ZooKeys 382: 13225 (2014) A peer-revi iewed open-access journa I

doi: 10.3897/zookeys.382.6600 RESEARCH ARTICLE #ZooKey

WWwW.ZOO keys.o rg Launched to accelerate biodiversity research

A new species of Gadirtha Walker (Nolidae, Eligminae):
a proposed biological control agent of Chinese tallow
(Triadica sebifera (L.) Small) (Euphorbiaceae) in the
United States

Michael G. Pogue!"

I Systematic Entomology Laboratory, PSI, Agricultural Research Service, U.S. Department of Agriculture, clo
Smithsonian Institution, RO. Box 37012, NMNH, MRC-168, Washington, DC 20013-7012, USA

T Attp://zoobank.org/B16CC719-0398-4D 1 1-9658-8438E9127155

Corresponding author: Michael G. Pogue (michael.pogue@ars.usda.gov)

Academic editor: C. Schmidt | Received 12 November 2013 | Accepted 6 February 2014 | Published 19 February 2014
http://zoobank.org/80C D075 B-7AD6-4BF3-B729-5 1320F68B837

Citation: Pogue MG (2014) A new species of Gadirtha Walker (Nolidae, Eligminae): a proposed biological control agent
of Chinese tallow (Triadica sebifera (L.) Small) (Euphorbiaceae) in the United States. ZooKeys 382: 13-25. doi: 10.3897/
zookeys.382.6600

Abstract

Gadirtha fusca sp. n., is described from Guangxi Province, China. Gadirtha fusca differs in forewing color
and pattern, male and female genitalia, and in larval pattern from all other species of Gadirtha. Gadirtha
fusca has been evaluated as a potential biological control agent for Chinese tallow (Triadica sebifera (L.)
Small, Euphorbiaceae) in the southeastern United States. Adult, male and female genitalia, larva, and
pupa are described, illustrated, and compared with Gadirtha impingens Walker.

Keywords

China, Taxonomy, new species, biological control, larva, pupa

Introduction

The genus Gadirtha Walker was revised by Holloway (2003) and included three species;
the type species G. impingens Walker, G. pulchra Butler, and G. inexacta Walker. Gadir-
tha pulchra and G. impingens are the most widespread. Gadirtha pulchra ranges from the

Copyright Michael G. Pogue. This is an open access article distributed under the terms of the Creative Commons Attribution International License
(CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

14 Michael G. Pogue / ZooKeys 382: 13-25 (2014)

Indian Subregion, to the Ryukyu Islands in Japan, and Thailand, Singapore, New Guin-
ea, and Queensland, Australia; G. impingens ranges from northern India and south-
ern China to Queensland, the Bismarcks, and Solomons, (Holloway 2003) and from
Honshu, Shikoku, Kyushu, and Tsushima in Japan (http://www.jpmoth.org). Gadirtha
inexacta is found in northern India and Burma, and G. fusca in southern China.

A molecular phylogeny of Nolidae used eight genes to produce a stable phylogeny
that consisted of eight strongly supported subfamilies (Zahiri et al. 2013). Holloway
(2003) originally placed Gadirtha in the Collomeninae, but the results of Zahiri et al.
(2013) moved all of the Eurasian genera formerly associated with Collomeninae to
the subfamily Eligminae. Holloway (2011) preempted the placement of Gadirtha in
Eligminae based on characters outlined in Zahiri et al. (2013). Members of Eligminae
have an elongate and narrow forewing and in some genera the uncus is absent in the
male genitalia. Species of Gadirtha have an elongate and narrow wing and the uncus is
replaced by stiff, hairlike setae.

Gadirtha fusca is being considered as a potential biocontrol agent against Chinese
tallow (Triadica sebifera (L.) Small, Euphorbiaceae) in the southeastern United States and
formal description is critical to this process. Once G. fusca is introduced it will be the
largest Nolidae in North America and can easily be distinguished by its elongate forewing
with a truncate apex, dark gray forewing ground color with reduced pattern, and a dark
gray hind wing. These characters will also distinguish it from other Gadirtha species in
Asia. This paper describes the last instar, pupa, adult, and male and female genitalia.

