Life history and descriptions of adults and immature stages of aciurina semilucida (bates) (diptera: tephritidae) on chrysothamnus viscidiflorus (hooker) nuttall in southern California

15 Pages·1996·10.4 MB·

PROC. ENTOMOL. SOC. WASH.
98(4), 1996, pp. 752-766
LIFE HISTORY AND DESCRIPTIONS OF ADULTS AND IMMATURE
STAGES OF ACIURINA SEMILUCIDA (BATES) (DIPTERA: TEPHRITIDAE)
ON CHRYSOTHAMNUS VISCIDIFLORUS (HOOKER) NUTTALL IN
SOUTHERN CALIFORNIA
RICHARD D. GOEDEN AND JEFFREY A. TEERINK
Department of Entomology, University of California, Riverside, CA 92521, U.S.A.
Abstract.(cid:8212)Aciurina semilucida (Bates) is a rare, highly localized, tephritid fly forming
pubescent, axillary bud galls on branches of Chrysothamnus viscidiflorus (Hooker) Nuttall
in southern California. Documentation is provided that the wing patterns of the adults are
very strongly sexually dimorphic in southern California, but much less dimorphic in some
other parts of its range, e.g. in Idaho, where it previously has been reported only from C.
nauseosus (Pallen) Britton. The egg, first-through third-instar larvae, and puparium are
described, illustrated, and compared with other southern California Aciurina spp. The egg
has a long pedicel, with a knoblike anterior apex. The second and third instars have
abdominal terga IIJ(cid:8212)V expanded into a dorsal ambulatory lobe. This ambulatory lobe and
the large open gall cavity within which the larva feeds are characteristics shared only
with A. michaeli Goeden among southern California Aciurina spp. studied to date.
Key Words: Insecta, Aciurina, Chrysothamnus, biology, galls, regional sexual dimor-
phism, adult taxonomy, immature taxonomy, parasitoids
Six Aciurina spp. (Diptera: Tephritidae) urina species ...(cid:8221) (Foote et al. 1993). In-
forming galls on Chrysothamnus or Bac- stead, A. semilucida (Bates) is the rare, lo-
charis spp. (Asteraceae) in southern Cali- calized, and distinct species in California
fornia have been studied by us to date. This that we describe herein.
paper follows those on A. thoracica Curran
(Headrick and Goeden 1993), A. ferruginea MATERIALS AND METHODS
(Doane), A. michaeli Goeden (Goeden and
Our field studies were conducted on
Teerink 1996a), and A. idahoensis Steyskal
Chrysothamnus viscidiflorus (Hooker) Nut-
(Goeden and Teerink 1996b), in a series tall (Asteraceae) at three locations in Deep
projected to end with A. trixa Curran [as
Spring Valley, the southernmost extension
interpreted and reinstated by Dodson and of the Great Basin biome (Munz 1974, Hall
George (1986)], which is the most common 1991), located northeast of the Westgard
species of Aciurina in California (D. H. Pass in the White-Inyo Mountain Range,
Headrick, RDG, and JAT, unpublished Inyo Co., California. Galls containing lar-
data). Steyskal (1984) erroneously synony- vae and puparia of A. semilucida were sam-
mized A. semilucida (Bates) with A. bige- pled from plants in Payson Canyon at 1770
loviae (Cockerell) and A. trixa (Dodson and m at the southwest end of the Valley, north
George 1986) to make A. bigeloviae (cid:8220) of Deep Spring Lake at 1720 m towards the
the most widely distributed and most vari- center of the Valley, and above Antelope
able of all the Chrysothamnus-feeding Aci- Spring at 1695 m on the north side of the
VOLUME 98, NUMBER 4 V3
Valley during March and April, 1993 and modified by Dodson and George (1986).
1994. Excised galls were transported in Morphological terminology and telegraphic
cold-chests in an air-conditioned vehicle to format used to describe the immature stages
the laboratory and stored under refrigera- follow Headrick and Goeden (1993) and
tion for subsequent dissection, photogra- Goeden and Teerink (1996a, b) and our ear-
phy, description, and measurement. Two lier works cited therein. Means + SE are
first-instar, five second-instar, and 18 third- used throughout this paper. Voucher speci-
instar larvae and two puparia dissected mens of reared adults of A. semilucida re-
from galls were preserved in 70% EtOH for side in the research collection of RDG; pre-
scanning electron microscopy (SEM). All served specimens of eggs, larvae, and pu-
other fully grown larvae and puparia were paria are stored in the research collection of
placed in separate, glass shell vials stop- JAT.
