Xerothrips dissimilis new genus and species (Thysanoptera: Thripidae) from California and Nevada

7 Pages·1996·5 MB·

by  S Nakahara

PROC. ENTOMOL. SOC. WASH.
98(2), 1996, pp. 208-214
XEROTHRIPS DISSIMILIS NEW GENUS AND SPECIES (THYSANOPTERA:
THRIPIDAE) FROM CALIFORNIA AND NEVADA
SUEO NAKAHARA
Systematic Entomology Laboratory, PSI, Agricultural Research Service, U.S. Depart-
ment of Agriculture, 10300 Baltimore Avenue, Beltsville, MD 20705-2350, U.S.A.
Abstract.(cid:8212)A new genus Xerothrips and new species dissimilis are described from
California and Nevada. An unusual internal gland in abdominal segment III of the males
of dissimilis and a similar gland previously reported in other species are discussed.
Key Words: Thysanoptera, Thripidae, Xerothrips, dissimilis, internal gland
Xerothrips dissimilis new genus and spe- glandular area located on the anterior part
cies is known from the Mohave Desert of of the sternite. A similar glandular area
California and Nevada, and in the central was also observed in a male of B. limbatus
valley of California. This monotypic genus (Hood). Males of Pseudothrips beckhami
is closely related to Baileyothrips which oc- Beshear and Howell and P. inequalis
cur in the southwestern states. The females (Beach) have a reticulated glandular area
are macropterous and brachypterous and the similar to that of Baileyothrips and a small,
known males are brachypterous. Although slightly tuberculated area with an protrud-
collected from several plants grown com- ing orifice in front of the glandular area
mercially, X. dissimilis is not known to be (Beshear and Howell 1976), thus indicat-
a pest. ing that a internal gland is present. The in-
Males of many species in the family ternal gland was visible only in cleared and
Thripidae bear glandular structures of var- stained males. Because thrips are not nor-
ious shapes (circular, elliptical, transversely mally stained, the gland could be present
elongate and usually narrowed medially, v- in other species.
shaped, c-shaped) on abdominal sternites Acronyms of depositories of type speci-
IlI-VII and known in the literature as mens are as follows: CAS = California
(cid:8220)(cid:8216)glandular areas(cid:8217)(cid:8217) or (cid:8220)(cid:8220)(cid:8216)areae porosae.(cid:8221)(cid:8217) Academy of Sciences, San Francisco; CDFA
Males of Xerothrips dissimilis, new species, = California Department of Food and Ag-
lack glandular areas but have an unusual riculture, Sacramento; FSCA = Florida State
internal gland in abdominal segment III that Collection of Arthropods, Gainesville; INHS
opens through a small circular orifice near = Illinois Natural History Survey, Cham-
the anterior margin of the sternite (Fig. 9). paign; NHM = Natural History Museum,
A similar gland reported previously in an- London, United Kingdom; SMF = For
_ other species is associated with a glandular schungsinstitut Naturmuseum Senckenberg,
area also on abdominal sternite III. The Frankfurt am Main, Germany; UCD = Uni-
gland in males of Baileyothrips arizonen- versity of California, Davis; UCR = Uni-
sis (Morgan) illustrated by Kono and versity of California, Riverside; USNM =
O(cid:8217) Neill (1964) opens through an orifice on United States National Museum of Natural
the anterior part of an elliptical, reticulated History, Washington DC.
VOLUME 98, NUMBER 2 209
Xerothrips Nakahara, NEw GENUS males with a internal gland in abdominal
segment III. The two genera differ as fol-
Type species.(cid:8212)Xerothrips dissimilis,
lows. In Xerothrips, at least one pair of
new species.