Methods and materials

Images of adults and genitalia were taken with a digital camera, macro lenses, and a
pulsed xenon flash. Images were enhanced with Adobe Photoshop® CS4.

Genitalia dissections follow Pogue (2002), except the genitalia were mounted in
euparol. Vesica was inflated with 99% isopropyl alcohol and stained in Orcein.

Comparisons of forewing ground color and pattern, hind wing color, and male
and female genitalic structures were compared with all species of Gadirtha using Hol-
loway (2003). The male genitalia of G. fusca most closely resembled G. impingens, but
differences are illustrated by comparing Figures 5 and 6.

Material used in this study is deposited in the following institutions: The Natu-
ral History Museum, London (BMNH), Canadian National Collection, Agriculture
Canada, Ottawa, Canada (CNC), and National Museum of Natural History, Smithso-
nian Institution, Washington, DC (USNM).

Key to species of Gadirtha

1 Forewing with a distinct, thin, black postmedial line from costa slightly ex-
curved then abruptly angled to tornus; hind wing white with a narrow dark

A new species of Gadirtha Walker (Nolidae, Eligminae): a proposed biological control agent... 15

gray shading along outer margin, wing veins highlighted with dark gray (see
plate: Jyhem2 iia Plolloway( 2003) ) e acsbiadeBanracasscueeSeanaaeste. eet G. pulchra

= Forewing with postmedial line indistinct, consisting of only a few black scales;

hind wing white with broad gray marginal band or completely gray........... 2
2 Forewing dark gray; hind wing dark gray... eee eseeeeseereees G. fusca sp. n.
- Forewing pale gray to brownish gray; hind wing white basally with a broad
Gat At Meret al Sanaa. Motte h ater eheee et ok radon eursh Seats ail alt 3
3 Male genitalia with costal arm of valve slightly curved with a dorsal triangu-

late projection near apex (see fig. 502 in Holloway (2003))........ G. inexacta
-- Male genitalia with costal arm bent at a 90° angle (Fig. 5) ...... G. impingens

Descriptions

Gadirtha fusca Pogue, sp. n.
http://zoobank.org/9AB88C1D-C3DD-4113-8B75-94656AFDFAA8
http://species-id.net/wiki/Gadirtha_fusca

Figs 1-2, 5, 7, 9, 11-20

Type-locality. China, Guangxi Province, 4.4 km NW Yangshuo, 24.79833°N,
110.45067°E.

Type-specimen. Holotype male, Original label: “China, Guangxi Province, 4.4
km NW Yangshuo, 24.79833°N, 110.45067°E, 8 June 2012” “Reared from leaf 7’
sebifera 10-Sep.-2012 from IPRL colony” USNM ENT 00149216” “HOLOTYPE /
Gadirtha fusca | Pogue” [red printed label]. Deposited in USNM.

Paratypes. 3 males and 4 females same data as holotype; 2 male genitalia slides
USNM 136482, 136485; 2 female genitalia slides USNM 136483, 136484. 5 males and
5 females same data as holotype, from IPRL colony May 2013. USNM, BMNH, CNC.

Diagnosis. In the male genitalia G. fusca is most closely related to G. impingens
as they share the same 90° angle in the apex of the costa in the valve (Figs 5-6). The
aedeagus is abruptly bent medially in G. fusca (Fig. 7) and curved beyond the mid-
point in G. impingens (Fig. 8). In G. pulchra and G. inexacta the costal arm of the valve
is slightly bent, not curved at a 90° angle. The costal arm of the valve in G. inexacta
bears a dorsal triangulate projection near its apex (see fig. 502 in Holloway (2003))
and this projection is absent in G. pulchra see fig. 500 in Holloway (2003). In the
female genitalia the ostium bursae in G. fusca is membranous internally with a thin,
sclerotized outer margin shaped like an up-side-down conventional incandescent light
bulb (Fig. 9); compared to a heavily sclerotized ostium bursae that is strongly curved
ventrally (Fig. 10) in G. impingens. Gadirtha fusca cannot be confused with any of the
other three species of Gadirtha with its gray forewings, subdued pattern, and solid
dark gray hind wings (Figs 1-2). Forewing ground color is brown to brownish gray
in G. impingens with distinct black costal spots (Figs 3—4), contrasting with the dark
gray forewing and faint costal spots in G. fusca. Hind wing in G. fusca is dark gray and

16 Michael G. Pogue / ZooKeys 382: 13-25 (2014)

4

Figures |—4. Adults of Gadirtha species. | Gadirtha fusca sp. n., Holotype, male 2 Gadirtha fusca sp. n.,
female 3 Gadirtha impingens Walker, male 4 Gadirtha impingens Walker, female.

white basally and dark brown distally in G. impingens. Only G. fusca and G. impingens
are distributed in China.

