Haemolymph Phenoloxidase Activity of Larval Plodia Interpunctella and Galleria Mellonella in Response to Beauveria Bassiana and Pseudomonas Fluorescens

Phenoloxidase (PO) is an important component of immune system in invertebrates. In this study, PO activity was investigated in two pyralid species, Plodia interpunctella and Galleria mellonella treated with Beauveria bassiana and Pseudomonas fluorescens. PO activity was enhanced in response to two entomopathogens in both insects, but it was greater in P. interpunctella by almost two folds compared to G. mellonella. Furthermore, B. bassiana managed to induce the immune system two times faster than the Pseudomonas in Plodia. In contrast, Galleria PO activity response time was the same for both pathogens (12 h). Accordingly, it may be postulated that the induction of immune system- or its index genes, i.e., prophenoloxidase, are different in Galleria and Plodia caterpillars. In G. mellonella, the response was quite the same to both pathogens suggesting that the insects take similar routes to withstand the attack, while P. interpunctella immune system activation seems to respond by different pathways.