pered with absorbant cotton and held in hu-
midity chambers at room temperature for RESULTS AND DISCUSSION
adult and parasitoid emergence. Specimens
Taxonomy
for SEM later were hydrated to distilled wa-
ter in a decreasing series of acidulated Adult.(cid:8212)Aciurina semilucida was de-
EtOH. They were osmicated for 24 h, de- scribed (as a Tephrella) by Bates (1935)
hydrated through an increasing series of from five males and seven females reared
acidulated EtOH, critically point dried, from galls on Chrysothamnus (as Bigelovia)
mounted on stubs, sputter-coated with a sp. from Riparia, Washington. The host
gold-palladium alloy, and studied with a plant of A. semilucida was further identified
JEOL JSM C-35 SEM in the Department of as C. nauseosus (Pallen) Britton in Idaho
Nematology, University of California, Riv- by Novak et al. (1967). Curran (1932)
erside. erected the genus Aciurina and designated
Most adults reared from isolated puparia the type species as A. trixa. Steyskal (1984)
were individually caged in 850-ml, clear- synoptically revised the genus, and Foote et
plastic, screened-top cages with a cotton al. (1993) adopted his revision, which syn-
wick and basal water reservoir and provi- onymized both A. trixa and A. semilucida
sioned with a strip of paper toweling im- with A. bigeloviae. Unfortunately, Steyskal
pregnated with yeast hydrolyzate and su- (1984) and Foote et al. (1993) were un-
crose. These cagings were used for longev- aware that several North American species
ity studies and oviposition tests in the in- of Aciurina have sexually dimorphic wing
sectary of the Department of Entomology, patterns, e.g. A. ferruginea, A. michaeli, and
University of California, Riverside, at 25 + A. idahoensis (Goeden and Teerink 1996a,
1°C, and 14/10 (L/D) photoperiod. Virgin b, unpublished data). Furthermore, A. ida-
male and female flies obtained from emer- hoensis shows regional variation in this di-
gence vials as well as field-swept adults morphism, i.e. being strongly dimorphic in
were paired in clear-plastic petri dishes pro- California, but less so in Idaho (Goeden and
visioned with a flattened, water-moistened Teerink 1996b).
pad of absorbant cotton spotted with honey Before redescribing the adults of what
(Headrick and Goeden 1991) for direct ob- we believe are A. semilucida in California,
servations, videorecording, and _ still-pho- we provide our reasons for identifying them
tography of their courtship and copulation as such. First, A. semilucida was reported
behavior to be reported elsewhere (Head- by Wangberg (1981) from galls on C. nau-
rick and Goeden, unpublished data). seosus similar to those found by us on C.
Plant names used in this paper follow viscidiflorus in California; however, in Ida-
Munz (1974); tephritid nomenclature and ho, A. semilucida, like A. idahoensis (Goe-
terminology follow Foote et al. (1993) as den and Teerink 1996b), is much less sex-
754 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
ually dimorphic. Steyskal (1983) believed much different wing pattern (i.e. the Cali-
that A. semilucida (cid:8220)(cid:8216)... was no more than fornia population has strongly sexually di-
A. bigeloviae with a strongly reduced wing morphic wing patterns). The wing pattern
pattern.(cid:8221)(cid:8217) Accordingly, he synonymized A. of these southern California females (Fig.
semilucida with A. bigeloviae, along with 1F) is similar to that of A. Jutea (Coquillett)
A. trixa, the resulting species representing as pictured and described in Steyskal
what he termed *... the most widely dis- (1984) and Foote et al. (1993). Aciurina lu-
tributed and most variable of all the Chrys- tea is a rare but widely distributed species
othamnus-feeding species, that is, the typi- that has been reported only from C. visci-
cal group of Aciurina.(cid:8221)(cid:8217) Dodson and George diflorus (Wangberg 1981, Steyskal 1984,
(1986) concluded, however, that A. trixa is Foote et al. 1993). However, in both female
a separate and distinct species forming California A. semilucida and A. lutea nei-
smooth galls on C. nauseosus; whereas, A. ther hyaline mark in cell m crosses vein M
bigeloviae forms (cid:8220)(cid:8216)cottony(cid:8221) galls on this (Fig. 1F), as does the apical mark in A. bi-
same host plant. Neither A. bigeloviae nor geloviae and A. trixa (Headrick, RDG, and
