Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 January 2023 | 15(1): 22515–22521
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7739.15.1.22515-22521
#7739 | Received 05 November 2021 | Final
received 16 December 2022 | Finally accepted 14 January 2023
First
record of the genus Acropyga Roger, 1862 (Hymenoptera:
Formicidae: Formicinae) in
Kerala, India
Merin Elizabeth
George 1 & Gopalan Prasad
2
1,2 Department of
Zoology, University of Kerala, Kariavattom,
Thiruvananthapuram, Kerala 695581, India.
1 megkattimattom@gmail.com,
2 probios1@gmail.com (corresponding author)
Editor: Himender
Bharti, Punjabi University, Patiala, India. Date
of publication: 26 January 2023 (online & print)
Citation: George, M.E. &
G. Prasad (2023). First record of the genus Acropyga
Roger, 1862 (Hymenoptera: Formicidae: Formicinae) in Kerala, India. Journal of Threatened
Taxa 15(1): 22515–22521. https://doi.org/10.11609/jott.7739.15.1.22515-22521
Copyright: © George & Prasad 2023. Creative Commons
Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: University of Kerala.
Competing interests: The authors
declare no competing interests.
Acknowledgements: We thank the Kerala
Forest and Wildlife Department for the collection permits
(KFDHQ-3492/2019-CWW/WL10) and support during our collections. We also thank
Manoj Kripakaran and Dr. Kalesh Sadasivan, Research
Associates, Travancore Natural History Society, for their help in
identification.
Abstract: This is the first
record of the ant genus Acropyga from Kerala,
India. The ant was collected as a part of the research collections done in the Rosemala region of the Shendurney
Wildlife Sanctuary, Kerala, India. The worker, male and queen ants have been
described here. A detailed description, distribution, ecological notes, and
images are also provided.
Keywords: Acropyga
acutiventris, Shendurney
Wildlife Sanctuary, new record, Rosemala
The genus Acropyga belong to the family Formicinae
and was first reported worldwide by Roger (1862) from Sri Lanka. There are
currently 41 species in this genera worldwide (AntWeb
2018). Acropyga ants are present worldwide.
These ants are known for their mutualistic obligate symbiosis with mealybugs of
the subfamily Rhizoecinae (Johnson et al. 2001; Kishimoto-Yamada et al. 2005). They take care of these
mealybugs and feed on the exudates produced by them. They can be found in a
range of habitats, from deserts to rainforests, and is largely thought to be
subterranean (LaPolla 2004).
Major contributions
to this genus were made by Forel (1878) by making the
first description of the genus. Smith (1871) described the geographical
distribution of these ants. Terayama et al.
(2002) gave a species key to the East Asian species of genus Acropyga. Wang & Wu (1992) described a new species
of Acropyga from China and made an
identification key. Terayama (2009) gave a synopsis
of the Family Formicidae of Taiwan in which a key to
the Acropyga of Taiwan was given, along
with a few species descriptions. Jaitrong & Nabhitabhata (2005) made a list of ant species from
Thailand in which the presence of Acropyga,
along with its distribution in the country was reported. Acropyga acutiventris was
described in detail by LaPolla (2004).
Acropyga was first reported in India by Bingham (1903).
Currently, only two species from this genus have been reported in India—A. acutiventris & A. rubescens
(Bharti et al. 2016). Acropyga acutiventris has been reported from 13 states in India,
mostly from the northeastern region (Bharti et al. 2016) and Andaman &
Nicobar Islands (Mohanraj et al. 2010). This is the
first record of this genus from Kerala and the first description from India on Acropyga, including the worker, male, and alate queen. The only other state in southern India A. acutiventris has been reported is Karnataka (Varghese
2004).
