LIFE HISTORY AND DESCRIPTION OF IMMATURE STAGES OF TRUPANEA JONESI CURRAN (DIPTERA: TEPHRITIDAE) ON NATIVE ASTERACEAE IN SOUTHERN CALIFORNIA

15 Pages·1998·4.6 MB·

by  R D Goeden

PROC. ENTOMOL. SOC. WASH
100(1). 1998. pp. 126-140
LIFE HISTORY AND DESCRIPTION OF IMMATURE STAGES OF
TRVPANEA JONESI CURRAN (DIPTERA: TEPHRITIDAE) ON NATIVE
ASTERACEAE IN SOUTHERN CALIFORNIA
Richard D. Goeden, Jeffrey A. Teerink and David H. Headrick
Department of Entomology, University of California, Riverside, CA 92521, U.S.A.
(RDG, e-mail: [email protected]).
—
Abstract. Trtipanea jonesi Curran is a multivoltine, florivorous fruit fly (Diptera: Te-
phritidae) infesting at least 104 species of host plants in 42 genera, eight tribes, and 17
subtribes in California and other western United States. Accordingly, this tephritid is the
species most commonly reared from mature flower heads of native Asteraceae throughout
California. Records for three new host genera and eight new host species are reported. The
egg, first-, second- and third-instar larvae, and puparium are described and figured. The
abdominal, lateral spiracular complex of the third instar consists of a spiracle and a single
placoid sensillum and thus differs from other third instar Tnipanea spp. reported to date.
A subdorsal sensillum on the gnathocephalum is reported for the first time from the third
instar of a Tnipanea. The life cycle of T. jonesi in California is of the aggregative type.
Eggs were laid in closed, preblossom flower heads through or between the overlapping
phyllaries into or between the florets. First and second instars fed on the ovules and florets,
while the third instars principally fed on the soft achenes. The receptacles ofinfested flower
heads were scored (visibly abraided) by the mouth hooks or not depending in part on larval
densities and host-plant species. Infested flower heads in samples from 10 different hosts
contained an average of 1.7 ± 0.1 (±SE) (range, 1-15) puparia and an average total of 80
± 2 (25-119) soft achenes/florets, of which an average of 7.3 ± 0.5 (range, 2-40) soft
achenes/florets, or 16% (range, 1-15%), were damaged by larval feeding. Courtship and
copulation behaviors are described, including a characteristic, unique wing display combin-
ing rapid wing hamation with supination by males approaching females. Male-male combat
using mouthparts and legs also is described. Five species of Hymenoptera were reared from
individual puparia and mature flower heads bearing puparia of T. jonesi as solitary, larval-
pupal endoparasitoids; Eitiytoma obtiisiventris Gahan, E. veronia Bugbee (Eurytomidae),
Halticoptera sp. (Pteromalidae), Mesoplobus sp. (Pteromalidae), and Pteromalus sp. (Pter-
omalidae) Other possible primary parasitoids or hyperparasitoids reared along with T.jonesi
from mature flower heads were Eiipebmis sp. (Eupelmidae), Pachyneiiron sp. (Pteromalidae)
and one, unidentified species each of Cynipidae and Eulophidae.
Key Words: Insecta, Trupanea, Asteraceae, nonfrugivorous Tephritidae, biology, tax-
onomy ofimmature stages, mating behavior, flower-head feeding, host-plant
range, parasitoids
Trupanea jonesi Curran (Diptera: Te- to a genus which occurs worldwide and
phritidae) is the most common species of that is one of the larger and more wide-
indigenous, nonfrugivorous fruit fly en- spread genera ofnonfrugivorous fruit flies
countered in California, belonging itself in North America and California (Foote
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VOLUME NUMBER
100. 1 127
and Blanc 1963, Foote et al. 1993). How- alloy, and studied with a JEOL JSM C-35
ever, being of little or no economic im- SEM in the Department of Hematology,
portance, most species of Trupanea re- University of California, Riverside.
