A SPECIES-SPECIFIC MONOCLONAL-ANTIBODY SYSTEM FOR DETECTING THE REMAINS OF FIELD SLUGS, DEROCERAS-RETICULATUM (MULLER) (MOLLUSCA, PULMONATA), IN CARABID BEETLES (COLEOPTERA, CARABIDAE)

The field slug, Deroceras reticulatum (Muller), is probably the most d amaging and widespread species of slug, causing severe economic losses in a broad range of crops in temperature zones throughout the world. Investigations into the role of predation in the population dynamics o f this species required a biochemical system which was capable of iden tifying the remains of this slug in the crop contents of predators, an d distinguishing them from those of other molluscs. A monoclonal antib ody was developed (IgM isotype). This was capable of separating, in an enzyme-linked immunosorbent assay, D. reticulatum from the related D. caruanae (Pollonera) and all molluscs and other invertebrates tested, with the unexpected exceptions of New Zealand flatworms, Artioposthia triangulata (Deny) and the millipede Polymicrodon polydesmoides (Leac h). Characterization of the antibody and assay demonstrated that the s ystem could clearly detect as little as 11.6 ng of D. reticulatum prot ein in 200 mu l of buffer. Slug remains could be identified as such in the crops of the carabid predator Pterostichus melanarius Illiger for 38.1 h, while the antibody-antigen reaction declined to half of that measured immediately following consumption, after 12.9 h. A practical and highly sensitive system was therefore developed, using the first s pecies-specific monoclonal antibody available for the investigation of predation on slugs.