A. trixa apparently exhibited sexually di- JAT, unpublished data). Furthermore, A. L.
morphic wing patterns, although consider- Norrbom (1996, in litt.) reports that three
able wing pattern variation was reported af- males of A. lutea in the U.S. National Mu-
ter extensive field and laboratory studies by seum collection (from northern California,
Dodson and George (1986) in Arizona, Nevada, and Utah) have the same wing pat-
Colorado, New Mexico, and Utah. How- tern as the female holotype (i.e. like Foote
ever, only A. trixa apparently occurs on C. et al. 1993, Fig. 115), and thus are quite
nauseosus in California, as no cottony galls different from California males of A. sem-
of A. bigeloviae have ever been found on ilucida. Moreover, A. semilucida has a
this widely distributed host plant extensive- densely gray microtrichose scutum with
ly studied by us throughout its range in white to yellow, stout setulae (see below);
southern California (D. H. Headrick, RDG, whereas, these three A. /utea males have a
and JAT, unpublished data). Only A. trixa mostly bare, shiny scutum with slender,
was reared from smooth galls on C. nau- black setulae (Norrbom, in litt., 1996).
seosus at our study site, where A. semilu- Also, in A. lutea, the subapical hyaline spot
cida was found only on C. viscidiflorus. in cell dm touches or approaches vein M,
Figure 1A and 1B respectively show the but is well isolated from vein CuA, (Norr-
right wings typical of voucher specimens of bom, in litt., 1996); whereas, cell dm touch-
male and female A. semilucida reared from es CuA, in A. semilucida (see below). Fi-
galls on C. nauseosus collected from near nally, Wangberg (1981) pictured and de-
Lewiston, Nez Perce Co., Idaho, where scribed the gall of A. /utea as a simple, but
Wangberg (1981) studied this species. Fig- abrupt, woody swelling with thickened
ure 1C and 1D respectively depict a male walls on older stems as well as current
and female with the more darkly patterned year(cid:8217)s stem growth. Thus, its reported gall
condition and the variation found among is definitely different from that which we
these same voucher specimens examined describe below.
from Idaho. Compare the aforementioned Knowing now that sexually dimorphic
wing patterns with those of a male (Fig. 1E) wing patterns occur in some species of Aci-
and female (Fig. 1F) that we call A. semi- urina (Goeden and Teerink 1996a, b), and
lucida reared from similar galls on C. vis- that this dimorphism may occur or nearly
cidiflorus in southern California. The wing be absent within different parts of the range
patterns of the males from California and of a single species (Goeden and Teerink
Idaho compare favorably; whereas, the fe- 1996b), we conservatively chose to identify
males from southern California have a the flies with which this paper is concerned
VOLUME 98, NUMBER 4 WD
F
E
Fig. 1. Right wings of Aciurina semilucida. (A) Light form of male from Idaho; (B) light form of female
from Idaho; (C) dark form of male from Idaho; (D) dark form of female from Idaho; (E) male from California;
(F) female from California.
as A. semilucida. Accordingly, males (Fig. terns found among both males and females
1A, 1C) and females (Fig. 1B, 1D) of A. of A. semilucida from Idaho (Fig 1A(cid:8212)D),
semilucida examined from Idaho and males but only among males (Fig. 1E) from Cal-
from California (Fig. 1E) generally appear ifornia. Similarly, the most hyaline wing
like the two most hyaline wing patterns pattern of the three patterns for A. bigelov-
(>50% hyaline) among the four patterns il- iae illustrated by Foote et al. (1993, Fig.
lustrated for A. bigeloviae by Steyskal 124) is generally illustrative of the wing
(1984, Fig. 15-16). Put another way, these patterns of males and females of A. semi-
two illustrations in Steyskal (1984) respec- lucida from Idaho and the males from Cal-
tively represent the light and dark wing pat- ifornia. This suggested relabeling parallels
756 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
that applicable to the wing pattern of male setulae or absent; one postsutural dorsocen-
A. idahoensis from California, which close- tral slightly posteriorad of pre-sutural su-
ly resembles that illustrated for A. notata in pra-alar, at half the distance to the supra-
Steyskal (1984) and Foote et al. (1993) [but alar bristle; two notopleurals; one each of
see discussion in Goeden and Teerink post-alar, intra-alar, and acrostical; scutel-
(1996b) of inconsistencies between pub- lum with one basal, prominent, scutellar
lished reports on A. idahoensis and A. no- bristle; katepisternal bristle well developed.