main little known (Foote 1960, Foote et Most adults reared from isolated puparia
al. 1993). Detailed life histories of six were individually caged in 850-ml, clear-
species of Trupanea from southern Cali- plastic, screened-top cages with a cotton
fornia have been published (Cavender and wick and basal water reservoir and provi-
Goeden 1982; Goeden 1987, 1988; Goe- sioned with a strip of paper toweling im-
den and Teerink 1997c; Headrick and pregnated with yeast hydrolyzate and su-
Goeden 1991; Knio et al. 1996b), and the crose. These cages were used for longevity
immature stages of four of these species studies in the insectary of the Department
also described (Cavender and Goeden of Entomology, University of California,
1982, Goeden and Teerink 1997c; Head- Riverside, at 25 ± TC, and 14/10 (L/D)
rick and Goeden 1991, Knio et al. 1996a). photoperiod. Virgin male and female flies
This paper describes the life history of a obtained from emergence vials were paired
seventh species, T. jonesi, and its imma- (n = 16) in clear-plastic petri dishes pro-
ture stages. visioned with a flattened, water-moistened
pad of absorbant cotton spotted with honey
Materials and Methods
(Headrick and Goeden 1991, 1994) for ob-
This study began in 1991 and was based servations of their courtship and copulation
in large part on dissections ofselected sub- behavior.
samples of flower heads of Asteraceae in- Plant names used in this paper follow
fested by T. jonesi from among inany sam- Munz (1974), as updated by Hickman
ples collected annually throughout Califor- (1993) and Bremer (1994); tephritid names
nia in the manner described by Goeden and nomenclature follow Foote et al.
1985, 1992). One-liter samples ofexcised, (1993). Tenninology and telegraphic format
(
immature and mature flower heads from used to describe the iminature stages follow
known hosts potentially containing eggs, Knio et al. ( 1996a) and Goeden and Teerink
larvae, and puparia were transported in (1996a, b, c; 1997a, b, c) and our earlier
cold-chests in an air-conditioned vehicle to works cited therein. Means ± SE are used
the laboratory and stored under refrigera- throughout this paper. Voucher specimens
tion for subsequent dissection, photogra- of T. jonesi and its parasitoids reside in the
phy, description, and measurement. Four- research collections of RDG; preserved
teen eggs, 3 first-, 12 second-, and 7 third- specimens of eggs, larvae and puparia are
instar larvae, and 3 puparia dissected from stored in a separate collection of immature
flower heads were preserved in 70% EtOH Tephritidae maintained by JAT
for scanning electron microscopy (SEM).
Additional puparia were placed in sepa- Results and Discussion
rate, glass shell vials stoppered with ab-
Taxonomy
sorbant cotton and held in humidity cham-
bers at room teinperature for adult and par- Adult. Trupanea jonesi was described
asitoid emergence. Specimens for SEM by Curran (1932) (as Trupanea) from a fe-
were hydrated to distilled water in a de- male holotype and three female paratypes
creasing series of acidulated EtOH. They reared from Aster subspicatus Nees van
were osmicated for 24 h, dehydrated Esenbeck (as douglasi) at Corvallis, Ore-
through an increasing series of acidulated gon. Foote (1960), Foote and Blanc (1963),
EtOH and two, 1-h immersions in Hexa- and Foote et al. (1993) pictured the strik-
methlydisilazane (HMDS), mounted on ingly different, sexually dimorphic, wing
stubs, sputter-coated with a gold-palladium patterns of the female and male.