Larvae have a pale green to yellow-green ground color with elongate black and
white setae. Pattern differences are distinct between species. Gadirtha fusca has a dis-
tinct, wide black dorsal stripe with large, ovate, black spots on Al, A2, and A8 (Figs
13-14). In G. impingens, the dorsal black stripe can be absent or if present, a thin line
on each segment that is not contiguous; black ovate spots on Al and A2 are smaller
than in G. fusca and a small black round spot on A8 (http://jpmoth.org/Nolidae/
Eligminae/Gadirtha_impingens.html). In G. pulchra the black spots are ringed with
blue on T2—A4, with the largest spots on T3 and A1 (colour plate 12, fig. F in Murphy
1990).

Description. Adult (Figs 1-4): Male. Head — labial palp extends well above head,
apical segment with slightly bulbous apex, dorsal surface adjacent to eye black, becom-
ing pale gray with apical third dark gray, apex white, ventral surface white; frons and
vertex gray; antenna ciliate and bare ventrally, white scales dorsally. Zhorax — patagium
grayish brown, a curved black line from middle to posterior margin; tegulum with pale
gray scales tipped white, a few tipped black, black band of scales just proximal to apex;
scales of protibia narrow, gray tipped white, greatly expanded laterally and ventrally
almost to last tarsal segment, two vertical black spots medially that continue onto tarsal
segments 1—4, tarsi concolorous with protibia with laterally expanded scales; meso-
thoracic tibia concolorous with protibia, scales expanded laterally less than in protibia

A new species of Gadirtha Walker (Nolidae, Eligminae): a proposed biological control agent... 17

Figures 5-6. Male genitalia of Gadirtha species; un uncus ca costal arm of valve. 5 Gadirtha fusca sp. n.
6 Gadirtha impingens Walker.

and expanded ventrally to basitarsus, tarsi black dorsally, a few brown scales laterally,
white ventrally; metathoracic tibia cream colored, tarsi cream colored with black basal
bands on segments 2—4. Forewing length 18.5—22.4 mm; ground color brownish gray;
varying amounts of indistinct rufous areas distributed over forewing; costa with rectan-
gulate dark gray basal spot and a fainter dark gray triangulate spot proximal to apex;
antemedial line black, very thin, angulate from R vein to anal vein; medial line absent;
orbicular spot obscure, a round area consisting of a few pale scales bordered either dis-

18 Michael G. Pogue / ZooKeys 382: 13-25 (2014)

Figures 7-8. Aedeagi of Gadirtha species. 7 Gadirtha fusca sp. n. 8 Gadirtha impingens Walker.

tally or proximally by a crescent-shaped band of dark gray scales; reniform spot round
with a slightly produced apex along distal margin, thinly outlined in black, medially a
vertical bar shape to ovate spot, rufous to dark gray; postmedial line very thin, black,
indistinct, irregular in shape, excurved; black distal line at apex of vein CuA2; termi-
nal line a series of black dashes between wing veins; outer margin angled at tornus to
posterior margin; posterior margin a narrow white line with closely spaced black verti-
cal lines, this line can be variable in extent and intensity. Hind wing dark gray. Abdo-
men — Dark gray. Genitalia (Figs 5, 7) — Uncus slightly sclerotized with stiff, hair-like
setae at apex; subscaphium well developed, a wide U-shape with bottom of U broad;
valve bifurcate, costa curved ventrally to just beyond apex of valve, cucullus lightly
sclerotized; corona absent; saccus a broad U-shape; aedeagus short, angulate medially,
vesica an elongate sac, slightly bulbous apically. Female. Head — Antenna not ciliate.
Thorax — Similar to male except forewing length 20.9-23.1 mm; ground color pale
brownish gray; antemedial line irregular and minutely wavy extending from costa al-
most to posterior margin; orbicular spot more pronounced than in male, a central area
of pale scales surrounded by a dark gray crescent-shaped border usually disto-ventrally;
a subapical elongate triangular spot on costa with two short black dashes near apex of
spot. Genitalia (Fig. 9) — Papillae anales rectangulate, setose, slightly sclerotized; os-