pronotal posteroangular setae is present;
Female: Antenna 8-segmented, seg-
forewing of macroptera has two complete
ments III and IV with forked trichomes, tri-
rows of veinal setae, and the costal setae
chome on outer apical margin on III often
are as long as the width of wing at mid-
appearing simple, that on IV ventral and
length; abdominal tergites lack a postero-
forked. Head with 3 ocelli; 3 pairs of ocel-
marginal flange; and small discal setae are
lar setae; 2 pairs of postocular setae be-
present on the pleurotergites. The gland in
tween posterior part of eyes; eyes with 6
abdominal segment III of males opens in a
pigmented facets; maxillary palpi 3-seg-
small orifice in a slightly differentiated
mented. Legs with 2 segmented tarsi. Pro-
area on anterior medial part of the sternite
notum rectangular; with 1 pair of well de-
(Fig. 9). In Baileyothrips, the pronotum
veloped posteroangular setae; occasional
lacks developed posteroangular setae; fore-
macroptera with additional developed, outer
wing has short, intermittent setae on the
posteroangular setae. Mesonotum with sub-
distal half of the forevein, and short costal
median setae slightly caudad of lateral se-
setae are about 4 as long as width of wing
tae. Mesosternal spinula weakly developed.
at midlength; abdominal tergites each have
Brachyptera with short, oval forewings with
a posteromarginal flange with teeth later-
a few marginal and veinal setae; macroptera
ally; and pleurotergites lack discal setae.
with two complete rows of veinal setae, an-
The gland in abdominal segment III of
terior and posterior fringe cilia straight. Ab-
males opens into a orifice at the anterior
domen with median setae long on tergites
part of an elliptical, reticulated glandular
II(cid:8212)VIII, close-set on tergite Il and succeed-
area on the sternite (Kono and O(cid:8217)Neill
ingly longer and farther apart posteriorly;
1964).
posteromarginal flange absent; ctenidia ab-
Xerothrips will run to Oxythrips in cou-
sent; tergite VIII with well developed pos-
plet 34 of the generic key in (cid:8220)The Thrips
teromarginal comb. Sternites IIJ-VII with
of Illinois(cid:8221) by Stannard (1968:275). Xe-
discal setae and each with 3 pairs of pos-
rothrips has a posteromarginal comb on ab-
teromarginal setae.
dominal tergite VIII which is absent from
Male: Abdominal tergite [X with bristle-
Oxythrips. Macroptera having well devel-
like setae; sternites without glandular areas; oped outer posteroangular setae will key to
segment III with internal gland (Fig. 9). Taeniothrips in couplet 36 in Stannard
Etymology.(cid:8212)Generic epithet is a com-
(1968). However, these setae are shorter
bination of the Greek (cid:8220)(cid:8216)Xero(cid:8221)(cid:8217) (dry) and the and more slender than the inner posteroan-
common name of order (cid:8220)(cid:8216)thrips.(cid:8221)(cid:8221) This ge- gular setae and usually are only as long as
nus is known from the Mohave Desert and some posteromarginal setae. Thus, the outer
central valley of California. setae of the macroptera are not typical pos-
Comments.(cid:8212)Brachyptera and macrop- teroangular setae. The two genera differs as
tera closely resemble the two members of follows: In Taeniothrips, two pairs of ocel-
Baileyothrips, arizonensis (Morgan) and lar setae are on the head, median pair of
limbatus (Hood), in having 8-segmented abdominal tergal setae are short and far
antennae, two pairs of postocular setae be- apart, and abdominal sternites of males
tween posterior margin of eyes, six pig- have glandular areas. In Xerothrips, three
mented facets on each eye, forewing with pairs of ocellar setae are on the head, and
fringe cilia straight, long median pair of ter- abdominal tergal median setae are long
gal setae on abdomen, additional discal se- with those on anterior tergites close to each
tae on posteromargins of sternites, and the other.
210 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
Xerothrips dissimilis Nakahara, Basantra spinulose; ferna fused; prospinas-
NEW SPECIES ternum rather wide, with tuberculate pos-
teromedial spina. Mesonotum. Without an-
Female (brachypterous): Body yellow-
teromedial campaniform sensilla. Mesoster-
ish brown; tarsi yellow, tibiae and femora
nal anteromedial process inserts into spina
yellow basally and distally, yellowish
of prospinasternum. Metanotum (Fig. 4).
brown medially; ocellar crescents gray-
Completely reticulated, without campani-
brown; setae pale yellow; antennae yellow
form sensilla. Median setae proximal or
with apices of IIJ-IV pale brown, distal 4%
posterior of anterior margin, 15 (12-15) wm
of V brown, VI brown, paler in basal %,
long; lateral setae 15 (17(cid:8212)20) pm long.
