Effects Of Chemical Pesticides On The Gravid Females And Stadia Of The Woodlouse, Porcellio Scaber (Latreille) (Isopoda, Oniscidea)

Abstract

Studies were made on the mortality rates of the gravid females, and on the survival and growth rates of the stadia of the woodlouse Porcellio scaber (Latreille) exposed for a period of 21 days to sub-lethal concentrations of five different pesticides viz: abate, sumithion, pesguard (insecticides), benlate (fungicide) and gramaxon (herbicide). The survival of gravid females was severely affected when they were exposed to gramaxon or sumithion, but only marginally so following exposure to the other pesticides. Marked variation occurred in the number of broods liberated by females exposed to different pesticides. A'delay in liberating the young from the brood pouch by the females exposed to pesguard was noted. High mortality of the young born to the females exposed to gramaxon or sumithion was evident. A significant difference was observed in the rate of growth of stadia born and exposed from birth to different pesticides. The ecological implications of these findings are discussed.