A new species of Gadirtha Walker (Nolidae, Eligminae): a proposed biological control agent... 19

Figures 9-10. Female genitalia of Gadirtha species. 9 Gadirtha fusca sp. n. 10 Gadirtha impingens Walker.

tium bursae bulb-shaped, narrow at exit of eighth tergite, then bulbous basally; ductus
bursae short, sclerotized, and quadrate at exit from ostium bursae, remainder elongate,
membranous slightly widens to elongate corpus bursae; signum an elongate, crenulate
ribbon almost length of corpus bursae.

20 Michael G. Pogue / ZooKeys 382: 13-25 (2014)

Figures | 1-12. Larva of Gadirtha fusca sp. n. (preserved in alcohol). 11 dorsal 12 ventral.

Larva (Figs 11-14): Length: 28.0-33.5 mm (z = 6). Coloration and pattern.
Head — Yellow. Thorax —'T1 with medial rectangular black spots surrounding D1, D1
pinnacula yellow, irregular shaped black spot between XD2 and SD1, black spinules
distal to all black spots; T2 and T3 with patch of black spinules between D1s, between
D2 and SD2, distal to L group, and dorsal to SV group. Abdomen — yellow; dorsal line
distinct black, ovate spots on Al, A2, and A8, remainder of segments with small round
spots, spiculate; subdorsal, lateral, and spiracular lines pale green, spiculate; A10 with
D1s surrounded by large, irregular shaped black spot, pinnacula yellow. Morphol-
ogy. Head — Front flat; hypognathous; cutting edge of mandible with 3 shallow teeth,
dorso-medial internal surface with large molar-like tooth, round and peg-shaped; epi-
cranial suture elongate; epicranial notch moderately emarginated dorsally; Fl, AF1
equal in length, AF2 longer; C1 shorter than C2; P1 dorsal to AF2, P2 inline with and
dorsal to P1, shorter than P1; L1 fine, shorter than A3; S2 distal to stemma 1, shorter
than S1; S1 ventral to stemma 3; stemmata 1-3 large and equal in width, larger than
stemmata 4—6; spinneret cylindrical, equal in length to labial palp. Thorax — Spiculate;
verrucae absent; [1 with D1, D2, XD1, and XD2 elongate, black; SD1 and SD2 on

A new species of Gadirtha Walker (Nolidae, Eligminae): a proposed biological control agent... 21

Figures 13-14. Larva of Gadirtha fusca sp. n. 13 on Chinese tallow 14 on Chinese tallow.

prothoracic shield, pale, less than half length of other setae; single prespiracular seta;
SV1 and SV2 on same pinnacula; ventral projection present. T2 and T3 with D1, D2,
SD1, and SD2 elongate, black on separate, conical pinnacula; L1 and L2 on same pin-

nacula, black (L1 pale on T3), L2 longest, L3 short, pale, and hairlike; SV1 and SV2

22 Michael G. Pogue / ZooKeys 382: 13-25 (2014)

Pn
Mx
Lp
PF Msn
P|
Msl Mtn
A A1
A2
Fw A3
Mtl ms
A5 Ad
A6 A6
%4 Af?
i A8
A8 AY

17

Figures 15-17. Male pupa of Gadirtha fusca sp. n. (preserved in alcohol). 15 dorsal 16 ventral 17 clo-
seup of A8—A10 (A antenna; As anal suture; Fw forewing; Gs genital suture; Lp Labial palp; Msl meso-
thoracic leg; Msn mesonotum; Mtl metathoracic leg; Mtn metanotum; Mx maxillae; Pf prothoracic

femur; Pl prothoracic leg; Pn pronotum).

