Bee Abaecin is an antimicrobial peptide produced primarily by the honeybee (Apis mellifera) as part of its innate immune system and plays a critical role in defense against bacterial infections. Abaecin is a proline-rich antimicrobial peptide that is induced through immune signaling pathways such as the Toll and Imd pathways following pathogen recognition. Unlike many membrane-disrupting antimicrobial peptides, Abaecin functions by entering bacterial cells and interfering with intracellular protein synthesis and other essential cellular processes, often acting synergistically with other bee antimicrobial peptides such as defensin-1, apidaecin, and hymenoptaecin. In honeybee health, Abaecin contributes to protection against bacterial pathogens including Paenibacillus larvae, the causative agent of American foulbrood, and Melissococcus plutonius, which causes European foulbrood. Expression of Abaecin is an important indicator of immune activation in bees and is frequently used as a biomarker in studies of pathogen infection, pesticide exposure, and colony stress. Characterization of Abaecin supports research into honeybee immunity, host–pathogen interactions, and strategies to improve colony resilience, which is essential for pollinator health, agricultural productivity, and ecosystem stability.