Preliminary results on antimicrobial activity of Rhynchophorous ferrugineus hemolymph

Rhynchophorus ferrugineus (Coleoptera: Curculionidae), known as the Red Palm Weevil (RPW) and accidentally introduced in the Mediterranean areas, is considered a quarantine pest for tree palms especially in the urban environment. In order to understand the relationship among potential pathogens and RPW several studies were carried out on RPW immune system. Here we report the results of a preliminary study undertaken to investigate the effect of naturally occurring antimicrobial activities present both in the cell free hemolymph and in hemocytes lysate supernatant of RPW. The hemolymph was extracted from the older larvae sampled from infested palm trees. The protein fractions were extracted from hemolymph and hemocyte lysate supernatant by acidic precipitation. Antimicrobial activity was tested against a group of medical, veterinary and entomo-pathogenic bacterial strains. The antimicrobial activity was evaluated by determining minimal inhibitory concentrations (MICs) against planktonic form of the isolates using a standard micro-method. Data from this research could be useful to help for screening selection of entomopathogenic as well to search potential antimicrobial peptides against human or veterinary pathogens from insect sources.