Ecology of slugs in Manitoba, and accumulation, storage and excretion of DDT in their bodies

Abstract

The purpose of this study was to observe different aspects of slug ecology in Manitoba, and examine the accumulation, storage and excretion of DDT by slugs. Reference was made to the culture of slugs for use in long-term laboratory experimentation. A field survey was done in August 1972 with samples of slugs being collected from 19 rural communities and urban areas in the southern part of the province. Three species of slugs are found in Manitoba at present. Agriolimax laeve occurred in nearly all areas sampled, whereas Lehmannia valentiana was found only in 2 greenhouses. Agriolimax reticulatus was found in all but 9 of the sampled areas. This species is responsible for much of economic and asthetic damage done by slugs in Manitoba. Severe climatic conditions during the summer and winter prevent slugs such as Lehmannia valentiana from becoming established in the field. Severe winter conditions likewise limit Agriolimax reticulatus to winter survival in the egg stage. Particular reference was made with respect to accumulation, storage and excretion of DDT. 14C-pp-DDT was fed to slugs at 4, 16, 40 and 80 ppm. dry weight in the diet. A variety of food sources were tested as vehicles for administering the DDT to the slugs and were exposed to the slugs for up to 104 days... The possibility of these ubiquitous invertebrates acting as indicators of pesticides in the soil environment was also considered. It is hoped that this study will act as a introduction to the study of terrestrial molluscs in Manitoba.