Journal of Environmental Biology

Temperature dependent mortality and behavioral changes in

a freshwater mussel Lamellidens marginalis to dimethoate

exposure

Saurabh Kumar1, Rakesh Kumar Pandey2, Shobha Das1?and Vijai Krishna Das2*

1Department of Zoology, Ganpat Sahai P.G. College, Sultanpur-228 001, India

2Kamla Nehru Institute of Physical and Social Sciences, Sultanpur- 228 118, India

*Corresponding Author email : dasvkster@yahoo.com

 Publication Data

Paper received:

22 September 2011

Revised received:

17 December 2011

Accepted:

19 March 2012

Abstract

Temperature is a crucial determinant of biogeography, directly affecting the behavioral responses of the organisms. An acute static bioassay was conducted to evaluate the effect of temperature on dimethoate toxicity in a freshwater mussel Lamellidens marginalis. The mussel, were exposed for 96 hr at different concentrations of dimethoate (155.00, 160.00, 165.00, 170.00, 175.00, 180.00, 185.00, 190.00, 195.00, and 200.00 mgl^-1) in the month of January when water temperature was 14.9?1.2⁰C and at concentration 35.00, 37.00, 39.00, 41.00, 43.00, 45.00, 47.00, and 49.00 mgl^-1?in the month of August when the water temperature was 28.0?0.5⁰C. The LC₅₀?values were calculated from the mortality data obtained (using EPA-Probit analysis version 1.5, statistical software). The 96 hr LC₅₀?value recorded at higher temperature was 36.34mgl^-1?and at low temperature was 163.59 mgl^-1. The mussel exposed at higher temperature showed more sensitive behavioral responses like huge mucus secretion, sudden closure of shell valves, quick post-mortem changes and increased oxygen consumption in comparison to exposure at low temperature. Therefore, the increasing threat of global warming increases the risk of pesticide toxicity in the exposed organisms.

Key words

Lamellidens marginalis, Dimethoate toxicity, Behavioral changes, Mortality 

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