Apidaecin IB was isolated from the honeybee Apis mellifera.  As a cationic proline-rich antimicrobial peptide (PrAMP), Apidaecin IB shows sequence homology with drosocin but is devoid of any pore-forming activity. Apidaecin IB is most active against gram-negative bacteria, it can navigate the outer membrane to the periplasm and then to the cytoplasm. Apidaecin IB is a non-lytic AMP, the main target of its antimicrobial activity appears to be inhibition of the chaperone heat shock protein DnaK. Toxicity appears to be exclusively to bacteria and thus has been trialled as a treatment for systemic bacterial infections. Numerous analogues and derivatives are being investigated to establish Apidaecin IB’s mode of action and also to improve its functionality.