VII-VIII brown.
Forewing: Oval, extending posteriorly
Antenna (Fig. 1): About 2.2 times longer
about length of metanotum, apical margin
than head; segment III oval, 1.5 (1.5(cid:8212)1.6)
broadly arched; with few marginal and
times longer than wide; IV oval, 1.35 (1.2(cid:8212)
veinal setae.
1.3) times longer than wide, apex about %
Abdomen (Fig. 5): Tergites completely
as wide as segment (Fig. 1b), barely ex-
sculptured, rather sparsely striated, with 5(cid:8212)
tending distal of base of ventral trichome;
6 striae medially on tergites [V(cid:8212)VII. Me-
VI not pedicelate at base; forked trichome
dian setae on tergite VII 52 (50-62) pm
on III on outer apical margin (Fig. la), one
long, on VIII 47 (44(cid:8212)50) wm long (Fig. 5a).
fork of trichome often oriented dorsad so
Posteromarginal comb complete on tergite
other fork appears as simple trichome; ven-
VIII (Fig. 5c), close-set, more slender and
tral forked trichome on IV about 10 pm
shorter microtrichia between more devel-
long; inner sense cone of VI in distal 4 of
oped ones, longest 15 (10(cid:8212)15) pm long.
segment, and 15 wm long (Fig. Ic).
Microtrichia on sculpture lines submargin-
Head (Fig. 2): Wider than long, cheeks
ally (Fig. 5b) and between median setae on
slightly arched, shorter than length of eyes,
tergites VI(cid:8212)-VII, throughout tergite VIII,
ocellar area slightly raised. Ocellar setae I
median ones on VI-(cid:8212)VIII longest, a few
anterior of fore ocellus (Fig. 2a), about 12
minute teethlike microtrichia submarginally
zm long, setae II anterolaterad of fore ocel-
present or absent on tergites VI(cid:8212)VII. Ter-
lus (Fig. 2b), near mesal margin of eye,
gite IX with short D1 setae, 2 pairs of cam-
about 7 wm long, ocellar setae III between
paniform sensilla, posterior pair near B1 se-
anterior and posterior ocelli (Fig. 2c), about
tae; B1 setae 52 (42-54) wm long, shorter
(15) pw long. Postocular setae between eyes than tergite X, B2 setae longer than B1 and
(Fig. 2d): 1 pair behind hind ocelli about 7 B3 setae, and 67 (59-74) wm long, B3 setae
wm long, second pair near margin of eyes 57 (50-54) wm long. Tergite X slightly lon-
about 10 pw long, occasionally 1 or 3 pairs ger than IX, divided in posterior % by dor-
present; 2 pairs behind eyes near lateral sal split; dorsal campaniform sensilla near
margin of head. Sculpture of occiput trans- base of B1 setae, in posterior ¥; of tergite;
verse, Striae rather far apart. Mouthcone B1 setae 47 (47-52) wm long, B2 setae 52
conical, about 1.25 times longer than head, (47-52) wm long. Sternite I with 4 minute
and reaching posterior margin of proster- anteromedian setae. Sternites II(cid:8212)VII with
num. short discal setae (Fig. 6d), 19 (16-19) on
Pronotum (Fig. 3): Wider than long, VII, and several on posterior margins. B1(cid:8212)
about 1.5 times longer than head, disc B3 setae on sternites III(cid:8212)VII on posterior
weakly sculptured transversely. Discal setae margin (cf. Fig. 6a(cid:8212)6c). Ovipostior well de-
short; posteroangular setae 27(cid:8212)30 (22-35) veloped, 227 (203-225) wm long. Pleuro-
wm long (Fig. 3a), %(cid:8212)%,) as long as prono- tergites IIJ(cid:8212)VII with 2(cid:8212)4 discal setae.
