Journal of Threatened
Taxa | www.threatenedtaxa.org | 26 April 2018 | 10(5): 11659–11664
The
first report of two thread-legged assassin bugs (Hemiptera:
Reduviidae: Emesinae) from
India
Balasaheb V. Sarode 1,
Swapnil S. Boyane 2
& Hemant V. Ghate 3
1,2,3 Post-Graduate Research Centre, Department of Zoology,
Modern College of Arts, Science and Commerce, Shivajinagar,
Pune 411 005, Maharashtra, India.
1 balasahebs78@gmail.com,
2 boyane.swapnil@gmail.com, 3 hemantghate@gmail.com
(corresponding author)
Abstract: Two Emesinae bugs, namely Stenolemus crassirostris
Stl, 1871, and Gardena brevicollis
Stl, 1871, are being reported for the first time
from India. Both are widespread
species but have never been recorded from India.
Keywords: Emesinae, Gardena, India, Reduviidae,
Stenolemus, thread-legged bugs.
doi: http://doi.org/10.11609/jott.3971.10.5.11659-11664
| ZooBank:
urn:lsid:zoobank.org:pub:3B78E104-EA76-4207-9223-6641D64F17B7
Editor: M. Malipatil, La Trobe
University, Bundoora,
Australia. Date
of publication: 26 April 2018 (online & print)
Manuscript
details: Ms # 3971 | Received 23 December 2017 | Final received 28
March 2018 | Finally accepted 04 April 2018
Citation: Sarode. B.V., S.S. Boyane & H.V. Ghate (2018). The first report of two thread-legged assassin bugs (Hemiptera: Reduviidae: Emesinae) from India. Journal of Threatened Taxa 10(5): 11659–11664; http://doi.org/10.11609/jott.3971.10.5.11659-11664
Copyright: Š Sarode et al. 2018. Creative Commons Attribution 4.0
International License. JoTT allows
unrestricted use of this article in any medium, reproduction and distribution
by providing adequate credit to the authors and the source of publication.
Funding: None.
Competing interests: The
authors declare no competing interests.
Acknowledgements: We
sincerely thank Dvid Rdei
(Nankai University, China) for his generous help with
literature, for answering numerous queries and for continuous support. Work on these interesting bugs would not
have become possible without his constant help. We also thank Dr. Tadashi Ishikawa
(Agriculture University, Tokyo) for his help. We thank Mr. Pratik Pansare
for collection of the male bug from Daund. Finally, we are grateful to the
authorities of Modern College for facilities and encouragement.
While surveying Heteroptera from 2016–2017, two assassin bugs of the
subfamily Emesinae were recently collected in Sharadwadi, Shirur Taluka, Pune District (Maharashtra
State). Of these two species, one
7mm long, hairy bug was identified as Stenolemus
crassirostris Stl,
1871 (Image 1A) while the other slender, 13mm long, bug was identified as Gardena
fasciata Distant, 1909 (now junior synonym of
Gardena brevicollis Stl,
1871) (Image 1B). Both these bugs
were identified using Distant (1904, 1910) and were confirmed using keys by Wygodzinsky (1966) as well.
Since none of these
two bugs are previously known to be in Indian territory,
this becomes the first record of these two species. The only published checklist of Reduviidae for India by Ambrose (2006) does not include
these species. Stl
originally described these species from the Philippines (Stl
1871) and are also known from Ceylon (now Sri Lanka), as mentioned by Distant,
cited above. Since useful
descriptions of both these species are available, we are only providing many
photographs of diagnostic characters with brief comments. We agree with Ang
et al. (2013) who stated that Ō (taxonomic)
descriptions should become more data-rich by presenting a large amount of
images and illustrations to cover as much morphology as possibleĶ.
Original
descriptions for both the species, as given by Stl
(1871), were checked. Detailed generic characters as well as
important diagnostic characters of each species have been given by various
workers (Distant 1904, 1909, 1910; Wygodzinsky 1956,
1966; Ishikawa 2005, Rdei & Tsai 2010), along
with line drawings, and so those are not given again. For various synonyms of Gardena brevicollis see Wygodzinsky
(1966) and Maldonado-Capriles (1990); Stenolemus crassirostris
has no synonym.
Materials and
Methods
Material studied:
One male Stenolemus crassirostris
(coll. B. Sarode 03.vi.2017),
found in an old, unused house with many spider webs and subsequently one female
was collected in a grass patch (coll. B. Sarode
12.xi.2017).
One male Gardena
brevicollis was collected when it was attracted
to light (coll. B. Sarode, 27.vi.2017); while one male was found dead in a spider web in Daund, Pune (coll. P. Pansare,
25.xi.2017).
