Kr. Prabhat Ranjan* & M. Prasad
Dept. of Zoology, Ranchi University, Ranchi
Received 5th May, 2010; Revised 11th August, 2010
Abstract : Co-related with the seasonal fluctuations and sliding threshold of food resources, temporal and spatial variation in the benthic population of Dytiscidae larvae commonly called water tiger have been significantly recorded in perennial tropical pond of Belwatika Daltongan, Palamau, Jharkhand. The present work is restricted to the seasonal sampling and determination of abundance of the Dysticid larvae called water tigers during March -09 Feb. 10 from different points of the pond bed. Highest population (RA 44.44%) of water tigers have been found to occur in the months of Aug., Sept. & Oct. when the pond was having 12±2 feet central and 7±2 feet peripheral water column. Contrary to this the lowest population (RA 24.74%) was recorded in the months of May, June and July when the water columns were 7±2 feet central and 5±2 feet peripheral. The average density of the larvae (RA 33.88%) was recorded in the months of Nov.-Feb. The above temporal variation is also remarkably linked with the relative clustering of larvae in the peripheral pond-bed forming the spatial variation compared to the central bed where the chances of predation also decrease due to less availability of microbenthic invertebrates upon which the water tigers predate.
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