Study on the diversity of insects in kapla beel with reference to habitat utilization pattern

Abstract

1 newlineABSTRACT STUDY ON THE DIVERSITY OF INSECTS IN KAPLA BEEL WITH REFERENCE TO HABITAT UTILIZATION PATTERN Insects are the most diverse group of organisms comprising both terrestrial and aquatic forms. Insects inhabiting water for whole or part of life to complete their life cycle are commonly called aquatic insects which constitute a small fraction (about 3%) of the total insect diversity. Aquatic insects of wetland reflect as a whole the insect diversity of the wetland. The physico-chemical characteristics of water plays very important role in occurrence, distribution and abundance of insects in wetlands. Aquatic forms of life including insects and various physico-chemical parameters of water showed a relationship between them. Aquatic macrophytes play a vital role in structure and function of aquatic ecosystem. They can alter the physical condition of water bodies and increase in the heterogeneity of the habitat for aquatic macro invertebrates including insects. Aquatic macrophytes constitutes an important habitat for the aquatic organism. The insects utilize them as food source, as shelter and as breeding sites. The availability of macrophytes determine the diversity of insects fauna in different types of wetland. newlineThe present study was undertaken to find out insect diversity and their habitat in Kapla Beel, a fresh water ecosystem with the following objectives - 1. To survey the Beel and collection of insects, water samples and macrophytes , 2. To identify the collected insects and macrophytes of the Beel. 3. To analyse the Physico- newline2 newlinechemical characteristics of water of the Beel and its relation with insects and 4. To newlinestudy the habitat utilization by the insects of the Beel. newlineThe Kapla Beel is perennial open type freshwater wetland of Barpeta newlineDistrict of Assam. The geographical position of the Kapla Beel is 26o15and#8242; 26o30and#8242; N newlinelatitude and 9lo0and#8242; 91o15and#8242; E longitude. It covers an area of 91 hectares at full storage newlinelevel but at dead storage level the area is reduced to approximately 55 hectares. For newlinesampling purpose, the Beel area was divided into five zones namely North zone, South newlinezone, Central zone, East Zone and West Zone on the basis of occurrence of density of newlinemacrophytes species and presence of insects. The study was carried out for two years newlinefrom May, 2010 to April 2012, covering three seasons pre monsoon (March-May), newlinemonsoon(June-October), and post monsoon (November- February) seasons of a year. newlineStandard methods were followed in the study of insects diversity, water analyses, newlinemacrophyte study and habitat utilization by insects. newlineThe insect diversity study of the Beel revealed the presence of 46 species newlineof aquatic insects including 5 orders of aquatic insects viz. Coleoptera, Diptera, newlineHemiptera, Odonata, and Ephemeroptera . Order Coleoptera consist of 20 species newlinecomprising of 5 families. Diptera with 3 genera comprising of 2 families, Hemiptera newlinerecorded with 13 species comprising of 7 families, Odonata with 8 species comprising newlineof 3 families and Ephemeroptera with 2 genera comprising of 1 family . Coleoptera newlinewere recorded in highest number followed by Hemiptera, Odonata, Diptera and newlineEphemeroptera respectively. The order Coleoptera composed of 44%, Diptera newlinecomposed of 7%, Hemiptera composed of 29%, Odonata composed of 16% and newline3 newlineEphemeroptera composed of 4% each of the total recorded aquatic insects species. This newlinesuggests that the Beel is rich in aquatic insects diversity. newlineDifferent Physico chemical parameters of water such as Temperature, newlinepH, Conductivity, Dissolved Oxygen, BOD, COD, Total Alkalinity, calcium ,Turbidity, newlineMagnesium , Hardness Sulphate and Free CO2 were analysed during the study period newlineand most of the parameters were correlated with the diversity of aquatic insects. newlineThe Study on the macrophytes diversity of the Beel revealed 37 newlinespecies. Out of theses 37 species, 19 species of macrophytes were utilized as habitat by newlineaquatic insects. Insects were found associated with different parts of the macrophyte newlinesuch as roots, stem and both sides of the leaves and carried out various activities. The newlineutilization of various parts of the macrophytes by insect involve foraging and feeding, newlineobtaining shelter , hiding from predators and for the purposes of breeding. newlineThe study revealed that Kapla Beel harbours diverse insect and newlinemacrophyte species. The Beel water seems favourable for aquatic insect community. newlineThe macrophytes are providing adequate support for assemblage of aquatic insects in newlinethe Beel. newlineKey words: Kapla Beel, Aquatic Insect ,Insect Diversity, Habitat utilization, newlineMacrophytes newline************ newline