Material and Methods
The specimens were
collected during the period of March 2021---–--August 2021 from the Rosemala region (8.9336N & 77.1922E) of the Shendurney Wildlife Sanctuary (Image 1). The ‘Ants of Leaf
Litter’ (ALL) protocol (Agosti et al. 2000) was used
for ant collections. These particular ant samples were collected using
handpicking. The current specimens were found under a small rock in an
evergreen forest region of the Rosemala region. A
whole colony was found under the rock, & the workers, male & alate queen, were collected. The specimens were preserved
in 70% ethanol. Identifications were done under a stereomicroscope (Labomed Luxeo 6z). The taxonomic
key by Bolton (1994) was used for the identification of the genus. The species
was identified using the key by LaPolla (2004). Leica
S8AP0 microscope with Leica DFC 295 camera was used to capture images, and
measurements were done using the Leica v4.2 software. Soil samples were
collected from the site and analysed in the
laboratory. The soil pH was analysed using a soil pH
meter and soil organic carbon was measured using Walkley & Black method
(Page et al. 1982). The soil moisture was measured using the gravimetric method
(Kadam & Shinde 2005). The specimens
were deposited in the zoological museum at the Department of Zoology,
University of Kerala Campus, Kariavattom, Kerala,
India.
Measurements
HL: Head Length.
Length of the head in full-face view when measured as a straight line from the
midpoint of the anterior clypeal margin and to the midpoint of the posterior
margin. This excludes the clypeus.
HW: Head width. The
maximum width of the head in full-face view.
EL: Eye length. The
maximum length of the eye when in the same view as HL.
ML: Mesosomal length. Length of the mesosoma in side view from
the posteroventral corner of mesosoma to the farthest
point on the anterior face of pronotum, excluding the neck.
GL: Gaster Length. The length of the gaster
in lateral view from the anterior point of the first gastral tergite to the
posterior-most point of the last gastral tergite, excluding the sting.
SL: Scape Length.
Length of the scape in a straight line excluding the basal constriction of the
neck close to the condylar bulb.
PTL: Petiole length.
Length of the petiole from dorsal view.
PTH: Petiole Height.
Height of the petiole in lateral view.
PTW: Petiole Width.
Width of the petiole in dorsal view.
TL: Total Length.
HL+ML+PTL+GL
OI: Ocular Index.
(EL/HW) x 100
CI: Cephalic Index.
(HW/HL) x 100
SI: Scape Index.
(SL/HW) x 100
DPI: Dorsal Petiole
Index. (PTW/PTL) x 100
LPI: Lateral Petiole
Index. (PTH/PTL) x 100
Results
Acropyga acutiventris Roger, 1862
Acropyga acutiventris Roger, 1862 Sri
Lanka, Indomalaya
Status as
species: Mayr, 1862: 769
Material examined:
Worker (n = 10): KUDZEN2021.X.12.a, Male (n = 1): KUDZEN2021.X.12.b, Queen (n =
1): KUDZEN2021.X.12.c Rosemala, Shendurney Wildlife
Sanctuary, Kollam, Kerala, India. 27 July 2021 at 8.9336N & 77.1922E
elevation 340 m, coll. Merin Elizabeth George, handpicking, under a stone in a
leaf litter near a small stream in a primary evergreen forest. This is a
typical specimen of the species (species typica).
Specimen deposited at the reference section of the museum at the Department of
Zoology, University of Kerala, Kariavattom,
Thiruvananthapuram, Kerala, India.
Worker: Worker
Morphometrics (in millimeters): HL: 0.83, HW: 0.987, SL: 0.81, ML: 1.024, GL:
1.50, EL: 0.125, PTL: 0.275, PTW: 0.27, PTH: 0.393, TL: 3.63, OI: 12.6, CI:
118.9, SI: 82, DPI: 98.1, LPI: 142.
Worker description:
Head: Dull yellow colour, head slightly longer than
broad and rectangular. Posterior margin of the head emarginated. Scape with
dense pubescence. Teeth five, mandibles striate from base to the articulation
point. Eyes small. Anterior margin of the mandible lined with long hairs. Head
as long as wide. Antennae 11 segmented. Eyes placed at the lower half of the
head (Image 1).
