The subject of this article is a search for the long-term immunological effects of alloferon and 3 structural analogues of alloferon,which were earlier characterized by the highest pro-apoptotic activity in Tenebrio molitor.The differences in the actions of these peptides on immune response were observed.Alloferon increased nodulation and significantly phenoloxidase activity in the hemolymph of experimentally infected T.molitor.However,[Phe(p-NH2)1]-and [Phe(p-OMe)1]-alloferon strongly inhibited cellular and humoral defense of the mealworm against Staphylococcus aureus infection.One day after injection of these peptides,the specific biochemical and morphological hallmarks of apoptosis in bacteria-challenged hemocytes were visible;in contrast,3 days after peptides injection in all hemocytes,caspase activation was not observed.However,these new,circulating hemocytes differed from the control and the peptide-untreated bacteria-challenged hemocytes.They had an increased adhesion that led to a separation of viable,anucleated fragments of hemocytes that retain the ability to adhere and to form long filopodia.The peptide-induced separation ofhemocyte fragments may resemble the formation ofplatelets in mammals and perhaps play a role in sealing wounds in insects.The results of in vivo studies may suggest a long half-life of studied peptides in the hemolymph of mealworm.Moreover,we showed the importance of the N-terminal histidine residues at position one of the alloferon molecule for its immunological properties in insects.The results obtained here show that alloferon plays pleiotropic functions in insects.