Environmental Engineering Reference
In-Depth Information
are separated by the Ten Degree Channel which
is about 150 km wide and 400 fathoms deep.
Average annual temperature varies from 24 to
28 °C. The elevations range from 0 to 732 m
at Saddle Peak in North Andaman and 642 m
at Mount Thuillier in Great Nicobar Island.
The rainfall is slightly higher in Nicobar with an
annual average of 3,000-3,500 mm.
Dragonfl ies (Anisoptera) and damselfl ies
(Zygoptera) are one of the most easily recognizable
insect taxa, due to their large size, bright colours
and behaviour. They include the largest insect
that ever lived, the griffenfl y
Meganeuropsis
permiana
Carpenter, with a wingspan of c. 70 cm
(Kalkman et al.
2008
). Dragonfl ies are a well-
studied group of invertebrates with their increasing
recognition in conservation worldwide (Cordoda-
Aguilar
2008
; Samways
2008
). Dragonfl ies are
key organisms of the food web as predators
both as larvae and as imagoes (Benke
1976
).
They usually have defi nite habitat preference and
territorial behaviour (Corbet
1999
).
A total of 5,680 species of Odonata are
known from all over the world, of these 2,739
species belonging to the suborder Zygoptera
(19 families) and 2,941 species to the suborder
Anisoptera (12 families) (Kalkman et al.
2008
).
India has a wide variety of suitable habitats that
support large populations of Odonata and 470
species belong to 139 genera and 19 families
occur in India (Subramanian
2009
). In Andaman
and Nicobar Islands, a total of 72 species
belong to 11 families and 38 genera were
reported by various workers (Selys
1853
,
1863
,
1871
; Fraser
1933
,
1934
,
1936
; Lahiri
1975
,
1998
; Chhotani et al.
1983
; Lahiri and Mitra
1993
; Mitra and Maiti
1992
; Mitra
1995
,
2002
;
Ram et al.
2000
; Yeh and Veenakumari
2000
;
Nandy and Babu
2009
).
Methods
Field studies were conducted from 2008 through
2013 to assess the status and distribution of
odonate fauna, and also consulted with available
literature to prepare the updated checklist of this
paper. Odonates were identifi ed based on standard
systematic keys (Fraser
1924
,
1933
,
1934
,
1936
;
Subramanian
2009
; Mitra
2006
).
Species Richness and Abundance of
Odonates
Total number of odonates and
number of individuals seen in each location
were calculated using the census data and fi eld
observations.
Diversity Indices
Diversity indices were
calculated using the programme SPDIVERS.
BAS developed by Ludwig and Reynolds (
1998
).
Results and Discussion
A total of 72 taxa of Odonata were recorded in
Andaman and Nicobar Islands, these belong to
9 families and 38 genera (Table
10.1
). Of these,
the Libellulidae were the most common with
Table 10.1
List of dragonfl ies and damselfl ies of Andaman and Nicobar Islands, India
Distribution
Andaman
Sl. No.
Species name
Common name
IUCN status
Nicobar
Order Odonata
Suborder Anisoptera
Family Aeshnidae
1.
Anaciaeschna jaspidea
(Burmeister, 1839)
Rusty darner
LC
√
2.
Anax guttatus
(Burmeister, 1839)
Blue-tailed green darner
LC
√
√
3.
Gynacantha andamanae
(Yeh & Veenakumari,
2000
)
Dingy Duskhawker
-
√
(continued)
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