Species-specific detection of predation by coleoptera on the milacid slug Tandonia budapestensis (Mollusca: Pulmonata)

Abstract

Tandonia budapestensis is one of the most damaging species of slug in the UK, and can cause major losses in potatoes and cereals. No previous attempts appear to have been made to investigate the potential of natural enemies to control this slug. Monoclonal antibodies can be used to analyze the crop contents of predators collected from the field, in order to detect and quantify the remains of major pest species and identify important natural enemies. A species-specific antibody was therefore raised that could distinguish between T. budapestensis and all other molluscs tested. The antibody could detect as little as 5.57 ng of prey protein in an enzyme-linked immunosorbent assay. It could clearly identify the remains of T. budapestensis among the crop contents of the carabid Pterostichus melanarius for more than 26 h at 16°C, while the half-life of the antigen within the predator was 12.8 h. Such intervals make it a highly suitable antibody probe for quantifying predation during the previous day. The only serious cross-reactivity problem was with earthworms. The antibody can now be used to test predators collected from the field to see if they are indeed consuming this slug, or whether, as suggested by feeding trials, adult T. budapestensis are to some degree toxic to beetles and therefore avoided.