Table Of ContentPROC. ENTOMOL. SOC. WASH.
93(1), 1991, pp. 16-44
SYSTEMATICS, MORPHOLOGY, BIOLOGY, AND HOST
SPECIFICITY OF NEUROSTROTA GUNNIELLA (BUSCK)
(LEPIDOPTERA: GRACILLARIIDAE), AN AGENT FOR THE
BIOLOGICAL CONTROL OF MIMOSA PIGRA L.
Donald R. Davis, Richard C. Kassulke,
Ken L. S. Harley, and John D. Gillett
(DRD) Department ofEntomology, National Museum ofNatural History, Smithsonian
Institution, Washington, D.C. 20560; (RCK & KLSH) CSIRO Division ofEntomology,
Long Pocket Laboratories, Private Bag No. 3, Indooroopilly, Australia 4068; (JDG) De-
partment ofPrimary Industries and Energy, PC Box 858, Canberra, Australia 2601.
Abstract. —The systematics and morphology ofthe gracillariid moth, Neurostrota gun-
niella (Busck, 1906), from Mexico are reviewed. The biology and host specificity ofthis
moth were studied in quarantine facilities in Brisbane, Australia. Eggs were usually laid
singly on the ventral surface of mature leaves of Mimosa pigra L. The first two larval
instars were sap-feeding miners in the leaf pinnules. Instars three to eight were tissue-
feeding stem borers. Pupation occurred outside the stem within a silken cocoon festooned
with frothy globules excreted by the larva.
One hundred species of plants, either closely related to M. pigra or of economic or
environmental importance, were tested in host specificity studies as part ofan assessment
ofthe suitability ofA^. gunniella as a biological control agent forM. pigra. The only plants
which supported development ofN. gunniella were the two introduced weeds, M. pigra
and M. pudica, and four Australian Neptunia species. Larval mortality was high on the
Neptunia species. These studies showed that A^. gunniella would not cause damage to any
plant other than the target weed, M. pigra in Australia. A^. gunniella was first released
near Darwin, Australia in February, 1989.
Key Words: Lepidoptera biology, Gracillariidae, Neurostrota, Mimosapigra, biological
control, host specificity
Mimosa, Mimosa pigra L. (Legumino- laide River, with major infestations on the
sae), is native to tropical America (Burkart Finniss, Mary, and East Alligator Rivers
1948) where it usually occurs as small (Pitt and Miller 1989, Miller 1982). M. ;?/-
clumpsofmulti-stemmedplantsgrowingin gra is a designated Class "A" noxious weed
seasonally flooded habitats (Fig. 1). It prob- in the Northern Territory (Noxious Weeds
ably entered the Northern Territory of Ordinance 1962), is a serious weed in Thai-
Australia during the 20 years prior to 1891 land (Napompeth 1982) and is spreading in
(Miller&Lonsdale 1987), underwentapop- Burma, Laos, Kampuchea, Vietnam, In-
ulationexplosion inthelate 1970'sandnow donesiaand Malaysia(Napompeth, B., pers.
infests45,000 haofwetlands(Lonsdale and comm.). In the Northern Territory it pre-
Segura 1987). Dense to scattered thickets of vents access for irrigation and stock water-
M. pigra cover the floodplains ofthe Ade- ing, makes livestock musteringdifficult and
VOLUME NUMBER
93, 17
interferes with the use ofwatercourses for 41, 68. McDunnough, 1939: 97. Vari,
recreation (Miller et al. 1981). On flood 1961: 41. Davis, 1983: 9; 1984: 26.
plains it out-competes other plants and se- Neurostrata [sic] gunniella (Busck) Ely,
riously reduces dry season grazing forcattle 1918:41. Busck, 1934: 179.
and buffaloes. There and in Southeast Asia —
itoccursashuge, impenetrable, nearmono- 4.4Admumlt;(9F,ig3..22)-.4.6Fomrme.winSgmallelngmtho:th3, w3i.t3h-
specific thickets. dark coppery brown forewing possessing a
Two other Mimosa species, M. invisa
single, oblique, cream white stria at distal
Mart, and M. pudica L. have been intro- third of costa and hind margin bordered
duced into and become weeds in Australia with cream. Male valva rhombiform, sim-
(Kleinschmidt and Johnson 1977). M. in- ple; seventh abdominal segment with a sin-
visa is confined to Queensland and M. pu- gle pair ofelongate hair pencils and a more
dica is widespread throughout Queensland, basal tuft ofshort, spatulate sex scales. Fe-
northern New South Wales and the North- male bursa with a pair ofdiamond shaped
em
Territory.
signa.
