Formaecin family of antimicrobial peptides isolated from the bulldog ant Myrmecia gulosa in response to bacterial infection. Formaecins are inducible peptide antibiotics and are active against growing Escherichia coli but were inactive against other Gram-negative and Gram-positive bacteria. Formaecin peptides are 16 amino acids long, are rich in proline and have N-acetylgalactosamine O-linked to a conserved threonine [PMID: 9497332].