologiealEn-
Tidjschrift voor Eniomologie 122: 241-479. tomology 13: 323-335.
Achterberg, C. van. 1988. Revision of the subfamily Wang, J.-Y. 1983. A new species of Strebloeera West-
Blacinae Foerster (Hymenoptera, Braconidae). wood (Hymenoptera: Braconidae: Euphorinae).
Zoologischc Vcrliiiiuiclin^cii, Leiden 249: 1-324. Eiitomotaxonomia 5: 231-232.