Significance Plants respond to biotic attack using an immune system of receptors to recognize molecules associated with danger. We identified an immune receptor, termed inceptin receptor (INR), able to confer responses to defined inceptin peptide fragments present in caterpillar oral secretions. Like many plant immune receptors, INR is encoded only by certain plant species but can be transferred across families to confer new signaling and defense functions. While INR is only found in the genomes of cowpea, common bean, and related legumes, it confers defined elicitor responses to transgenic tobacco and suppresses the growth of attacking beet armyworm larvae. INR expands the breadth of plant pattern recognition receptors to detection of chewing insect herbivores.