Diversity of aquatic and semi-aquatic Heteroptera (Insecta: Hemiptera) of the four lotic systems of Cachar district of Assam, India.
Assam University SilcharAuthors
Anupama Saha And Susmita Gupta Department Of Ecology And Environmental Science, Assam University Silchar.
Introduction: What conservation problem or question does your study address?
Heteropterans acts as biomonitors, bioindicators, predators and bio-control agents. Cachar district in the Barak Valley region of Assam, is a part of Indo-Burma biodiversity hotspot and is rich in wetlands, ponds and tributaries of the principal River Barak. Four lotic systems, river were selected in the district for the study. This study aim to explore and report different aquatic and semi aquatic Heteropterans in the rivers during four seasons of the year 2013-14.
Methods: What were the main research methods you used?
Standardised “all out search” method was used to collect the samples in streams. Samples were taken within 10 m2 area for one hour. Within sampling area, Hemipterans were searched in all the possible substrata such as bedrocks, boulders, cobbles, leaf litter, dead wood, bottom mud, etc.. Floating, submerged and marginal vegetation were also thoroughly observed for Hemipterans. And in rivers where the water flows with little turbulence over gravel and sand, Hemiptera were sampled by taking three, 1-minute ‘kick-net samples’ (mesh opening: 180 μm; area 1m2). The kick-net is held against water current and an area of 1 m2 in front of the net is disturbed for one minute. The same procedure is followed in all the sites during all four seasons. The samples were then preserved in 70% ethanol and Taxonomic identification was carried out by using standard keys. Same procedure is followed during four seasons of the year 2013-14
Results: What are your most important results?
The study records 2 infraorders, 10 families and 29 different species of Heteroptera insect community in different seasons in the 4 lotic systems. The Hemipterans families recorded in the system were Octheridae, Corixidae, Nepidae, Notonectidae, Gerridae, Mesoveliidae, Veliidae, Naucoridae, Pleidae and Belostomatidae. The lowest number of Hemiptera families was recorded during the pre-monsoon season compared to other seasons.
Discussion: What are your important discussion points and what is the relevance of your results to conservation (if any)?
In India there are several studies on aquatic insect diversity, distribution and abundance but studies specifically on diversity, distribution and abundance of aquatic and semiaquatic heteropterans are a few, mostly confined to Peninsular India and In N.E India studies are scanty. Information on the biota is a prerequisite for undertaking appropriate conservation strategies and has been emphasized in the Convention on Biological Diversity (CBD) held in 1992.