The collected bugs
were preserved in 70% alcohol and dried for observation using standard
entomological methods. Properly
mounted insects were studied and photographed under Leica SMZ6 stereozoom with attached Cannon PowerShot
S50. Several images were taken at
different focus and stacked to get final image using Combine ZM freeware. The
images were processed and cleaned using Photoshop CS5. For preparation of male genitalia the
whole insect was briefly warmed in 10% KOH for 15–20 minutes and the pygophore was detached using fine forceps. The dissected insects were subsequently
treated with dilute acetic acid and washed in 70% alcohol before dry mounting
again. The dried specimens are maintained at the Department of Zoology, Modern
College. Detached pygophore was boiled in 10% KOH for 2 minutes, cooled and
boiled again for 2–3 minutes in fresh 10% KOH. This pygophore
was then stored overnight in 5% KOH before further dissection.
During dissection parameres and proctiger were
first removed and then the phallus was carefully removed. The phallus was further cleared from the
muscles using fine forceps, stained briefly in dilute Methylene Blue and
Eosin. In case of Gardena,
the endosoma was also everted. Permanent slides of phallus and parameres were prepared by standard methods. For phallus
and parameres the photographs were prepared on
microscope using an attachment for camera.
Genus: Stenolemus
Signoret, 1857
Stenolemus crassirostris Stl, 1871
Genus Stenolemus
is a species rich genus spread over all major zoogeographical areas and can be
diagnosed on the basis of characters like: pedunculate
pronotum, with distinct subglobular
anterior lobe, narrow peduncle and posterior, usually bell shaped, lobe
possessing a pair of discal projections and lateral carinae; incrassate labial segments; scuteller
and metanotal spines; relatively broad forewings that
pass beyond abdominal tip, often with inner emargination
at apex and with discal and basal cells; fore tarsus
two-segmented.
Diagnostic characters for the species Stenolemus crassirostris
such as: hairy body, general coloration (Image 2A), petiole of pronotum distinctly shorter than anterior lobe, pronotal posterior lobe with a pair of widely rounded
tubercles (Image 2B), forewing extending much beyond abdominal tip (Image 2C)
and presence of typical dark brown spots on forewing (Image 2F), foreleg
coloration and spines (Image 2D,E), close up of foreleg spines (Image 2G), mid
and hind legs with long setae of uniform density and with dark annuli, lacking
dense tufts of dark hairs (Image 2H), etc., are shown here. These characters and structure of the
phallus, as illustrated by Cai & Xiong (1996), are matching
with the images given here. The colour pattern on forewing, seen in our specimen, is also
similar to that shown by Distant (1904), as is evident from the photo of a live
specimen and full dorsal view presented here.
The Pygophore of this
species is very small, less than 1mm long, oblong oval and with long setae, parameres and preceding
segments also have long setae. Parameres are moderately long, apically curved, as seen in
situ (Image 3A,C). Phallus is
clearly seen, even in undissected pygophore,
in this lateral view due to KOH treatment (Image 3B). Posterior border of pygophore
has a plate like process which is broadly bilobed,
and seen clearly in dorsal view of pygophore, after
removal of the proctiger (Image 3C). Phallus in dorsal view (Image 3D),
lateral view (Image 3E) and in full flat view (Image 3F), as well as parameres (Image 3G) are also very similar to that shown by
Cai & Xiong (1996) for S. crassirostris,
confirming identity of our specimen.
All measurements given below are in mm. Male and
female measurements are separated as male / female.
Total length from head to tip of forewing: 7.5/7.0.
Total length of head - 0.75/0.70, anteocular part - 0.18/0.12, postocular
part - 0.25/0.20, head breadth at the level of eyes - 0.65/0.65, interocular distance
- 0.30/0.30; antenna: length of I segment of antenna - 2.62/2.72, length
of II segment - -/2.12, length of III segment - -/0.37, length of IV segment -
-/0.95; labium: total length of labium - 0.96/0.90, length of I visible segment
of labium - 0.40/0.37, length of II segment- 0.25/0.22, length of III segment-
0.31/0.31; pronotum length dorsally - 1.64/1.52, (fore lobe -
0.52/0.37, petiole- 0.25/0.17, hind lobe- 0.65/1.0), pronotum
breadth at humeral angles - 1.0/1.0; abdomen length - 2.75/1.25; length of
hemelytra - 5.5/5.5; fore leg, (lengths): coxae -
0.62/0.75, femur- 2.07/2.07, tibia - 1.62/1.62, tarsus with claw - 0.27/0.30;
mid leg, (lengths): coxae- 0.25/0.37, femur -
3.50/3.75, tibia - 5.0/4.50, tarsus
with claw- 0.25/0.32; hind leg, (lengths): coxae -
0.38/0.37, femur - 5.37/6.12, tibia - 7.62/7.25, tarsus with claw-
0.30/0.32. Male phallus: total
length of phallus (everted and flattened as shown in
figure) - 0.62;
paramere - 0.35.