128 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
VOLUME NUMBER
100. 1 129
and placoid-type sensillum (Fig. 2F-2): cau- scribe thoracic and abdominal intersegmen-
dal segment circumscribed by minute acan- tal lines; gnathocephalon smooth, few ru-
thae (Fig. 2G-1), and stelex sensilla in a 2- gose pads laterad of anterior sensory lobe
dorsal, 4- ventral arrangement (Fig. 2G-2); (Fig. 3A-I); dorsal sensory organ a dome-
posterior spiracular plates, with three ovoid shaped papilla (Fig. 3A-2, B-1); subdorsal
mm
rimae, ca. 0.038 in length (Fig. 2G-3), sensillum laterad of dorsal sensory organ
and four interspiracular processes each with (Fig. 3B-2); anterior sensory organ bears all
mm
3-6 branches, longest measuring 0.013 four sensory organs (Fig. 3A-3, B-3); sto-
(Fig. 2G-4); intermediate sensory complex mal sense organ ventrolaterad of anterior
ventrad ofposterior spiracular plates among sensory lobe (Fig. 3B-4); mouth hooks bi-
the minute acanthae (Fig. 2G-5) consists of dentate (Fig. 3C-1); median oral lobe lat-
a medusoid sensillum (Fig. 2H-1), and a erally flattened, tapered anteriorly (Fig. 3C-
stelex sensillum (Fig. 2H-2). 2); prothorax circumscribed anteriorly by
Tnipaneajonesi is similar in general ap- minute acanthae, rugose pads and verruci-
pearance to other previously described spe- form sensilla; anterior thoracic spiracles
cies, i.e., Tnipanea californica (Headrick consist of 3-4 papillae (Fig. 3D); lateral
and Goeden 1991), T. bisetosa, T. nigricor- spiracular complexes were not seen; caudal
nis (Knio et al. 1996a), and T. signata segment circumscribed by minute acanthae
(Goeden and Teerink 1997c). Differences and stelex sensilla (Fig. 3E-1); posterior
among the Tnipanea species described to spiracular plates consist of three ovoid ri-
mm
date are found in the abdominal lateral spi- mae, ca 0.026 in length (Fig. 3E-2),
racular complex. This complex in T. cali- and four interspiracular processes, each
foniica includes a single verruciform sen- with 3-6 branches, longest measuring0.015
mm
sillum; in 7". nigricomis, two verruciform (Fig. 3E-3); intermediate sensory com-
sensilla; in T. jonesi, a placoid sensillum; in plex (Fig. 3E-4) consists of a stelex sensil-
T. signata. one verruciform sensillum and a lum (Fig. 3F-1) and a medusoid sensillum
placoid-type sensillum, and in T. bisetosa. (Fig. 3F-2).
two verruciform sensilla and a placoid-type The second instar differs from the third
sensillum (Headrick and Goeden 1991, instar in general habitus, being more cylin-
Knio et al. 1996a, Goeden and Teerink drical than barrel-shaped. The gnathoce-
1997c). Tnipaneajonesi is similar to T. sig- phalon has fewer rugose pads, none of
nata and T. nigricomis in having 3-6 which are serrated. The mouth hooks are
branches in the interspiracular processes bidentate, with the medial tooth being very
(Knio et al. 1996a, Goeden and Teerink reduced. The minute acanthae which cir-
1997c); whereas, T. californica and T bis- cumscribe the intersegmental lines are less
etosa possess 6-8 branches (Headrick and defined than in the third instar. Because of
Goeden 1991, Knio et al. 1996a). Phillips the wrinkled nature of the prepared speci-
(1946) described T jonesi with bidentate mens, the lateral spiracular complexes were
mouth hooks and anterior thoracic spiracles not observed. The ovoid rimae of the sec-
having 10 papillae; however, we show that ond instar are slightly smaller in size than