tata|. The males of A. idahoensis from Cal- Coxae, femora, tibiae, and tarsi yellow; fore
ifornia and males of A. semilucida both femur, unlike male, unthickened, but also
have reduced wing patterns and mostly hy- bearing loose (cid:8220)(cid:8216)comb(cid:8221) of long, anteroven-
aline wings, but are readily separated by the tral setae. Wings (Fig. IF) mostly dark
much more reduced pattern in the wings of brown, with marginal hyaline incisions and
the former males (Goeden and Teerink internal marks as follows: cell be wholly
1996b). yellow; cell c with basal and median dark
Females from California(cid:8212)(cid:8212)Apparently, or hyaline spots, if the latter, also with
females of A. semilucida in southern Cali- small, apical, marginal hyaline incision; cell
fornia have a wing pattern (Fig. 1F) that r, with one or two hyaline spots along cos-
heretofore has neither been recognized nor ta, if one, the spot extending halfway across
described. Or they have been subsumed un- cell r,, if two, the proximal spot extending
til now, like other species noted above, as to vein R,,3, the distal spot across cells r,
one of the dark patterned wing forms of A. and r,,3, to vein R,,; (Fig. 1F) or across r,,
bigeloviae or, conceivably, A. lutea, as dis- r>,, and r,,, to vein M; cell r,,; with a dis-
tinguished and illustrated by Steyskal tinct bulla; cell dm with prominent preapi-
(1984) and Foote et al. (1993). The follow- cal hyaline spot touching both veins M and
ing description of the California form of A. CuA,, just CuA,, or neither vein; cell m
semilucida female is based on three females with median, hyaline, wedge-shaped mark
individually reared from galls collected at reaching or nearly reaching anteriorly-
our Payson Canyon study site. Figure 1F is bowed vein M and_ sub-basal, hyaline,
a photograph of the right wing excised from wedge-shaped spot half as long; vein dm-cu
one of these three females. bowed apicad; cell br with prominent
Head: White with golden yellow anten- preapical spot; cell cua, with one or two
nae, frons, and ventral occiput. Three pairs marginal hyaline incisions, apical incision
of frontal bristles, basally yellow, light absent or reaching CuA, and contiguous
brown distally; two pairs of orbital bristles, with preapical spot in cell dm, and promi-
the anterior pair light brown, posterior pair nent basal incision starting basad of and
light yellow; inner vertical bristles and crossing vein A,+CuA, and extending an-
ocellar bristles well developed and light teriorly to or nearly to CuA,; alula and ad-
brown; other bristles wholly or basally jacent base of anal lobe hyaline.
white or light yellow. Abdomen: Shiny, reddish-brown, except
Thorax: Dark brown, mesonotum cov- for tergite 6, which may be dark brown,
ered with fine grey pollinosity and many, oviscape shiny black; tergum sparsely cov-
prominent, pale to golden yellow setulae ered with fine, light yellow setulae.
posteriorad as far as and including all but Males and Idaho females.(cid:8212)The wings of
shiny, posterior margin of dark brown or 12 males of A. semilucida examined from
black scutellum. Mediotergite black, shiny California and 40 males and 20 females ex-
medially, grey pollinose dorsally and later- amined from Idaho characteristically are
ally. All of the following paired bristles are >50% hyaline (Fig. 1A(cid:8212)E), and are de-
present and yellow-brown: One postprono- scribed here collectively: Cell be wholly
tal; scapular bristles indistinguishable from hyaline; cell c wholly hyaline or yellow or
VOLUME 98, NUMBER 4 ST
with a small central brown spot; brown or longated dorsal petals dorsad of mouth lu-
yellow-brown band covering veins bm(cid:8212)cu men (Fig. 2B-2); paired dorsal sensory or-
and r(cid:8212)m; apices of cells r,,, and r,4,5 nar- gans dorsomediad of anterior sensory lobes,
rowly brown; brown spot arising midway each consisting of dome-shaped papilla
on vein CuA,; usually brown crossband (Fig. 2B-3, 2C-1); anterior sensory lobes
running from apex of cell r, across vein bear terminal sensory organ (Fig. 2C-2), pit
dm-cu, varying in width, sometimes inter- sensory organ (Fig. 2C-3), lateral sensory
rupted in cell r,,,, or more commonly, bro- organ (Fig. 2C-4), and supralateral sensory
ken or attenuated at or before vein M. organ (Fig. 2C-5); stomal sense organs ven-
These spots connected or variously embel- trolaterad of anterior sensory lobes (Fig.
