Apidaecin 1A is a proline-rich antimicrobial peptide (AMP) found in honeybees (Apis mellifera) and is a key component of the insect innate immune system. It belongs to the apidaecin family of small, cationic peptides that are synthesized in the fat body and secreted into the hemolymph in response to bacterial infection, particularly Gram-negative bacteria. Unlike many antimicrobial peptides that disrupt bacterial membranes, Apidaecin 1A enters bacterial cells and inhibits intracellular targets, including components of the protein synthesis machinery, thereby blocking translation and leading to bacterial death. Its activity is highly selective for prokaryotic cells, minimizing toxicity to host tissues. Expression of Apidaecin 1A is regulated by immune signaling pathways such as the Imd pathway, which is activated by microbial recognition. In apicultural and entomological research, Apidaecin 1A is studied for its role in honeybee disease resistance, including defense against bacterial pathogens such as Paenibacillus larvae (the causative agent of American foulbrood), as well as for its potential applications as a template for novel antimicrobial therapeutics due to its stability, specificity, and mechanism of action.