Genus: Gardena
Dohrn, 1860.
Gardena
brevicollis Stl, 1871
The genus Gardena can be identified by
characters such as: the first visible labial segment much shorter than second
visible segment; mesonotum as well as and metanotum without any spines; anteroventral
series of fore femur composed only of fine, spine like setae; fore wings with a
single large discal cell, etc.
The species Gardena brevicollis
can be identified on the basis of body size; pronotal
coloration and length (Image 4A,B), shape of head, neck and labial segments
(Image 4C,D) and presence of deep transverse notch between anterior and
posterior lobes of pronotum (Image 4E). Close up photos of head, pronotum and prosternum, along
with coloration of coxae and trochanters of mid-hind
legs (Image 5A,B,C) indicate similarity with what was
described as Gardena fasciata by Distant
referred above. Forewing image
shows details of venation, (Image 5D) and spineless nature of the basal 1/4th
length of fore femur is shown in (Image 5E), both matching with the
illustrations given for this species by Wygodzinsky
(1956).
Note dorsally nearly flat head as well as
relative proportion of head with entire pronotum,
large eyes, transverse sulcus between eyes and slightly swollen second visible
segment of labium, distinct notch between anterior and posterior lobes of pronotum (Image 5C) and somewhat shining body. Also visible
is sub apical ochraceous annulation on fore femur in
(Image 5E).
In this species the last tergite
is subtriangular, slightly obliquely raised above
abdomen and just overlapping distal tip of pygophore
(Image 6A,C), barely showing parameres from dorsal
side. Pygophore
is longer than broad, ventrally very convex (Image 6B,C) and dorsally flat,
considerably sclerotized and opaque, even after KOH treatment (Image 6D). Pygophore has
distinct, vertical, spiny process at posterosuperior
tip that is clearly visible after removal of parameres
(see inset of Image 6E). Parameres are long, slender in basal half, slightly clavate and very setose in distal
half (Image 6F). Phallus is shown
here in fully everted position showing short and
stout articulatory apparatus, as mentioned by Wygodzinsky
cited above (Image 6G). This is
also a species rich, cosmopolitan genus with about 50 species known from all
zoogeographical regions.
Gardena brevicollis measurements,
given below, are in mm.
Total length 12.8, one male. Head length 1.25, anteocular
dorsally visible part 0.50, postocular dorsally
visible part 0.57, head breadth between eye 0.42, head breadth at eye 0.85;
antenna: length of I segment of antenna 6.4, length of II segment 6, length of
III segment 0.32, length of IV segment 1.76; labium: total length of labium
1.32, length of I segment of labium 0.25, length of II segment 0.375, length of
III segment 0.70; length of anterior lobe of pronotum
1.62; length of posterior lobe of pronotum 1.37;
breadth at anterior angle of pronotum 0.50; breadth
at humeral angles 0.87; abdomen: total length of abdomen 8.4, maximum breadth
of abdomen 0.87; wing: forewing length 7.6; fore leg, (lengths): coxae 2.4, femur 4.0, tibia 2.24, tarsus with claw 0.40;
mid leg, (lengths): coxae 0.50, femur 10.88, tibia
15.2, tarsus with claw 0.40; hind, (lengths): coxae
0.50, femur 8.4, tibia 10.4, tarsus with claw 0.40; pygophore:
length of pygophore 0.75, height at base 0.50,
breadth dorsally 0.42; pygophoral spine height 0.12;
phallus- total length of phallus (everted and flattened
as shown in figure) 1.31, paramere length 0.43.
Discussion
Stenolemus crassirostris was
originally described briefly by Stl
(1871). Distant (1904) later
reported this species from Ceylon (now Sri Lanka) and also gave a slightly
extended description and habitus drawing; Cai & Xiong (1996) subsequently redescribed
in more details and provided measurements and additional diagrams including
those of parameres and phallus for the first time,
based on specimens from China.
Recently Rdei & Tsai (2010) reported this
species from Taiwan, gave diagnostic features and stated the distribution to
be: ÔPhilippines, Sri Lanka, China and TaiwanÕ. A report also states presence of this
species in northern Sumatra (Arnold 1991).
Until now only four species of Stenolemus were known from India: Stenolemus atkinsoni
Distant, 1903; Stenolemus greeni Distant, 1903; Stenolemus
hirtipes Distant, 1919 and Stenolemus
susainathani Wygodzinsky,
1966 (see Ambrose 2006) and a fifth was added to this list, as Stenolemus annulatus
Mukherjee, Ambrose, Hassan & Biswas, 2015
(Mukherjee et al. 2015). Stenolemus crassirostris
thus becomes the sixth species under this genus in India.