lished in darker wing patterns (Fig. IC, 2D-1); lateral sensillum located laterad of
11D): anterior sensory lobe (Fig. 2B-4); ventro-
Immature stages.(cid:8212)Egg: Fifteen ova of A. lateral sensillum ventrolaterad of stomal
semilucida were white, opaque, smooth; sense organ (Fig. 2D-2); mouth hooks bi-
with an elongate-ellipsoidal body, 0.52 + dentate, teeth conical (Fig. 2D-3); median
0.007 (range, 0.46(cid:8212)0.56) mm long, 0.21 = oral lobe laterally flattened, tapering api-
0.008 (range, 0.16(cid:8212)0.26) mm wide, smooth- cally (Fig. 2D-4); prothorax smooth, minute
ly rounded at tapered posterior end; with an acanthae ventrally (Fig. 2B-5); anterior tho-
elongate, anterior pedicel, 0.25 + 0.008 racic spiracles dorsolaterad on posterior
(range, 0.20(cid:8212)0.30) mm long, 0.03 (range, margin of prothorax with three oval papil-
0.02(cid:8212)0.04) mm wide medially, and 0.05 lae (Fig. 2E); metathoracic lateral spiracular
(range, 0.04(cid:8212)0.06) mm wide at knoblike, complex consists of an open spiracle (Fig.
anterior apex. ~ 2F-1), and two verruciform sensilla (Fig.
The eggs of A. semilucida are stalked 2F-2); abdominal lateral spiracular complex
like those of A. ferruginea and A. michaeli consists of an open spiracle and a single
(Goeden and Teerink 1996a) and A. ida- verruciform sensillum; caudal segment
hoensis (Goeden and Teerink 1996b), all bears the posterior spiracular plates (Fig.
four of which differ greatly in appearance 2G); posterior spiracular plates with three
from the short-pedicelled, partly reticulated oval rimae, ca. 0.042 mm in length (Fig.
egg of A. thoracica (Headrick and Goeden 2G-1), and four interspiracular processes,
1993). The respiratory function of the elon- longest measuring 0.01 mm (Fig. 2G-2);
gate pedicel of these eggs was first sug- compound sensilla ventrad of posterior spi-
gested for A. michaeli by Tauber and Taub- racular plates consist of a stelex sensillum
er (1967) and was supported with morpho- (Fig. 2H-1) and a verruciform sensillum
logical and biological data by Goeden and (Fig. 2H-2); stelex sensilla surround margin
Teerink (1996a). The egg bodies and pedi- of caudal segment in 2-dorsal, 4-ventral ar-
cels of A. idahoensis and A. semilucida are rangement.
shorter on average than these parts of the Aciurina semilucida closely resembles A.
eggs of both A. ferruginea and A. michaeli michaeli in general, third-instar habitus
(Goeden and Teerink 1996a, b), with A. (Goeden and Teerink 1996a). Both species
semilucida having the shortest pedicel of are enlarged dorsally and have a distinct
the three species. hump, which differentiates them from other
Third instar: Superficially smooth, pyri- Aciurina species studied thus far, i.e. A.
form, tapering anteriorly, truncated poste- thoracica (Headrick and Goeden 1993), A.
riorly, abdominal segments III-V enlarged ferruginea (Goeden and Teerink 1996a), A.
dorsally, minute acanthae ventrally (Fig. idahoensis (Goeden and Teerink 1996b)
2A); gnathocephalon conical, rugose pads and A. trixa, (Goeden, unpublished data).
mediad of anterior sensory lobes and later- Aciurina semilucida and A. michaeli are
ad of mouth lumen (Fig. 2B-1); pair of en- very similar in the types, sizes, and place-
15KU 446
@
be kul, x veoe.
