Cowpea (Vigna uniguiculata) suffers heavily from the cowpea weevil, Callosobruchus maculatus, either  crops, as well as under storage, and insecticides do not eliminate the infestation. Insect resistance in cowpea is being studied with inhibitors against the insect peptidases. In this work two inhibitors isolated from the seeds of different species of Bauhinia, BbKI (Bauhinia bauhinioides Kallikrein Inhibitor) and BrTI (Bauhinia rufa Trypsin Inhibitor), with 81 percent identity in their primary sequences, were investigated on insect development. The results showed that the emergency of the adult bruchid was affected by BrTI but not by BbKI. The major differences between those proteins are the presence of RGD and RGE motifs in BrTI molecule. To assess the contribution of these sequences on BrTI specificity, the amino acids residues around P21-28 in BbKI were replaced by those in present in BrTI (V/E21, S /A24, H/R25, H/D27 A/G28 and in region P127-130 (E/D127, Q/E130). A synthetic gene with codons preferential for E. coli was constructed codifying chimeric BbKI protein. The RGD/RGE sequence was shown to be essential for BrTI activity on insect development since BbKI itself does not affect insect survival, while rBbKIm strongly inhibits C. maculatus larvae development. With peptides YLEAPVARGDGGLA-NH₂ and YLEPVARGEGGLA-NH₂ the RGE sequence was shown to block the normal development of C. maculatus larvae, but not the RGD sequence. Furthermore, the peptide YLEPVRGEGGLA-NH₂ showed more effectiveness than the native protein. By confocal miscroscopy, rBbKIm-FITC was detected in the midgut, fat body and malpighian tubules, but not the peptide IVYYPDRGRE-NH₂-FITC. Supported by FAPESP, CNPq, and SPDM/FADA, Probal (CAPES/DAAD).