A program for biological control of M. Head (Fig. 3): Vestiture smooth, scales
pigra in Australia was initiated by CSIRO curving down over frons; vertex cream to
and the Northern Territory Department of palebuff"at middle, becomingdarkerbrown
Primary IndustryandFisheries in 1979 and laterally; a patch ofbrownish fuscous scales
extended to Thailand through a program of at anterior rim ofeye below antenna; lower
the Australian Centre for International Ag- fronsmostlysilverywhite. Antennaca. 1.2x
riculturalResearch (ACIAR) in 1983. In in- lengthofforewing,coveredwithdarkbrown
vestigations in Mexico, adults of a gracil- scales dorsally and dull white ventrally.
lariid moth Neurostrota gunniella (Busck) Ocellus absent. Interocular index ca. 1.1.
frequently emerged from tips of M. pigra Mandible absent. Maxillary palpus mod-
and occasionally from tips of another le- erately long, four segmented, silvery white
gume native to Mexico, Neptuniaplena (L.) dorsally, grayish brown ventrally. Haustel-
Benth. Following preliminary tests in Mex- lum elongate, over 2x length oflabial pal-
ico for specificity to M. pigra, N. gunniella pus, coiled in repose. Labial palpus slender,
was imported into Australia for detailed elongate, over 2x vertical diameter ofeye,
evaluation in quarantine. curveddorsally; vestiture silverywhitedor-
This paper gives details ofstudies on the sally, grayish brown ventrally and laterally.
systematicsandmorphologyofA^. gunniella Thorax: Pronotum dark coppery brown
conductedatthe Smithsonian Institution as with a broad cream to pale buff" median
well as studies ofits biology and host spec- stripe; venter dark brown laterally, silvery
ificity carried out by the Division ofEnto- white over coxa. Wing venation as shown
mology, CSIRO, Australia. in Fig. 4. Female frenulumconsistingoftwo
bristles(Figs. 9-11), maleofonebristle, with
Systematics and Morphology basal fusion ofca. 5-6 setae (Figs. 12-14).
Both sexes with a secondary pseudofrenu-
Neurostrota gunniella (Busck)
lum arisingneartermination ofSc and con-
Gracilaria [sic] (Dialectica)gunniella Busck, sisting ofusually 3-4 piliform scales tightly
1906: 731. overlapping (Figs. 9, 15-18). Pseudofrenu-
Acrocercops gunniella (Busck) Meyrick, lum coupling with a row ofstiff', specialized
1912a: 16, 1912b: 44. Barnes and scaleslocatedalongthe ventralhind margin
McDunnough, 1917: 188. in the anal area of the forewing (Figs. 19,
Neurostrotagunniella(Busck)Ely, 1918:38, 20). Forewing mostly dark coppery brown
PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OFWASHINGTON
^^.
Figs. 1,2. 1, AdenseconcentrationofMimosapigranearAcapulco, Mexico. 2, Neurostrotagunniella. adult
s. forewinglength 4.2 mm.
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93, 1
Figs. 3-8. Neuwstrotagunniella. 3, Head, frontal view(0.25 mm). 4, Wingvenation, pf= pseudofrenulum.
5, Male genitalia, ventralview(0.25 mm). 6, Aedoeagus. 7, Femalegenitalia, lateral view (0.5 mm). 8, Ventral
view. (Scale lengths in parentheses.)
20 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OFWASHINGTON
with a single, cream-white stria extending maximum body width 1 mm; maximum
obHquely from distal third of costa about head width 0.54 mm; body color instars 1-
halfthe distance to tornus; a single, narrow, 7 cream, instar 8 dark blue-green, later re-
silver fascia transversing subapex; fringe verting to cream.
with a pair of dark brown striae curving
Sap-feeding Instars
around apex; hind margin bordered with
cream to tornus; fringe along hind margin Head:Greatlydepressed,triangular(Figs,
uniformly dark gray. Hindwing uniformly 32, 39). Most setae lost or reduced; dorsal
dark gray. Legs dark brownish fuscous with cranium with only two small pairs ofsetae
apex of tibia and most of tarsal segments preserved, P2 near basal lateral margin and
banded with cream; tarsi ofhindleg mostly LI above median (third) stemma. Labrum
dull white to pale buff. (Fig. 33) reduced, 0.64 the width of labial
Abdomen: Dark brownish fuscous dor- lobe, deeply clefted about 0.25 its length;
sally, mostly cream to white ventrally, with only one pair ofsetae preserved; venter of
5 slender, dark fuscous, oblique bands lat- labrum with dense concentration of short
erally across segments A2-6. Male with a epipharyngeal spines (Fig. 37). Mandibles
single pair of elongate hair pencils and a large, greatly flattened, with three primary
more basal tuft ofshort, spatulate sex scales cusps dorsally; innermost cusp broad with
lateral on A7, A7 greatly reduced. Tergite 8 serratedmargin; outermostcuspwithador-
enlarged, well defined, hoodlike, extending salgroove anda fourth, shortercusp arising
caudad oflateral sex scaling on A7. ventrad. Labial lobe (Figs. 34, 35) with an-
Malegenitalia (Figs. 5, 6): Uncus absent. terior margin slightly depressed at middle;
Vinculum, triangular with broad, lateral anterior margin and dorsal surface densely
projections dorsad to base ofvalva. Valva covered with short hypophyrangeal spines
rhombiform, with outer margin relatively (Fig. 38) similar to epipharynx; spinneret
straight and oblique. Aedoeagus relatively vestigial,reducedtoaminute, flushedopen-
simple, lightly sclerotized, equalling length ing ca. 0.86 Mm in diameter. Ventral cra-
of valva; comuti absent; phallobase 1.5 x nium with only a single pair of substem-
length ofaedoeagus. matalsetae(SS3?). Maxillaryandlabialpalpi
Femalegenitalia{Figs. 7, 8): Anteriorand absent. Antenna reduced, with three rela-
posterior apophyses equally developed, tively stout sensilla basiconica and three
short. Ductus bursae shorter than length of shorter, moreslendersensilla(Fig. 36). Five
corpus bursae; seminal duct arising midway pairs of stemmata present in an irregular
along ductus. Corpus bursae well devel- lateral row; an anterior row ofthree contig-
oped, ovoid, with a pair of roughly dia- uous stemmata followedby two morewide-
mond-shaped signa. ly spaced stemmata posteriorly.
