Arpita Dalal
Assam University, India
Title: Do aquatic insect change over time and space? A study from different lentic ecosystems of Cachar district, Assam, India
Biography
Biography: Arpita Dalal
Abstract
Aquatic insects are commonly known as good fish diet, bioindicators of freshwater pollution and can be utilised asbiocontrol agents. Understanding the drivers of insect distribution, abundance and species richness is thus vital for healthy fish stocks and aquaculture practices. The present study examined spatial and temporal variation in aquatic insect assemblages in several different lentic (standing freshwater) ecosystems- oxbow lake, Floodplain Lake, rural and urban ponds, and two agricultural fields of Cachar district, Assam. With kick sampling, aquatic insects were collected along with water samples in four seasons (post monsoon, winter, premonsoon and monsoon) during 2013-14. We collected2260 individuals belonging to 119 taxa,36 familiesand8 orders. The highest number oftaxa was recorded from the floodplain lake,with thelowest from the oxbow lake. Post monsoon and winter recorded highest taxa, whereas monsoon had the lowest. Engelmann’s scale of dominance showed Anisops breddini (Water boatman), Cloeon sp. (Mayfly), Micronectas cultellaris (Lesser water boatman), M. Haliploides (Lesser water boatman), and Ochthebius sp. (Minute moss beetle) as the eudominant taxa from the different lentic systems. There was a significant positive correlation ofbothtaxa richness and taxa density with dissolved oxygen and potassium, whereas there were negative correlations with water temperature, rainfall, water depth and size of water bodies. In addition, we discuss here the factors regulating the distribution of aquatic insects in different seasons.