KU ¥Abo Saal 1
Fig. 2. Third instar of A. semilucida. (A) Habitus, anterior to left; (B) gnathocephalon, anterior view, 1(cid:8212)
rugose pads, 2(cid:8212)elongated dorsal petals, 3(cid:8212)dorsal sensory organ, 4(cid:8212)lateral sensillum, 5(cid:8212)minute acanthae; (C)
anterior sensory lobe, 1(cid:8212)dorsal sensory organ, 2(cid:8212)terminal sensory organ, 3(cid:8212)pit sensory organ, 4(cid:8212)lateral
sensory organ, 5(cid:8212)supralateral sensory organ; (D) gnathocephalon, ventrolateral view, 1(cid:8212)stomal sense organ,
VOLUME 98, NUMBER 4 759
ment of sensory structures. They do how- terior spiracular plates (Fig. 3F-2) consist
ever, differ in the number of sensilla in the of a stelex sensillum and a verruciform sen-
lateral spiracular complex. Aciurina mi- sillum (Fig. 3H); stelex sensilla surround
chaeli has only one verruciform sensillum margin of caudal segment in 2-dorsal,
in the metathoracic lateral spiracular com- 4-ventral arrangement (Fig. 3F-3).
plex and no sensilla in the abdominal lateral The second instar is enlarged dorsally in
spiracular complex (Goeden and Teerink abdominal segments III(cid:8212)V as in the third
1996a). Aciurina idahoensis which co-oc- instar. The gnathocephalon is similar in
curs with A. semilucida on C. viscidflorus, shape and sensory structures. The anterior
has the same number of sensillum in the thoracic spiracles, lateral spiracular com-
lateral spiracular complex as A. michaeli. plex and the posterior spiracles are consis-
(Goeden and Teerink 1996b). tent between the two instars. The second
Second instar: Superficially smooth, pyr- instar differs slightly from the third in the
iform, minute acanthae ventrally (Fig. 3A); compound sensilla on the caudal segment.
gnathocephalon conical, smooth, rugose One pair in the second instar consists only
pads mediad and laterad of anterior sensory of a stelex sensillum. This was also ob-
lobes (Fig. 3B-1); dorsal petals dorsad of served in A. idahoensis, where the second
mouth lumen (Fig. 3B-2); paired dorsal sen- instar contained only one sensillum in one
sory organs dorsomediad of anterior sen- of the compound sensilla (Goeden and
sory lobes (Fig. 3B-3, 3C-1); anterior sen- Teerink 1996b); A. ferruginea also showed
sory lobes bear the terminal sensory organ slight differences in the compound sensilla
(Fig. 3C-2), pit sensory organ (Fig. 3C-3), in the second and third instars (Goeden and
lateral sensory organ (Fig. 3C-4), and su- Teerink 1996a).
pralateral sensory organ (Fig. 3C-5); stomal First instar: Superficially smooth, ovoi-
sense organs ventrolaterad of anterior sen- dal, minute acanthae circumscribe interseg-
sory lobes, near mouth lumen (Fig. 3B-4, mental lines; gnathocephalon conical,
3C-6); mouth hooks bidentate, teeth conical smooth (Fig. 4A); paired dorsal petals dor-
(Fig. 3B-5); median oral lobe laterally flat- sad of mouth lumen (Fig. 4A-1); dorsal sen-
tened, tapering apically (Fig. 3B-6); protho- sory organs dorsomediad of anterior sen-
rax smooth (Fig. 3B); anterior thoracic spir- sory lobes (Fig. 4A-2, 4B-1); anterior sen-
acles consist of three oval papillae (Fig. sory lobes bear the terminal sensory organ
3D); metathoracic lateral spiracular com- (Fig. 4B-2), pit sensory organ (not ob-
plex consists of an open spiracle (Fig. served), lateral sensory organ (Fig. 4B-3),
3E-1), and two verruciform sensilla (Fig. supralateral sensory organ (Fig. 4B-4); sto-
3E-2); abdominal lateral spiracular complex mal sense organs indistinct, laterad of
consists of an open spiracle and a single mouth lumen (Fig. 4A-3); mouth hooks bi-
verruciform sensilla; caudal segment bears dentate, teeth conical (Fig. 4A-4); median
the posterior spiracular plates (Fig. 3F-1); oral lobe laterally flattened (Fig. 4A-5);
posterior spiracular plates with three oval prothorax smooth; anterior thoracic spira-
rimae, ca. 0.01 mm in length (Fig. 3G-1), cles absent; lateral spiracular complex not
and four blade-like interspiracular process- observed; caudal segment obscured in SEM
es, longest measuring 0.008 mm (Fig. specimens.
