Aquatic Insect Diversity of Baitarani Estuary of Odisha - Aquatic Ecosystem: Biodiversity, Ecology and Conservation - page 91

The aquatic insects are taxonomically diverse
and fascinating in structure and biology, and
some of them have great importance to public
health and aquaculture. The aquatic insect may
be considered model organisms in analyzing the
structure and function of the inland waters
because of their high abundance, high birth rate
with short-generation time, large biomass and
rapid colonization of freshwater habitats. They
constitute a dominating group of benthic, lim-
netic and littoral fauna of aquatic ecosystems
(Sharma and Agrawal 2012 ).
Aquatic Hemiptera holds an important posi-
tion in the ecology of aquatic ecosystem (Hazarika
and Goswami 2010 ). Certain families of the bugs
are utilized in the biological control of mosqui-
toes larvae (Ohba and Nakasuji 2006 ; Saha et al.
2007 ). Out of 11 globally recognized families,
fi ve major families of true aquatic bugs belong
to infra order Nepomorpha (Belostomatidae,
Corixidae, Notonectidae Naucoridae and
Nepidae) are chiefl y represented from India. They
are characterized by their short antennae that are
usually hidden. Nepomorpha bugs occupy diverse
ecological niches ranging from saltwater pools to
torrential streams and rivers. In India, fi ve fami-
lies of aquatic Coleoptera belong to 55 genera,
and only 210 species are known till now. The ear-
lier knowledge and scientifi c contribution on
aquatic beetles (Vazirani 1977 , 1973 , 1984 ;
Deepa 2010 ) are noteworthy to understand the
present fauna. The major studies on aquatic
Coleoptera also include the works of Jäch ( 1998 ),
Balfour-Brown ( 1939 ) and Mukhopadhyay and
Ghosh ( 2003 ); Michael et al. ( 2001 ).
The entomofauna of estuaries in India is rather
poorly documented, and limited number of stud-
ies has been carried out on the ecological aspects
of this group. Few studies (Chakraborty and
Naskar 1988 ; Chakraborty 1996 ; Khan 2002 ;
Subramanian and Sivaramakrishnan 2007 ) on
estuarine Hemiptera group have been carried out
on some specifi c wetlands in India. In the above-
mentioned context, the present study was carried
out with the objective to identify the commonly
occurring insect fauna of this estuary which has
not been studied so far in detail. The systematic
list of distribution of aquatic Hemiptera and

Coleoptera of Odisha has been given in the
present paper, and systematic account of the
species identifi ed during the study has been
incorporated.

Methods

The present study was carried out during April
2008 to March 2009 in selected localities of
Brahmani-Baitarani estuarine ecosystems
(Figs. 7.1 and 7.2 ). In order to cover maximum
part of the water bodies, seven spots on the estu-
ary and upper river stream were selected for col-
lections. Collections of insect were made with
help of hand-operated nets of varying sizes
depending upon the area of the water bodies. The
design and operation of the nets was approxi-
mately based on those described by Junk ( 1977 ).
Insects collected for study were preserved in
70 % alcohols. Only Hemiptera and Coleoptera
collections were identifi ed by using the standard
literature on the group (Thirumalai 1994 , 1999 ,
2007 ; Deepa and Rao 2007 ; Bal and Basu 1994a ,
b ). The physicochemical parameters were taken
from all the sites. The water surface temperature
ranged from 26 to 28 °C and sub-surface data
ranged from 25 to 27 °C. The pH of water ranged
from 6.9 to 7.4 and salinity ranged from 4 to 14 ppt.

Systematic List: Hemiptera

ORDER: HEMIPTERA
Suborder: Heteroptera
Infraorder: Nepomorpha Popov, 1968
Superfamily: Nepoidea Latreille, 1802
Family: Nepidae Latreille, 1802
Subfamily: Nepinae Latreille, 1802
Tribe: Nepini Latreille, 1802
Genus: Laccotrephes Stal, 1866
Subgenus: Laccotrephes Stal, 1866
1 . Laccotrephes griseus (Guerin-Meneville, 1844)
2 . Laccotrephes ruber (Linnaeus, 1764)
Subfamily: Ranatrinae Douglas & Scott, 1865
Tribe: Ranatrini Douglas & Scott, 1865
Genus: Ranatra Fabricius, 1790
Subgenus: Ranatra Fabricius, 1790