Acromyrmex octospinosus is the only Attine species present in Guadeloupe. It is an important phytophagous pest of food crops. In prospect of a selection of resistant cultivars, we have undertaken the study of some Dioscoreaceae forsaken by the leaf cutting ant during the selection of plant material to cut out. Biochemical and ethological investigations arc undertaken to determine the causes of this Attine inapperence to these plants. This natural resistance is of chemical kind and the cansing marcers are extractible with methanol. The preliminary analysis in thin layer chromatography allows linking them up 10 the saponin group. This point seems to be confirmed by the saponin quantitative analysis in the five studied Dioscoreaceae species.