3G-2); compound sensilla ventrad of pos- The first instar is not expanded dorsally
<<
2(cid:8212) ventrolateral sensillum, 3(cid:8212)mouth hooks, 4(cid:8212)median oral lobe; (E) anterior thoracic spiracle; (F) metathorax,
lateral spiracular complex, 1(cid:8212)spiracle, 2(cid:8212)verruciform sensilla; (G) caudal segment, posterior spiracular plates,
1(cid:8212)rima, 2(cid:8212)interspiracular process; (H) compound sensillum, 1(cid:8212)stelex sensillum, 2(cid:8212)verruciform sensillum.
PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
Fig. 3. Second instar of A. semilucida. (A) Habitus, anterior to left; (B) gnathocephalon, anterior view, 1(cid:8212)
rugose pads, 2(cid:8212)dorsal petals, 3(cid:8212)dorsal sensory organ, 4(cid:8212)stomal sense organ, 5(cid:8212)mouth hooks, 6(cid:8212)median
oral lobe; (C) anterior sensory lobe, 1(cid:8212)dorsal sensory organ, 2(cid:8212)terminal sensory organ, 3(cid:8212)pit sensory organ,
4(cid:8212)1ateral sensory organ, 5(cid:8212)supralateral sensory organ, 6(cid:8212)stomal sense organ; (D) anterior thoracic spiracle;
VOLUME 98, NUMBER 4 761
as in the third and second instars. The gen-
eral habitus is more ovoid than pyriform.
The gnathocephalon is smooth, lacking ru-
gose pads. The anterior sensory lobes and
stomal sense organs are small and indis-
tinct. The gnathocephalon in A. semilucida
first instars is similar to that of A. ferrugi-
nea and A. idahoensis (Goeden and Teerink
1996a, b).
Puparium: Smooth, elongate-reniform,
reddish-brown (Fig. 5A); anterior end bears
anterior thoracic spiracles (Fig. 5B-1) and
invagination scar (Fig. 5B-2); caudal end
bears posterior spiracular plates; posterior
spiracular plates with three oval rimae, Ca.
0.021 mm in length (Fig. 5C-1), and four
interspiracular processes with 1(cid:8212)3 branches,
longest measuring 0.01 mm (Fig. 5C-2).
Nineteen averaged 3.94 + 0.17 (range,
3.06(cid:8212)4.77) mm in length and 1.93 + 0.07
(range, 1.44(cid:8212)2.34) mm in width.
DISTRIBUTION AND HOSTS
Aciurina semilucida was known only
from its type locality in Washington (Bates
1935) and from Nez Perce Co. in Idaho
Fig. 4. First instar of A. semilucida. (A) Gnatho-
(Wangberg 1981). Although its distribution cephalon, anterolateral view, 1(cid:8212)dorsal petals, 2(cid:8212)dor-
probably parallels those of its known host sal sensory organ, 3(cid:8212)stomal sense organ, 4(cid:8212)mouth
plants, C. viscidiflorus and C. nauseosus, hooks, 5(cid:8212)median oral lobe; (B) anterior sensory lobe,
1(cid:8212)dorsal sensory organ, 2(cid:8212)terminal sensory organ,
both of which are common throughout the
3(cid:8212) lateral sensory organ, 4(cid:8212)supralateral sensory or-
western United States (Munz 1974), it ap-
gan.
parently exists in localized, discontinuous
demes, whose semi-isolation probably fa-
cilitated the strong dimorphism at the ultimately show these southern and north-
southwestern periphery of its distribution in ern flies to be distinct and each to have spe-
southern California reported herein. Aciuri- cialized on only one of these two hosts, as
na semilucida, like A. idahoensis, has only apparently has happened in California with
been found in California at three locations A. ferruginea, A. michaeli (Goeden and
in Deep Spring Valley, which lies close to Teerink 1996a), A. idahoensis (Goeden and
the Nevada border. Alternatively, further Teerink 1996b), and A. semilucida on C.
taxonomic study of the galls, hosts, and viscidiflorus versus A. trixa on C. nauseo-
reared A. semilucida adults from other lo- sus in California (unpublished data). How-
cations in the western United States may ever, oligophagy is known among Aciurina
(cid:8212)
(E) metathorax, lateral spiracular complex, 1(cid:8212)spiracle, 2(cid:8212)verruciform sensilla; (F) caudal segment, 1(cid:8212)pos-
terior spiracular plate, 2(cid:8212)compound sensilla, 3(cid:8212)stelex sensillum; (G) posterior spiracular plate, 1(cid:8212)rima, 2(cid:8212)
interspiracular proeess; (H) compound sensillum, stelex sensillum.