T. jonesi has tridentate mouth hooks and 3- those of the third instar.
4 papillae. Knio et al. (1996a) first reported First instar: White, cylindrical, tapering
the subdorsal sensillum in first instars of T slightly anteriorly, rounded posteriorly, 2-3
bisetosa and T. nigricomis; our report is the rows of minute acanthae circumscribe each
first to verify this sensillum in a third instar intersegmental Line; gnathocephalon smooth,
of Tnipanea. lacking rugose pads (Fig. 4B); dorsal sen-
Second instar: White, cylindrical, taper- sory organ a dome-shaped papilla (Fig. 4A-
ing slightly anteriorly, rounded posteriorly; 1, B-1); subdorsal sensillum laterad of dor-
weakly defined minute acanthae circum- sal sensory organ (Fig. 4A-2); anterior sen-
—
130 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
—Fig. 2. Third instarof—Trupaneajonesi: (A) hab—itus, anterior end to left;—(B) gnathocephalon. anteri—orview,
I serrated r—ugose pads, 2 verruciform sensilla, 3 dorsal—sensory organ. -1 anterior—sensory lobe, 5 mouth
hooks; (C—) 1 serrated rugose pad; an—terior sensory lobe, 2 —dorsal sensory organ, 3 s—ubdorsal sensory sen-
sillum. 4— terminal sensory organ, 3 pit sensory organ, 6 later—al sensory organ,—7 supralateral sensory
organ. 8 stomal sense organ; (D) gnathocephalon, ventral view, 1 mouth hooks, 2 median oral lobe, 3
——
VOLUME NUMBER
100, 1 131
mm
sory lobe bears all four sensory organs (Fig. in length; 1.26 ± 0.01 (range, 0.86-
mm
4A-3, B-2); stomal sense organs indistinct 1.65) in width.
(Fig. 4B-3); mouth hooks bidentate (Fig. The puparia of T. jonesi are similar in
4B-4); median oral lobe laterally flattened size to T. nigricomis, larger than T. cali-
(Fig. 4B-5); labial lobe attached to median fornica and T. imperfecta, and smaller than
oral lobe, bears two pore sensilla; minute T. bisetosa, T. conjuncta and T. signata
acanthae on ventral margin of prothorax; (Goeden 1987, 1988; Headrick and Goeden
anterior thoracic spiracles not present; lat- 1991; Knio et al. 1996a; Goeden and Teer-
eral spiracular complex not seen; caudal ink 1997c).
segment bears the posterior spiracular
plates, posterior spiracular plates with two Distribution and Hosts
mm
ovoid rimae, ca. 0.004 in length (Fig. The distribution of T. jonesi mapped by
4C-1), and four rudimentary interspiracular Foote et al. (1993) included the western
processes (Fig. 4C-2). third of the U.S. north of Mexico and Can-
The first instar differs from the previous ada, with this species recorded from several
two instars in lacking rugose pads on the locations each in Arizona, California, Col-
gnathocephalon and the prothorax. There orado, Idaho, Montana, Nevada, New Mex-
are also fewerminute acanthae circumscrib- ico, Oregon, Texas, Utah, Washington, and
ing each intersegmental line. The dorsal, Wyoming; from single locations in Iowa
subdorsal and anterior sensory lobe sensilla and Nebraska as well as from southern Brit-
are similar to the later instars, but the sto- ish Columbia.
mal sense organs are greatly reduced. Lat- Wasbauer (1972) and Goeden (1985,
eral spiracular complexes have been record- 1992) reported T. jonesi from eight tribes,
ed for first instars of Trupanea spp. (Knio 37 genera, and 86 species of Astereae in
et al. 1996a), but because the T.jonesi spec- North America. Eight new rearing records
imens were wrinkled, these structures were for T. jonesi are listed below in the manner
not observed. First instar T. jonesi differs of Goeden (1992), that along with taxo-
from T. bisetosa and T. nigricomis in hav- nomic changes in Hickman (1993) increase
ing greatly reduced interspiracular process- the reported host range to include eight
es (Knio et al. 1996a). tribes, 17 subtribes (Bremer 1994), 42 gen-
Piiparium: Most puparia of T. jonesi are era, and 104 species. All flies were reared
elongate-ellipsoidal (Fig. 5A), shiny black; from ca. 1-liter samples of mature flower
anterior end bears the invagination scar heads from California.
