Aquatic Insects of Modi Khola River in PARBAT, Nepal
Date
2021
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Zoology
Abstract
Aquatic insects are those insects that spend some part of their lifecycle closely associated
with water, either living beneath the surface or skimming along on top of the water and
they are abundant in most freshwater habitat. In aquatic ecosystem they play vital role or
used as indicator of water. In this study, aquatic insects were collected from nine
sampling sites of river across different habitats (near to forest area, near to agricultural
field and near to human settle area). Each sampling site further divided into three
sampling points on the basis of river heterogeneity. Insect collection was done by
Sweeping method for littorial zone and D-Frame kick net for benthic zone by One minute
kick method, Sieving was used for sandy places of rivers and All out search method was
used in all possible substrata. The relation of aquatic insects with physical parameters was
showed by using Karl Pearson’s Correlation method. A total of 2,230 insects belonging to
48 genera under 33 families and eight orders including of two unidentified species were
recorded. During the study period the highest abundance of insect species was from order
Ephemeroptera of the total insects sampled. It was followed by Trichoprera, Diptera,
Plecoptera, Odonata, Megaloptera, Coleoptera and Hemiptera. Seasonally, abundance of
orders of insect was highly varied. The diversity index and species richness of the insects
were recorded higher in the pre monsoon in comparison to post monsoon. Analysis of
variance shows no significant relation between aquatic insects and seasons. Near to forest
area, diversity of insects was high followed by near to agricultural field and human settle
area. The number of aquatic insects shows positive relation with DO but negative relation
with temperature, velocity and CO
2
in both seasons. In pre monsoon, diversity shows
positive correlation with alkalinity and negative with pH.
Description
Keywords
Aquatic insects, River water, Ecological factor