Antimicrobial activity of external secretions produced by red palm weevils

External secretions play a vital role in external immune defense. However, the functions of these exudates are largely unknown in the red palm weevil, <i>Rhynchophorus ferrugineus</i> (Olivier) (Coleoptera: Curculionidae). In order to determine their role in external immunity, the immunosuppressive efficacy of the secretions <i>in vitro</i> against microbes, including bacteria and fungi, was clarified. In the present study, we found that these secretions had antimicrobial activity <i>in vitro</i>, implying external immunizing potency against pathogens. Surprisingly, all liquid phases of secretions could not significantly inhibit the growth of microbes <i>in vitro</i> compared to solid phases.