tum; 4(cid:8212)8 posteromarginal setae (Fig. 3b), Female (macropterous): Light brown
median pair longest, 12 (12(cid:8212)15) wm long. with light orange internal pigments; all tarsi
VOLUME 98, NUMBER 2
211
Figs. 1-5. Xerothrips dissimilis brachypterous female. 1, Antenna (a, forked trichome on segment III posi-
Itli;o nce,d oclaetlelraard ; sebt,a aIpe;x do,f psoesgtmoecnutla rI V;s etca,) . sen3,s e Prcoonneo tuomn s(ea,g mpeonstt erVIo)a.n gu2,l aHre adse ta(;a , bo,c eplolasrt ersoetmaa rIg;i nba, l ocesleltaare ).s et4a,
Mceotmabn ootnu mt.e rg5i,t eA bVdIIoIm)i. nal tergites VII and VIII (a, median seta; b, submarginal microtrichia; c, posteromarginal
212 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
NN
N (cid:8212) C(cid:8212)O (cid:8212)~(cid:8212)Sh
aw
7
Figs. 6-9. Xerothrips dissimilis. 6, Abdominal sternite VI of brachypterous female (a, B1 seta; b, B2 seta;
c, B3 seta; d, discal setae). 7, Forewing of macropterous female. 8, Abdominal tergite IX of male (a, D1 seta;
b, B1 seta; c, B2 seta; d, B3 seta; e, posterolateral seta; f, campaniform sensillum). 9, Internal gland in abdominal
sternite III of male. Scale = 0.1 mm.
yellow, tibiae and femora yellowish brown Pronotum: Posteroangular setae 47 wm
with apices lighter; forewings light brown; long, about % as long as pronotum; occa-
major setae brown; antennae light brown sional specimens with additional (outer)
with median part of segment III paler pair of posteroangular setae developed, 30-(cid:8212)
brown. 35 wm long, more slender and shorter than
Similar to brachyptera in most structural inner pair, about as long as some postero-
characters. marginal setae.
VOLUME 98, NUMBER 2 213
Forewing (Fig. 7): Pointed apically, macropterous females in microns. Body
573-722 wm long, about 47-57 wm wide length 996-1050. Antenna: Total length
at midlength; 19(cid:8212)25 costal setae, about 44 221(cid:8212)226; length and (width) of segment I
ym long at midlength, slightly shorter than 20(22-24), If 32 (24), III 35(cid:8212)37(1 7-22), IV
width of wing; 9-15 anterior fringe cilia; 30(cid:8212)31(17(cid:8212)20), V 32(cid:8212)35(17), VI 45(cid:8212)47(17),
16(cid:8212)22 setae in complete row on forevein, VII 8(cid:8212)-10(6(cid:8212)7), VIII 16(cid:8212)17(5).
10(cid:8212)16 setae on hindvein. Scale with 5 mar- Measurements of body and antenna of
ginal and 1 discal setae. brachypterous male in microns. Body
Abdomen: Posteromarginal comb on ter- length 950 (distended). Antenna: Total
gite VIII with microtrichia 15(cid:8212)20 pm long, length 157; length and (width) of segment
longer than on brachyptera. Ovipositor I 15@0), I 27(21), Il 2516), TV 2117),
178(cid:8212)190 wm long, shorter than on brachyp- V 22(18), VI 32(15), VII 5(7), VIII 10(5).
tera. Type material.(cid:8212)Holotype brachypterous
Male (brachypterous): Similar to but 2 (USNM), 19 brachypterous 2 paratypes:
shorter than female brachyptera. Abdominal Mojave, Kern Co., California, Eriastrum
tergite VIII with posteromarginal comb of densifolium subsp. mohavense (T. T. Craig)
microtrichia. Abdominal tergite IX with Mason, I-31-68, T. R. Haig (CDA 68B2)
bristlelike setae (Fig. 8); D1 setae 12 pm (CDFA, USNM). Brachypterous paratypes.
long (Fig. 8a), anterolaterad of B1 setae and California: 4 mi. east of Monolith (Kern
farther apart than distance between B2 se- Co.), 86 2, 3 6, Eriastrum densifolium
tae; B1(cid:8212)B2 setae in arched line (Fig. 8b, subsp. mohavense, 17-1X-66, T. R. Haig
8c), Bl and B2 setae 17(cid:8212)27 pm long, B3 (CDFA, FSCA, INHS, NHM, SME UCD,
setae 12 pm long (Fig. 8d), between B2 UCR, USNM). Macropterous ¢ paratypes.
