International Journal of Zoology Studies 11 International Journal of Zoology Studies ISSN: 2455-7269; Impact Factor: RJIF 5.14 Received: 13-11-2018; Accepted: 17-12-2018 www.zoologyjournals.com Volume 4; Issue 1; January 2019; Page No. 11-16 An investigation on biodiversity of aquatic insects in Sagar Lake Anjana Choudhary 1 , Janak Ahi 2 Department of Zoology, Dr. Hari Singh Gour Vishwavidyalaya, Sagar, Madhya Pradesh, India Abstract Sagar Lake is located in the centre of Sagar city in Madhya Pradesh. This lake is surrounded by agricultural fields, industries, hospital, bus stand and slums. The waste from the industries and surrounding localities is directly discarded into the lake. To evaluate the water quality of this lake, study was carried out for the period of two year from July 2013 to June 2015. Monthly water samples and aquatic insects were collected to analyse different physico-chemical parameters and diversity indices. The status of lake was investigated on the basis of obtained results of physico-chemical parameters of water and diversity indices of aquatic entomofauna. Keywords: Sagar Lake, industries, localities, water samples, physico-chemical parameters, water quality, aquatic entomofauna Introduction Biodiversity includes species variation, ecosystem variation and genetic variation in a particular environment while aquatic biodiversity includes the variety of life within aquatic ecosystem. According to Tachet et al. (2003) [18] aquatic water bodies are under various kind of stress caused by anthropogenic activities. This situation threatens both aquatic living resources and human population Ramade (2002) [15] . Biodiversity loss in freshwater ecosystems is an increasing phenomenon mainly due to human activities Abell (2002) [15] . Insects are habitat specialists as they are present in some extent nearly in every single type of habitat and are frequently good indicators Ganai (2011) [24] , Lewis and Gripenberg (2008) [13] . Removal or loss of aquatic insects can cause negative effects in the eco-systems stability and diversity Krishnan et al. (1988) [12] . Standard physico-chemical water quality methods are carried out in conjunction with biomonitoring tools to comprehensively evaluate the health of freshwater ecosystems Subramanian and Sivaramakrishnan (2007). Sagar city is situated around a huge lake called ‘Lakha Banjara’ or ‘Sagar Lake’. Organic matters including suspended solids and nutrients connect the lake through drainage system. Sagar Lake is also a significant area for the anthropologic activities like bathing, boating, washing clothes and entertainment etc. as it is situated at the center of the city. In this way contamination of Sagar Lake is due to arrival of waste water and human actions which displays high level of biological wastes leading for deterioration of water quality, high productivity and decline biological diversity. Due to insufficient studies on limnological characteristics of Sagar Lake and aquatic insects an inclusive study was made to evaluate the current state of water quality. In this paper an attempt has been made to understand how sensitive and tolerant species of aquatic insects reflect status of water quality of Sagar Lake which receives many effluents from different sources. Materials and Methods Study Area Study was conducted in Sagar Lake which extends over an area about 400 acres. Sagar Lake is located at the centre of Sagar city with a range of 82 hectares (23 50 Minutes N: 78 45 Minutes E and 517 MSL). The Lake has periphery of 5230 m with maximum length 1247 m, width 120 m. Mean depth of the Lake is 2.48 m with maximum depth of 5.3 m at full tank level. According to Mishra (1969) [14] Sagar Lake is a shallow rained lake with a small catchment area of 588 hectares and commonly organized by north westward drainage arrangement of district. The lake is popularly known as “Lakha Banjara” is divided into two parts, the main lake with spread area of 1.1848 ha. and small wetland with water spread area of 0.4046 ha. The catchment area of the lake basin is 1817 ha. out of which the total water spread area is 145 ha.The main lake is well protected by a large number of ghats, houses, roads and a stone fencing wall all around, except on the southern open side which ultimately terminates in the small wetland which is connected to the main lake by a narrow passage through the earthen bound. Sites selection for samples collection In the present investigation a survey of physico-chemical parameters and aquatic entomofauna of the lake were studied for two calendar years from 2013 to 2015. Eight sites were selected for the present study, four sites from main lake and four from small wetland, which are given below :- 1. Dhobi Ghat 2. Brindavan Bagh Nalla 3. Ganga Mandir 4. Mahalwar Mandir 5. Kanera Feeder Canal 6. Baghraj Canal 7. Fisheries Department 8. Khari Nala