(Fig. 5B-1) and anterior thoracic spiracles New host genera. Chaetopappa, Oro-
(Fig. 5B-2); caudal segment bears the pos- chaenactis, Syntrichopappits
terior spiracular plates (Fig. 5C-1), a band New host records. Artemisia rothrockii
of minute acanthae (Fig. 5C-2), and the in- Gray; 4 $; Horseshoe Meadow at 2870-m
termediate sensory complex (Fig. 5C-3). elevation, Inyo Nat. Forest, Inyo Co.;
Fifteen (4%) of 341 puparia dissected from 14.ix.l993; Chaetopappa aurea (Nuttall)
flower heads (see below) were unpigmented Keck; 1 S, \ 9: Spillway Canyon at 1400
medially (Fig. 5A, 6G). The 341 puparia m, San Bernardino Nat. Forest (S. Section),
averaged 2.76 ± 0.01 (range, 1.82-3.44) Riverside Co.; 21.v.1996; Erigeron breweri
— —
labial l—obe sensilla; (E) gnathoc—ephalon, prothorax.—mesothorax, lateral view. 1 —minute acanthae, 2—rugose
pads, 3 verruciform sensilla, A stelex sensilla, ?—anterior tho—racic spiracle, 6 stelex sensillum, 7 verru-
ci—form sensillum; (F) —second abdominal se—gment. 1—spiracle, 2 placoid-type—sensillum; (G) caudal segment,
1 minute acanthae, 2 stelex sensill—uin, 3 rima,A interspi—racularprocess,5 intermediatesensorycomplex;
(H) intermediate sensory complex, 1 medusoid sensillum, 2 stelex sensillum.
132 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
— —
Fig. 3. Secon—d instar ot Tnipaiwu jtnicsi: lAi gnathocephalon. anterior v—iew, 1 rugose pads. 2 —dorsal
sensory organ. 3 —anterior sensory lobe; (B)—gnathocephalon. anterior view. 1 dorsal sensory organ.—2 sub-
dorsal se—nsillum. 3 anterior sensory lobe. A stomal sense organ; (C) gnathocepha—lon. ventral view. 1 —inoulh
ho—oks. 2 median oral lobe;—(D) anterior thoracic spiracles; (E) caudal segment. I stelex sensill—um. 2 rima,
3 inters—piracular process. 4 intermediate sensory complex; (F) intermediate sensory complex. 1 stelex sen-
sillum, 2 medusoid sensillum.
VOLUME 100, NUMBER 1 133
w
134 PROCEEDINGS OFTHE ENTOMOLOGICAL SOCIETY OF WASHINGTON
W
Gray; 2 d, 1 9; of Carson Pass at 2470 preblossom heads of A. alpigemis (Torrey
m along St. Hwy. 88, Eldorado Nat. Forest, and Gray) Gray, the long axes of single
Alpine Co.; 18.viii.l993; Orochaenactis eggs lay perpendicular to the receptacle in
thysanocarpha (Gray) Coville; 1 cj, 1 9; two heads (Fig. 6B), or at 15° from the per-
SE of Powell Meadow at 2440 m. Sequoia pendicular in the other two heads. The pas-
Nat. Forest (N Section), Tulare Co.; sage of the aculeus was marked by small
15.vii.l993; Senecio fremontii Torrey and round punctures in the phyllaries (Fig. 6C).