seta and posterolateral seta (37 wm long) California: Davis (Yolo Co.), 1, Quercus
(Fig. 8e); campaniform sensilla between B1 agrifolia Nee, 22-X-52, E. I. Schlinger
and B2 setae, another pair anterolaterad of (UCD); 1, under grape vine bark, 16-I-39,
D1 setae (Fig. 8f). Sternites VIII with S. E Bailey (UCD); Porterville (Tulare Co.,
discal setae; abdominal segment III with in- 1, in lichen on fig tree, 16-I-36, E. Baker
ternal gland that opens through a small or- (UCD); Upper Lake (Lake Co.), 1, sweep-
ifice in slightly differentiated area near an- ing grass on ditch bank, 14-V-47, S. FE Bai-
teromedial margin of sternite (Fig. 9). ley (UCD). Nevada: Mercury (Nye Co.), 2,
Measurements of body and antenna of PHA.VAL., 12m(HF)-242, CDJ, 24-V-62
brachypterous female in microns. Measure- (INHS). Other examined macropterous 2 2.
ments of holotype given first followed by California: Coarsegold (Madera Co.), 8,
those of paratypes in parenthesis. Body Tillandsia sp., 9-XII-93, B. Rohn and A.
length 1136 (1160-1260) (distended). An- Espinosa (USNM).
tenna: total length 191 (183-192); length Distribution.(cid:8212)United States (CA, NV).
and width of segment I 17(17), 22(22(cid:8212)24); Hosts.(cid:8212)Eriastrum densifolium subsp.
II 30(27-(cid:8212)32), 22(22(cid:8212)23); Ill 30(30), 201 8(cid:8212) mohavense (T. T. Craig) Mason, grass, Quer-
20); IV 27(24(cid:8212)27), 20(20); V 30(27-30), cus agrifolia Nee, Tillandsia sp., Vitis sp.
18(20); VI 38(35-37), 17117); VII 7(6-7), Etymology.(cid:8212)Specific epithet based on
7(7); VII 12(12(cid:8212)15), 5(5(cid:8212)6). Head length Latin (cid:8220)(cid:8216)dissimilis,(cid:8217)(cid:8217) meaning unlike. Males
86, width at eyes 111 (101-117), width at of this species have an unusual, internal or-
cheeks 119 (111-128); eye length 50, width gan in abdominal segment III with a small
35 (35-37); mouthcone length 109 (106(cid:8212) orifice on the sternite.
109); pronotum length 109 (111-124), Comments.(cid:8212)Brachyptera are known
width 161 (161-180); length of tergite IX only from Kern Co., California; whereas
54 (54-57); length of tergite X 62 (62-64). the macroptera were collected from differ-
Measurements of body and antenna of ent localities in California and Nevada. The
214 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
males are brachypterous and known only of Alberta, Edmonton; and M. E. Schauff,
from the two populations in Kern Co. Systematic Entomology Laboratory, Wash-
Thrips are not normally stained. How- ington, D.C. The illustrations were prepared
ever, a cleared and stained specimen was by L. H. Lawrence, staff artist, Systematic
selected as the holotype because most of the Entomology Laboratory.
structural characters of the unstained spec-
imens could not be observed clearly. The LITERATURE CITED
coloration is based on the unstained para- Beshear, R. J. and J. O. Howell. 1976. A new species
types. of Pseudothrips, with a key to the North American
Species. Annals of the Entomological Society of
ACKNOWLEDGMENTS America 69(6): 1082-1084.
Kono, T. and K. O(cid:8217)Neill. 1964. The new generic sta-
I thank the following curators for loan of
tus and synonymy of Anaphothrips arizonensis
specimens: L. Kimsey, UCD; T. Kono, for- Morgan, with the description of the male (Thysa-
mer thysanopterist with CDFA; and K. noptera, Thripidae). California Department of Ag-
Methven, INHS. I also thank the following riculture, Bureau of Entomology Occasional Pa-
pers 61-4.
colleagues for their reviews of the manu-
Stannard, L. J. 1968. The Thrips, or Thysanoptera, of
script and constructive comments: H. A.
Illinois. Illinois Natural History Survey Bulletin
Denmark, FSCA; B. S. Heming, University 29(4): 215-552.