The role of alkaloids in the feeding behaviour of slugs (Gastropoda: Stylommatophora) as pests of narrow-leafed lupin plants

Abstract

ABSTRACTThe degree of damage done to lupin plants by slugs is highly dependent on the species and the cultivar of plant. A study was carried out, in laboratory conditions and on small plots, to investigate the extent of damage done to plants of eight cultivars of narrow-leafed lupin when exposed to grazing by Arion vulgaris, Arion rufus and Deroceras reticulatum. Five sweet and three bitter cultivars of lupin were selected, respectively, having low- and high-alkaloid content. The contents of the dominant lupine alkaloids in these plants were determined. It was found that the susceptibility of the plants to slug damage is dependent on their content of alkaloids. The plants of high-alkaloid cultivars (Karo, Mirela and Oskar) were less heavily damaged by the studied species of slugs. The greatest differences were recorded for A. vulgaris and D. reticulatum, while the differences for A. rufus were smaller. For all studied slug species, the differences were statistically significant. The results of carried out experiments may potentially be of use in the selection of cultivars of Lupinus angustifolius to be grown in areas inhabited by these slug species.