—
Egg (Figs. 27-31). Elongate-ovoid, with Body:Setaeextremelyreduced. Legs, pro-
a minutely dimpled chorion; average length legs, and crochets absent.
0.357 mm, width 0.164 mm (n = 20). Mi-
Tissue-feeding Instars
cropylewith 3-6ovalringsclusteredaround
a minute central depression. Head:Approximately round (Figs. 40, 51)
Larva (Figs. 32-60, 63-70).-Hyper- with full complement of mouthparts, dark
metamorphic; first two instars with highly reddish brown. Frons (Fig. 64) moderately
modified, depressed body forsap-feeding in long, about 0.66 the distance to epicranial
leaf pinnules; maximum length, 1.2 mm. notch. Ecdysial line terminating at epicra-
Remaining six instars oftypical caterpillar nial notch. Chaetotaxy relatively complete;
form with cylindrical body, boring in stems all three MD setae present; AF2 absent; P2
of host. Length of largest larva 8.0 mm; reduced; LI arisingimmediatelycaudadand
VOLUME NUMBER
93, 1 21
Figs. 9-14. Neurostrotagunniella, wing structure. 9, Hindwing, female, showing basal frenulum and more
distal pseudofrenulum (270 nm). 10, Base offemale frenulum (23.1 ^m). 11, Surfacedetail offemale frenulum
(1.5 Mm)- 12, Base ofmale frenulum (10 Mm). 13, Surface ofmale frenulum (3 Mm). 14, Detail ofFig. 13 (1.5
Mm). (Scale lengthsin parentheses; bar scale forall photographs = Fig. 9.)
22 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OF WASHINGTON
A'^O^.
-W'/*
(P/\VMir
Figs. 15-20. Neurostrota gimniella. wing structure. 15, Male pseudofrenulum (120 mhi). 16, Base ofpseu-
dofrenulum (17.6 ^lm). 17, Overlappingscales ofpseudofrenulum(6 ^m). 18, Surfacedetailofpseudofrenulum
showmgoverlappingscutes(1.5 ^m). 19, Subanal retinaculum (SR)ofventral forewing(100 tim). 20, Detail of
scale (a) ofFig. 19 (2 ^m). (Scale lengths in parentheses; bar scale forall photographs = Fig. 15.)
VOLUME NUMBER
93, 1 23
Figs. 21-26. Neurostrota gunniella, life history. 21, Leafmines ofsap-feeding larva on Mimosa pigra. 22,
Frass ejected from stem burrow. 23, Larva inside tunnel within stem ofM. pigra. 24, Moth larva killed by
parasitic tachinid larva, Elfia n. sp. 25, Pupa inside cocoon spun on leaflets ofM. pigra. 26, Cocoon spun on
stem ofM. pigra, Note frothy bubbles excreted by larva.
24 PROCEEDINGS OFTHE ENTOMOLOGICALSOCIETY OFWASHINGTON
Figs. 27-32. Neurostrotagunniclla. 27, Egg (120 ^m). 28, Surface ofegg chorion (23.1 ^lm). 29, Micropyle
end (67 ^m). 30, Detail ofmicropyle (15 ^ni). 31, Detail ofmicropyle (17.6 ^m). 32, Sap-feedinglarva, dorsal
viewofhead (60 ^m). (Scale lengths in parentheses; bar scale forall photographs = Fig. 27.)
VOLUME 93, NUMBER 25
Figs. 33-38. Neurostrota gunniella, sap-feeding larva. 33, Labrum and mandibles, dorsal view (21.4 ^m).
34, Ventral viewofhead (50 nm). 35, Labium and antennae, ventral view (30 nm). 36, Antenna, ventral view
(7.5 ^m)- 37, Anterior view ofmouthparts (27 ^m). 38, Labium hypopharynx, ventral view; note aperture of
vestigial spinneret (4.3 nm). (Scale lengths in parentheses; bar scale forall photographs = Fig. 33.)