Gray; 1 9; 1 km S ofOsa Mountain at 2610 The diameters of the receptacles of 16 of
m. Sequoia Nat. Forest (N. Section), Tulare these heads containing eggs averaged 2.9 ±
Co.; 15.vii.l996; S. hydrophilus Nuttall; 1 0.2 (range, 1.6-4.0) mm, and 21 such heads
i; Pimentel Meadows at 2210 m along St. contained an average of 3 ± 0.4 (range, 1-
Hwy. 395, Mono Co.; 18.viii.l993; Syntri- 6) eggs oviposited singly or side by side in
chopappus fremontii Gray; 15 S, 18 9; N pairs by one or more females. An average
W
of Saddleback Butte at 927 m, Mojave of 2.4 ± 0.5 (range, 1-5) ovules were dam-
NW
Desert, Los Angeles Co.; 16.iii.l996; aged by an aculeus during oviposition in
Tetradymia canescens deCandolle; 1 cj, 1 seven of—these heads.
9; SW of Smith Mountain at 2440 m. Se- Larva. Upon eclosion, first instars tun-
quoia Nat. Forest (N Section), Tulare Co.; neled into and fed on the ovule and une-
14.vii.l993. longated floral tube of a single floret, then
The host record for Helenium hoopesii moved into an adjacent, more centrally lo-
Gray in Wasbauer ( 1972) was confirmed by cated floret. An average of 1.8 ± 0.3 (range,
us since publication of Goeden (1992). All 1-6) first instars were found feeding within
104 of the reported hosts of T. jonesi are 21 closed, preblossom heads from A. inte-
from California, and all but 15 ofthese rep- grifoliiis and A. alpigenus. The receptacles
resent our or RDG's rearing records, in- of these two Aster spp. averaged 3.9 ± 0.2
mm
cluding four from Wasbauer (1972) which (range, 1.4-5.7) in diameter with an
we have confirmed to date. Thus, as pre- average of 70 ± 3 (range, 48-89) ovules/
viously noted, T. jonesi retains its distinc- florets, of which an average of 4.6 ± 1.0
tion as having the broadest host range in (range, 1-17) ovules/florets, or 6% (range,
terms ofknown genera and species attacked 1-28%), were damaged. Receptacles within
of any native tephritid from California, and these 21 infested flower heads were not
from North America (Wasbauer 1972; Goe- scored (visibly abraided) by larval feeding.
den 1985, 1992; Foote et al. 1993). Again, Second instars fed mainly on ovules of
most hosts of T. jonesi in California belong preblossom flower heads or soft achenes of
to the Astereae, with good representation open heads, and usually at or near the cen-
also in the tribes Helenieae, Heliantheae, ters of these flower heads (Fig. 6D). A few
and Senecioneae (Munz 1974, Hickman second instars were found at the margins of
1993, Bremer 1994). Similarly, the sub- flower heads ofA. alpigenus and Helenium
tribes Asterinae, Chaenactidinae, Senecion- hoopesii Gray (Fig. 6E). Again, neithersev-
inae, and Solidagininae of Bremer (1994) en, closed, preblossom flower heads of A.
include the most host species. alpigenus nor six, open flower heads of
Chaenactis douglassi (Hooker) Hooker and
— Biology Amott, averaging 4.2 ± 0.1 (range, 3.4-
mm
Egg. In 17 closed, preblossom, imma- 4.7) in diameter had receptacles that
ture flower heads ofAster integrifoliiis Nut- were scored by larval feeding (see below).
tall, eggs were inserted pedicel-last through These 13 flowerheads contained an average
the phyllaries, and deposited either parallel of 1.5 ± 0.3 (range, 1-4) larvae that had
to the receptacle (n = 15, 88%; Fig. 6A), destroyed an average of 3.3 ± 0.9 (range,
or perpendicular to it in two heads. In four 1-10) ovules/soft achenes, or 7.3% (range.
.
