Additions to the Odonata
(Insecta) of Goa
Parag Rangnekar 1,
Manoj Borkar 2 & Omkar Dharwadkar 3
1 Bldg 4, S-3, Technopark, Chogm
Road, Alto-Porvorim, Goa 403001, Tamil Nadu
2 HoD, Department of Zoology,
Carmel College for Women, Nuvem, Salcette, Goa, India
3 Flat No. F-2, First Floor, Kurtarkar
Commercial Arcade, Kaziwada, Ponda, Goa 403401, India
Email:1 paragrangnekar@yahoo.com
Date of publication (online): 26 April 2010
Date of publication (print): 26 April 2010
ISSN 0974-7907 (online) | 0974-7893 (print)
Editor: K.A. Subramanian
Manuscript details:
Ms
# o2286
Received
19 August 2009
Final
received 17 December 2010
Finally
accepted 08 February 2010
Citation: Rangnekar, P., M. Borkar & O. Dharwadkar (2010). Additions to the Odonata (Insecta) of Goa. Journal of Threatened Taxa 2(4): 805-814.
Copyright: © Parag Rangnekar, Manoj Borkar & Omkar Dharwadkar 2010. Creative Commons Attribution 3.0 Unported License. JoTT
allows unrestricted use of this article in any medium for non-profit purposes,
reproduction and distribution by providing adequate credit to the authors and
the source of publication.
Author Details: Parag RangnekarAuthor of book “A Photographic Guide to the Butterflies of Goa” and the State
Co-ordinator (Goa) of the Indian Bird Conservation Network (IBCN) co-ordinated
by BNHS and Birdlife International. Employed with Mineral Foundation of Goa, a NGO set-up by the
mining industry in Goa, as Programme Manager with responsibilities of
designing, planning and executing development programmes to address social and
environmental issues concerning the communities residing in the mining belt of
Goa. Dr. Manoj Borkar Associate Professor and Head, Dept. of
Zoology, Carmel College of Arts, Science and Commerce for Women, Nuvem. Member of State Level Expert Committee for Critical Wildlife
Habitat and State Wildlife Advisory Board. Omkar Dharwadkar Founder
Member of Mitra, an NGO working towards documentation of fauna and environment
education in schools. Presently pursuing his 2nd year B.E. (Computer
Science) at Rayeshwar Institute of Technology, Shiroda
Author Contribution: PR Data collection, identification of specimen,
photo-documentation and manuscript writing; MB Identification of specimen and
editing of manuscript; OD Data collection, identification of specimen and
photo-documentation.
Acknowledgements: The
authors are grateful to Raju David, Naturalist, Taj& CC Africa for help in identification of cryptic species and to all those
who accompanied us and shared the labour of field work.
Abstract: The study reports the results from surveys for Odonates in the
State of Goa over 19 months during 2007-2008. A total of 66 species of Odonates were documented with 34
new species records from the State. The present study has resulted in an increase of 47.30% in the number of
species reported from Goa to 74 from the existing 39. Family Libellulidae dominated the odonate community with 32
species followed by Coenagrionidae with 14 species. Orthetrum sabina was the most abundant species while seven species were
documented only once during the survey period. More survey effort are needed to
completely document the odonate species diversity of the state.
Keywords: Anisoptera, Goa, new records, Zygoptera
For images & table – click here
Introduction
Goa
lies between latitudes 14053’-15048’N & 73045’-74024’E,
covering an area of 3,701km2. Tucked between the Western Ghats and the Arabian Sea, it has a warm
tropical climate with temperature ranging from 310C to 210C. Humidity throughout the year is high,
the average being 86%. The
southwest monsoons operate over the entire state registering an annual rainfall
of around 300-400 cm.
The
complete eastern stretch is under legal protection in the form of four wildlife
sanctuaries and one national park. Serious taxonomic work to document the diversity of this small state
though, has been found wanting. Sporadic efforts limited to certain taxa have been carried out by
researchers and premier organizations like the Zoological Survey of India. Unfortunately, with the exception of
Lepidoptera (Rhophalocera) and to some extent Odonata and Arachnida, other
lesser known fauna have been neglected. For that matter, earlier studies on Odonata of the
state were based on limited samples and does not cover the entire state
and all seasons (Prasad 1995).
The
Odonata diversity is well documented from the rest of the country after the
pioneering work by Fraser (1936). The first peer reviewedwork for the State of Goa was by Prasad (1995) wherein 22 species of Odonates
were reported. The Fauna of Goa:
State Fauna Series (2008) by Zoological Survey of India added another 17
species to the list by Prasad, thereby increasing the
total species count to 39. In
between these two reports Borkar et al. (2006) gave an account of Odonata in
the campus of the Carmel College for Women in Salcette Taluka wherein 16
species not reported earlier were reported. This paper somehow did not figure in the compilation by the
Zoological Survey of India, thereby ten species new to the state were not
reported in the State Fauna Series, an anomaly that needs to be taken
cognizance of for realistic assessment of status of odonate diversity.
A
total of 499 species and subspecies of Odonata are known to occur in India
(Prasad & Varshney 1995) out of which about 200 species are recorded from
peninsular India, thereby highlighting the fact that the 39 species recorded
for the state is an underestimate.
The
present paper provides updated information on the diversity and distribution of
Odonata of Goa, based on extensive surveys from May
2007 to December 2008. The need to
address gaps in information on Odonate diversity of Goa has been highlighted in
the Goa State Biodiversity Strategy Action Plan (GSBSAP)
Methods
Surveys
were conducted throughout the state to cover varied habitats ranging from
mountain streams, inland water bodies, paddy-field to
marsh lands. The locations visited
and the associated habitats are presented in Table 1. The survey locations are also marked on the state map for
easy reference (Image 1).