Mesosoma: Smooth and
shiny, long erect setae present on alitrunk except
propodeum. Propodeum with small recumbent hairs. Mesonotum
raised and convex above pronotum when compared to pronotum when viewed in
lateral angle (Image 2–3).
Petiole: Dull yellow,
thick and erect with short erect hairs. Height about same as propodeum.
Gaster: Five gastral segments
present, Smooth and shiny with both long erect hairs and short recumbent hairs.
Male
Male Morphometrics
(in millimeters): HL: 0.599, HW: 0.635, EL: 0.423, SL: 0.866, ML: 1.428, PTL:
0.135, PTH: 0.38, PTW: 0.12, GL: 1.458, TL: 3.62, OI: 66.61, CI: 106, SI: 136,
DPI: 88.8, LPI: 281
Description
Head: Dull yellow.
Eyes extremely large, covering most of the head, ocelli large, anterior margin
of clypeus lined with long erect hairs. Head as long as wide. Dorsal surface of
head smooth and shiny. Scape with dense pubescence. (Image 4)
Mesosoma: Dull
yellow. Smooth and shiny. Alitrunk except propodeum
with long erect hairs. Propodeum with short recumbent hairs.(Image 5–6)
Petiole: Erect and
thick with a rectangular shape. Few short hairs are present on the dorsal
surface.
Gaster: Smooth and shiny. Covered in long hairs.
Alate Queen: Queen Morphometrics (in millimeters): HL:
0.91, HW: 1.20, EL: 0.46, SL: 1.15, ML: 2.08, PTL: 0.182, PTW: 0.292, PTH:
0.65, GL: 2.98, TL: 6.152. OI: 38.3, CI: 131.8, SL: 95.8, DPI: 1.604, LPI:
357.1
Description
Head: Dull yellow.
Mandibles with striation. Anterior clypeal margin lined with long erect hairs.
Three distinct ocelli are present. Outer margin of head lined with hairs. Eyes
large placed in the lower ¼ of the head. Head as long as wide. Antennae with 11
segments (including scape) (Image 7–9).
Mesosoma: Dull
yellow, smooth, and shiny, covered in small erect hairs.
Petiole: Triangular,
erect hairs, and with small erect hairs on the dorsal surface.
Gaster: Dull yellow & five gastral segments. Surface
covered in with long recumbent hairs.
Leg: Entire leg
covered in short erect hairs.
Differential
diagnosis: This species is morphological very similar to Acropyga
rubescens, but they are generally smaller in size
and less hairy.
Diagnostic features:
Mandibles with striations from base to the articulation point.
Ecology Notes: The
ants were found in an evergreen forest, in between two stones in the leaf
litter near a small stream with low light conditions and high humidity. There
were 30 worker ants, one queen and four males in the colony. The ants were
docile upon disturbance showing few movements. There was no nest formation of
any type as the ants were found on top of a rock covered by another rock. The
ants were handpicked. There were multiple Anoplolepis
gracilipes ants a few kilometers away from the
nest. Soil was collected from where the ants were found. The pH of the soil was
measured to be 5.53. The organic matter in the soil was analysed
to be 0.04%, and the soil moisture was 24.5%.
Discussion
A total of 10
workers, one male and one alate queen were taken from
the site. These ants are relatively less common in collections because of their
rarity. This study extends the range of this genus to Kerala. A. acutiventris was observed in the Shendurney
Wildlife Sanctuary which is a part of the Western Ghats. The collections
revealed that there were multiple Anoplolepis gracilipes ants near these Acropyga
ants. The presence of invasive ants has been known to cause lowered species
diversity of ants (Berman et al. 2013). Anoplolepis
ants have also been known to cause a decrease in the diversity of ants (Mezger & Pfeiffer 2011). It can be said that the
presence of Anoplolepis ants, which act as
invaders, can be detrimental to native specialist ants like A. acutiventris. It is imperative that the forest be
protected and its human interference be lowered so that such invasive ants can
be controlled.
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