VOLUME NUMBER
100. 1 135
2.5-14.3%) of an average total of47 ± 8.2 hosts averaged 4.4 ± 0.1 (range, 2.5-6.1)
mm
(range, 18-89) ovules/soft achenes in these in diameter and bore an average total
infested flower heads. of 80 ± 2 (25-119) soft achenes/florets, of
Third instars confined their feeding to which an average of 7.3 ± 0.5 (range, 2-
soft achenes or florets in the centers ofopen 40) soft achenes/florets or 16% (range, 1-
or postblossom heads, respectively (Fig. 15%) were damaged. These heads con-
6F). In 85 infested flower heads from 10 tained an average of 1.7 ± 0.1 (range, 1-
different host species averaging 3.8 ± 0.1 15) puparia. Most puparia of T.jonesi were
mm
(range, 1.9-7.8) in diameter and con- found in the centers of the heads, all had
taining an average of 1.4 ± 0.8 (range, 1- their anterior ends facing away from the re-
3) third instars (Fig. 6F), an average of 5.9 ceptacles, and their long axes were perpen-
± 0.5 (range 1-22) soft achenes/florets dicular to the receptacles (Fig. 6G, H). Tni-
were damaged, or 15% (range, 2.2-76%). paneajonesi generally infested only a small
Most third instars fed with their long axes proportion of the flower heads sampled and
oriented perpendicular to, and mouthparts damaged only a small proportion of the im-
directed toward the receptacles, within the mature achenes of the hosts Usted in Table 1
lower parts of the floral tubes and upper Receptacle scoring by T. jonesi larvae
parts of the soft achenes, well above the during feeding apparently was not obliga-
receptacles. The receptacles were scored in tory, as it was absent in all infested flower
only six (7%) of the 85 heads; i.e. in one heads of Aster breweri (Gray) Semple,
of two infested heads of Coreopsis califor- Chaenactis douglasii (Hooker) Hooker and
nica (Nuttal) H. K. Sharsmith; two of 31 Amott, Chaenactis xanthiana Gray, and
(6%) heads of A. integrifoliiis; one of two Layia glandiilosa; whereas, the receptacles
heads ofH. hoopseii (Fig. 6E); and three of of all 28 infested flower heads of Coreopsis
four heads of Chaenactis xantiana Gray. califarnica examined were scored (Fig.
Three of the six heads with scored recep- 6G). The receptacles also were scored in
tacles contained two or three larvae each, three of 77 (4%) infested flower heads of
which suggests a positive trend toward re- Arnica chamissonis Lessing (Fig. 6H);
ceptacle scoring at higher larval density and three of four (75%) infested flower heads
a greater propensity for scoring within ofAster alpigenus; eight of47 (17%) flow-
heads of certain hosts, for example, as re- er heads of Aster integrifolius: one of 29
ported among larvae ofParacontha gentilis (3%) infested flower heads of Chaenactis
Hering in flower heads of native Cirsium fremontii Gray; and nine (26%) of 35 in-
thistles (Headrick and Goeden 1990). (Re- fested flower heads ofEriophyUum lanatmn
ceptacle scoring also is analyzed in greater (Pursh) Forbes. Two ofthree (66%) infested
detail below within heads containing pu- flower heads each of Arnica chamissonis
paria.) Upon completing feeding, the larvae and Aster alpigeniis. six of eight (75%)
oriented with their anterior ends away from flower heads ofAster integrifolius. and sev-
the receptacles, retracted their mouthparts, en of eight (88%) with scored receptacles
and pupariated. contained more than one puparia, which
—
Pupa. Flower heads containing puparia again suggests a positive correlation of lar-
(Fig. 6G, H) reflected the greatest amount val densities and incidence of receptacle
of damage that the seed-feeding larvae of scoring (Headrick and Goeden 1990).
—
T. jonesi caused within heads of hosts sam- Adult. The duration of the larval and
pled. Accordingly, 434 flower heads of 10 pupal stages together approximated the du-
host species in six genera found to contain ration of flower head development. Adults
puparia were analyzed altogether, and by emerged from mature flower heads, and
host genus and species (Table 1). The re- were long-lived under insectary conditions,
ceptacles of infested flower heads of all 1 as eight males averaged 63 ± 6 (range, 42-