Disclosed are novel insecticidal polypeptides, and compositions comprising these polypeptides, peptide fragments thereof, and antibodies specific therefor. Also disclosed are vectors, transformed host cells, and transgenic plants that contain nucleic acid segments that encode the disclosed .delta.-endotoxin polypeptides. Also disclosed are methods of identifying related polypeptides and polynucleotides, methods of making and using transgenic cells comprising these polynucleotide sequences, as well as methods for controlling an insect population, such as Colorado potato beetle, southern corn rootworm and western corn rootworm, and for conferring to a plant resistance to a target insect species.