A
total of 38 surveys were conducted in these locations to document the Odonata
diversity. Observations were done
over three seasons: Monsoons (June - September), Winter(October - January) and Summer (February - May) in the year 2007-08. Individual specimens were
photo-documented from various angles and these images were cross-checkedwith identification manuals for identification. Collection and killing was avoided for species
which could be visually identified. For difficult species, specimens
were caught using sweep nets and collected in paper envelopes. The specimens were kept alive to let
them excrete and clear their gut before being treated in acetone solution at
the end of the day. Larger species
were treated for 10-12 hours while smaller species, especially damselflies were
treated for 7-8 hours before drying in the shade and then preserved in
air-tight plastic envelopes properly labeled with the name of collector, date
of collection, habitat and in few instances the latitude and longitude
co-ordinates. The collected
specimens were identified using standard field guides (Fraser 1933, 1934, 1936;
Subramanian 2005). Systematic
arrangement of the species follows Subramanian (2009).
Occurrence
frequency was calculated by plotting the occurrence of individual species at
the each sampling locations. A
presence-absence matrix gave an indication of the most abundant species over
the sampling locations and over varied habitats.
Results
and Discussions
In
the field study spanning 20 months, 66 species of odonates belonging to 12
families were documented from Goa. The results are presented in Table 2. In Zygoptera, the family Coenagrionidae dominated the list
with 14 species followed by Calopterygidae (3), Platystictidae (3),
Platycnemididae (2), Chlorocyphidae (2), Protoneuridae (1), Euphaeidae (2) and
Lestidae (1) (Fig. 1). In
Anisoptera, the family Libellulidae dominated the list with 32 species followed
by Gomphidae (3), Aeshnidae (2) and Cordulidae (1) (Fig. 2). Of all the families, the maximum
contribution to the species diversity was found in Libellulidae accounting to
47.76% followed by Coenagrionidae which contributed
20.89% of the total species. This
is a general trend which can be attributed to the
presence of habitat generalist species in the above families.
The
most significant finding has been reports of 34 species and four families for
the first time from the state of Goa. Three Species reported by Borkar et al (2006) but not reported by
ZSI or documented during the present study have not been included since they
were documented prior to the present investigation period and hence are beyond
the scope of the present study, though itis felt that the findings have significant scientific value. The four new families viz.,
Platystictidae, Euphaeidae, Cordulidae, Aeshnidae include species
which are mainly found in and around water bodies in areas with good
forest cover. The absence of
species representing these families in the previous studies suggests
overlooking of such areas in the surveys, which is evident from the locations
mentioned in the respective papers. The present study has resulted in a
staggering increase of 47.30% in the number of species reported from the Goa to
74 from the existing 39. The new
records are marked with an asterisk in Table 2.
Orthetrum sabina was the most abundant species with an occurrence frequency of
81.25% followed by Diplacodes trivialis & Pantala flavescens (75%). Orthetrum glaucum was a close fourth with an
occurrence frequency of 50%. These
results indicate a fairly well distributed population of the above species in
the entire state and also in varied habitats. Seven species viz., Mortonagrion varalli, Agriocnemis splendidissima, Agriocnemis femina, Hylaeothemis
indica, Idionyx saffronata, Neurothemis intermedia, Palpopleura sexmaculata were documented only once during
the survey period. The details are
shown in Table 2.
Table
1 indicates that the maximum diversity was observed at Bondla (25 species)
followed by Paytale (23) and Derode (22). This could also be attributed to the survey effort since at all these
sites maximum surveys were conducted (4 times). Paytale and the surrounding areas in Ponda Taluka are of
conservation importance since the site not only holds a good diversity of
odonates but two of the seven species documented only once during the period
were documented from this site.
It
was also observed that the maximum diversity was found during the monsoon
season wherein 46 species were documented followed by winter (43) and summer
(29). This is in accordance with
the life history of odonates and their dependence on water bodies. Idionyx saffronta and Mortonagrion varalli were recorded only in the monsoons, Palpopleura sexmaculata was recorded only in winter, while Lathresticta asiatica was recorded only in summer. The Kerala Dartlet Agriocnemis cf. keralensis hitherto known and reported only from Kerala where it was
considered endemic, has been documented from the state, thereby indirectly
suggesting its presence in the states of Karnataka and Tamil Nadu. This species
was identified in consultation with David Raju, Naturalist, Taj& CC Africa.
ExceptAciagrion
hisopa, Aciagrion pallidum, Agriocnemis lacteola, Enallagma parvum, Pseudagrion
malabaricum, Ellatoneura tetrica and Lestes viridulus listed by Kulkarni & Talmale (2008) from the Fauna of Goa,
all other species were recorded in the present study.
Though
the present study covers varied habitats in the state of Goa, the authors are
conscious of the fact that more extensive surveys are needed along the water
bodies throughout the state and especially in the network of protected areas to
understand seasonality and flight periods. Biodiversity surveys still largely focus on larger animals,
especially vertebrates and even the biodiversity hotspot status of the Western
Ghats is based largely on data pertaining to vertebrates and flowering plants,
as data on invertebrates is insufficient or non-existent (Meyers et al. 2000). The present work is expected to be the
foundation on which academicians and researchers will undertake more systematic
surveys and studies on habitat requirement of these “indicator” species.
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