S. crassirostris
differs from other indian species in having the
shortest ÔpetioleÕ of pronotum and in not possessing
tufts of black hairs on dark annuli of mid and hind legs; besides the pattern
of coloration on forewing of S. annulatus, S.
susainathani and S. greeni
is entirely different. S. hirtipes is 11mm long and has
Ôlongly piloseÕ mid and
hind legs as per original description (Distant 1911); S. greeni
is about 10mm. Keys
for already known species of Indian Stenolemus
were provided by Mukherjee et al. (2015)
Gardena brevicollis is a
very widely distributed species in the oriental region and also occurs in
Australian region, in some parts of Russia, Korea and Japan (Wygodzinsky 1966, Ishikawa 2005, Rdei
& Tsai 2010). Gardena specimen
was initially identified as Gardena fasciata Distant,
1909, because the characters were matching with the original description, and
subsequent redescription, with habitus drawing
(Distant 1909, 1910). McAtee & Malloch (1926) also
gave brief comments on colouration of Gardena brevicollis.
Wygodzinsky (1966), in a monograph on world Emesinae, synonymized Gardena fasciata
with Gardena brevicollis and stated: Ōnothing
in DistantÕs description and figure of his fasciata distinguishes it from brevicollis. The color pattern of the thorax,
as described by Distant, is typical of well- preserved specimens of brevicollisĶ.
Earlier, Wygodzinsky (1956) had also
synonymized Gardena australis Horvath, 1902
with Gardena brevicollis; these two papers by Wygodzinsky give illustrations of important diagnostic
characters of Gardena brevicollis (such as
fore femur and its spine, pygophore and phallus) and
those were useful in confirming the identity of species.
Recently Ishikawa (2005) studied the species of
the genus Gardena found in Japan, including Gardena brevicollis; in the same paper Ishikawa described a new
species as Gardena albiannulata Ishikawa, 2005
from Japan. Based on its
description and illustrations given by Ishikawa (2005), we feel that it is also
very similar to Gardena fasciata Distant and
hence likely to be a synonym of Gardena brevicollis. Dr. Ishikawa (in personal communication
with H.V. Ghate, August 2017),
has also expressed this possibility; however, re-examination of additional
specimens (from India and Japan) may be necessary for deciding the status of Gardena
albiannulata. Rdei &
Tsai (2010) also reported Gardena brevicollis
as well as Gardena albiannulata from
Taiwan. It should be noted that Gardena
brevicollis is widespread and also a variable
species with respect to coloration and for this reason Gardena australis Horvath and Gardena fasciata
Distant have been synonymised with Gardena brevicollis (see Wygodzinsky
1966).
Recently an apterous
form of Gardena melinarthrum Dohrn, 1859 was reported from Jalpaiguri
District, West Bengal (Mukherjee & Saha 2017) but
this paper is illustrated with images (of male and female) that do not show any
structural details. On the basis of
size alone (reported length for male 10mm and female 15mm) we feel that this
material must be re-examined because, as per the key and description of melinarthrum group of Wygodzinsky
(1966), Gardena melinarthrum is Ōmedium to
large (18.5 to 25 mm), winged or apterousĶ insect; so
it is likely that Mukherjee and SahaÕs species is
something else. The only other
species said to be present in India is Gardena muscicapa
(Bergroth, 1906) as mentioned in the checklist of
Ambrose (2006); however, there are no further reports or good photographs /
illustrations of this species from India.
Gardena bicolor Distant, 1903, described from Burma (=Myanmar),
and so likely to be present in India, has been treated as a possible synonym of
Gardena melinarthrum (see: Wygodzinsky
1966). Most species of Emesinae found in India are poorly studied and need
well-illustrated redescriptions so that those can be
identified unambiguously. One such redescription of an apterous emesine bug, Ploiaria anak, has recently been completed (Pansare
et al. 2018) and a few more will be presented in due course.
The presence of the two Emesinae
reported here, namely Stenolemus crassirostris and Gardena brevicollis,
in India is not surprizing because many insects
are common to India and Sri Lanka.
What is surprising is that these have never been reported from India so
far. A recent report of another emesine bug Myiophanes greeni Distant, 1903 from Maharashtra (Kulkarni & Ghate 2016), indicates
that emesine bugs originally described on the basis
of specimens from Ceylon are also likely to be present in India. According to Wygodzinsky
(1966) Gardena and Stenolemus are two
of the four genera that are cosmopolitan with Ôspecies in each of the six
traditional zoogeographical regionÕ.
Thus, In spite of delicate appearance and small size, many emesines are widespread.
It is well known that many species of Stenolemus are found in and around spider webs and some actually feed on spiders, as has been described by other
workers (Wygodzinsky 1966; Wignall
& Taylor 2010; Soley et al. 2011). It would be interesting to study the
biology of this and other species of Stenolemus
in India.
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