Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 July 2020 | 12(10): 16392–16395
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
doi: https://doi.org/10.11609/jott.5834.12.10.16392-16395
#5834 | Received 04 March 2020 | Final
received 07 April 2020 | Finally accepted 23 June 2020
Observations of the damselfly Platylestes cf. platystylus
Rambur, 1842 (Insecta: Odonata: Zygoptera:
Lestidae) from peninsular India
K.J. Rison 1 & A. Vivek Chandran 2
1 Konkoth House, Thumboor
P.O, Thrissur District, Kerala 680662, India.
2 Department of Geology and
Environmental Science, Christ College, Irinjalakuda,
Thrissur, Kerala 680125, India.
1risonkj@gmail.com, 2avivekchandran@gmail.com
(corresponding author)
Editor: Raymond J.
Andrew, Hislop College, Nagpur, India. Date
of publication: 26 July 2020 (online & print)
Citation: Rison, K.J. & V. Chandran (2020). Observations of the damselfly Platylestes cf. platystylus
Rambur, 1842 (Insecta: Odonata: Zygoptera:
Lestidae) from peninsular India. Journal of Threatened Taxa 12(10): 16392–16395. https://doi.org/10.11609/jott.5834.12.10.16392-16395
Copyright: © Rison & Chandran 2020. 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: None.
Competing interests: The authors
declare no competing interests.
Acknowledgements: We thank Jeevan Jose and Noppadon Makbun for their
assistance in identifying the species; the Society for Odonate
Studies (SOS), Kerala for the constant encouragement and technical
support. We are grateful to the IUCN Red
List for permitting to use the species distribution shape file of Platylestes platystylus.
Lestidae is a rather small family of
cosmopolitan, relatively large-sized, slender damselflies (Insecta:
Odonata: Zygoptera) commonly known as spreadwings.
One-hundred-and-fifty-three species of Lestidae
from nine genera are known from around the world and India has 25 species
belonging to five genera (Subramanian 2018).
Platylestes platystylus
was described by Jule Pierre Rambur in 1842. Earlier collections of the species are from
Bengal and Myanmar (Fraser 1933). The
extant range of Platylestes platystylus is depicted by the IUCN Red List as India
(West Bengal), Lao People’s Democratic Republic, Myanmar, Thailand, and
Iraq. Though it is listed as a Least
Concern species, there is an urgent need for research regarding its taxonomy,
population size, population trends, distribution, life history, ecology, and
threats (Sharma 2010).
Multiple individuals of
unidentified female damselflies were observed and photographed by RKJ from Thommana region (10.3420N & 76.2500E)
of the Kole wetlands and Thumboor
(10.2970N & 76.2560E), a nearby village during the
period 2015–2017. Close observations of
the insect’s general body structures, wing postures, and wing positioning
habits helped us confirm that the damselflies belonged to the family Lestidae. However,
the observed individuals could not be assigned to any species as they did not
match the description, illustration or photographs of any Lestes
species known from the region. A male
individual was photographed from Thumboor Village in
September 2018 by RKJ. A female was
observed and photographed from Uppungal region
(10.6920N & 75.9970E) of the Kole
wetlands by a volunteer, Renjith R.V. during the
first Kole Odonata survey organized jointly by the
Society for Odonate Studies, Kerala Agricultural
University and Kerala Forest and Wildlife Department in October 2018. Both male and female individuals were
observed from Thommana and Thumboor
during August 2019 to December 2019 by RKJ and VCA. The species was confirmed as Platylestes cf. platystylus
after referring to Fraser (1933) and discussing with Noppadon
Makbun (10 April 2018). Since the species was observed from one of
the southernmost (Thommana) and northernmost (Uppungal) points of the Kole
wetlands, it is reasonable to assume that the species occurs in various
locations in and around Kole wetlands.
Description of adult male:
Platylestes platystylus
is a small, dull-coloured damselfly of the size of Lestes
species. Like other members of Lestidae family, it holds its stalked, clear wings spread
out at rest. Eyes are of bright green
colour. The labium is dirty yellow and
the labrum, bases of mandibles and cheeks are
olivaceous in colour. Its prothorax and
thorax are light green, paler at the sides and pruinosed
white beneath. The thorax has several
black spots. Its wings are palely enfumed. The
quadrate pterostigma (wing spots) of Platylestes
platystylus with pale or white inner and outer
ends help distinguish it from Lestes species
for which the more elongate pterostigma are of uniform colouration (Table
1). Its abdomen is olivaceous to warm
reddish-brown in colour with black apical rings on each segment. Anal appendages are whitish with the
superiors black at base, curling in at apices to meet each other. Inferior appendages are about half the length
and thick at base.
Description of adult female: Female closely resembles the
male in most aspects. Anal appendages
are yellow, blackish-brown at the base, and as long as segment 10 of the
abdomen.
Immature individuals have pale
khaki brown thorax and eyes, but the black spots on thorax are distinctive.
Odonatological studies in the
Western Ghats have not recorded Platylestes
platystylus till date (Emiliyamma
2014; Subramanian 2018). We made 20
observations of the species during the period 2015–2020, all from submerged
paddy fields. We made field visits twice
every month, but could observe the adults only during the period of
June–December. Mating and egg-laying
were observed in the months of October and November. The females after mating
laid their eggs in grasses emerging from water, unguarded by the males. Teneral individuals
(newly emerged adults) were also observed, highlighting the importance of this
wetland as their breeding habitat. The
species is highly seasonal and no adult could be observed during the period
from January to June. Fraser (1933) has
stated that it is possible that more than one species exists among the four
specimens he examined, emphasizing the need for further taxonomic study of the
species.
The Kole
wetlands is a low-lying area that remains submerged under floodwater for about
six months in a year. Wetland agriculture, mainly paddy cultivation is the most
important activity undertaken here (Johnkutty &
Venugopal 1993). Kole
is a globally important wetland designated as a Ramsar
site since 2002 (Islam & Rahmani 2008), but it
faces multiple threats in the form of encroachments, waste dumping and
excessive use of pesticides. The
observation of the rare Platylestes cf. platystylus adds to the conservation value of
this wetland.
Table 1. Differences between Platylestes platystylus
and other members of Family Lestidae found in the
region.
|
Species |
Platylestes platystylus |
Lestes species |
Indolestes davenporti |
|
Position of wings at rest |
Spread out |
Spread out |
Held close to the body |
|
Thoracic markings |
Large number of black spots |
Metallic/non-metallic stripes,
few spots in some |
Striped thorax, no spots |
|
Pterostigma |
Quadrate with pale or white
inner and outer ends |
At least twice as long as
broad, uniform dark colours |
Bicolorous, three times as long
as broad |
References
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