EFFECT OF TWO ORGANOPHOSPHORUS PESTICIDES ON THE REPRODUCTIVE BIONOMICS OF FRESHWATER FAIRY SHRIMP STREPTOCEPHALUS DICHOTOMUS (BAIRD, 1860) (CRUSTACEA: ANOSTRACA)

Author(s): Arun Kumar MS* and A Jawahar Ali

Abstract

This study evaluates the effects of the two organophosphorus pesticides (malathion) and (glyphosate), on the reproductive bionomics of the freshwater fairy shrimp Streptocephalus dichotomus. The sublethal effects at 1/5th of 96 h LC50 of malathion, 2.0 ppm, and glyphosate, 0.0011 ppm on cyst production of the pre-adults were also studied. The 24 and 48 h LC50 values of malathion for nauplius were found to be 14 and 12 ppm; for glyphosate they were 0.026 and 0.014 ppm, respectively. The 24, 48, 72 and 96hr LC50 values of malathion for juveniles were 9.6, 8.0, 7.1 and 6.4 ppm; for pre-adults were 26.0, 16.8, 12.1and 9.1 ppm, respectively. Similarly the 24, 48, 72 and 96 hr LC50 values of glyphosate for juveniles were 0.097, 0.052, 0.032 and 0.017 ppm; for pre-adults were 0.013, 0.010, 0.007 and 0.005ppm, respectively. Animals treated with malathion (2.0 ppm) produced 41.2±12.7 cysts/female/day whereas the glyphosate exposure at 0.0011ppm resulted 95.5±12.6 cysts/female/day when compared to control (118.7±10.21cysts/female/day). An overall significant effect of pesticides on the cyst production between control and pesticide treated fairy shrimps was revealed (P<0.001). Of the two organophosphorus pesticides tested, glyphosate was found to be significantly more (1000 times) toxic to fairy shrimp nauplius, juveniles and preadults than malathion. However, at the sub lethal level, malathion showed higher reproductive toxicity than glyphosate.

Share this article

International Journal of Bioassays is a member of the Publishers International Linking Association, Inc. (PILA), CROSSREF and CROSSMARK (USA). Digital Object Identifier (DOI) will be assigned to all its published content.