elongate, white, on same pinnacula. Abdomen — Spiculate; Al with D1, D2, SD1, and
L1, elongate, black; D2 on very large conical pinnacula; SD2 white, hairlike, directly
caudal to spiracle; L1 brown, posterior to spiracle, L2 and L3 white on separate pin-

naculae; SV1 and SV2 present. A2 with D1, D2, SD1, L1, elongate, black; D2 on

A new species of Gadirtha Walker (Nolidae, Eligminae): a proposed biological control agent... 23

Gs

As

20

Figures 18-20. Female pupa of Gadirtha fusca sp. n. (preserved in alcohol). 18 dorsal 19 ventral 20 clo-
seup of A8—A10 (A antenna; As anal suture; Fw forewing; Gs genital suture; Lp Labial palp; Msl meso-
thoracic leg; Msn mesonotum; Mtl metathoracic leg; Mtn metanotum; Mx maxillae; Pf prothoracic

femur; PI prothoracic leg; Pn pronotum).

conical pinnacula, but smaller than on AJ; rest of setae as in Al except L1 posterior
and ventral to spiracle. A3-A6 with D1, D2, and SD1 elongate, black; SD2 white,
hairlike; L2 and L3 white on separate pinnaculae; 3 SV setae, white; crochets uniordi-
nal mesoseries. A7—A8 with D1 and D2 black, L1 white on A7 and black on A8, elon-
gate; SD2 caudal to spiracle, white, hairlike; on SV seta. A9 with D1, D2, SD1, and
L1, elongate, black; L and SV group absent; A9 appears to fuse with A8 ventrally. A10

24 Michael G. Pogue / ZooKeys 382: 13-25 (2014)

with D1 and SD1 brown, elongate; SD2 pale brown, elongate; D2 white, elongate;
SV1, L2 and L3 brown, elongate; 4 SV setae white; crochets uniordinal mesoseries.

Pupa (Figs 15-20): Length: 18.8-19.0 mm in male (7 = 3) (Figs 15-17), 18.8-
19.2 mm in female (7 = 3) (Figs 18-20). Obtect; adecticous; smooth, dark brown; la-
bial palpus (Lp) extends from clypeus to approximately 0.7 x length of maxillae (Mx);
prothoracic leg (Pl) approximately 1.16 x length of maxillae; prothoracic femora (Pf)
present, narrow, shorter than maxillae; maxillae short, approximately half the length
from clypeus to forewing apex; mesothoracic leg (Msl) approximately 0.8 x length
from clypeus to forewing apex; antenna (A) shorter than mesothoracic leg; metathorac-
ic leg (Mtl) visible between mesothoracic leg and apex of forewing; segments A8—A10
separate in male A9—A10 fused in female; genital suture on A9 in male set between two
bumps and on A8 in female; anal suture on A10; cremaster absent.

Etymology. ‘The specific epithet refers to the dark grayish brown ground color of
the forewing.

Biology. Gadirtha fusca overwinter as eggs on leaves and branches of Chinese tal-
low and hatch in May. Larvae feed on leaves and complete six instars in 15 days and
can cause extensive defoliation, especially during the last three instars. There can be
4—5 generations per year in Hubei Province (Wang et al. 2012).

Distribution. East central and southeastern China.

Discussion. It is curious why G. fusca was misidentified in the biocontrol literature
as G. inexacta (Wang et al. 2012). In reviewing Holloway (2003), G. inexacta does not
occur in China and the life history is unknown. The more obvious misidentification
would be with G. impingens, which does occur in China, larvae are known to feed on
species of Euphorbiaceae, and morphology of the male genitalia are similar.

Acknowledgments

I thank Gary D. Ouellette, USDA, Systematic Entomology Lab for taking all of the
images. Gregory S. Wheeler, Invasive Plant Research Laboratory, USDA, Ft. Lauderd-
ale, FL supplied all of the specimens and Figs 13—14. Two anonymous reviewers added
excellent ideas to this paper.

Mention of trade names or commercial products in this publication is solely for
the purpose of providing specific information and does not imply recommendation or
endorsement by the USDA; USDA is an equal opportunity provider and employer.

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