Effects of Beauveria bassiana and Metarhizium anisopliae on cellular immunity and intermediary metabolism of Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae)
Keywords:Entomopathogenic fungus, Spodoptera littoralis, Immunity, Intermediary metabolism
In the current study, fifth larval instars of Spodoptera littoralis were injected by spores of Beauveria bassiana and Metarhizium anisopliae to find their effects on cellular immunity and enzymes involved in intermediary metabolism. The highest numbers of plasmatocytes were observed 6 hours post-injection for both entomopathogenic fungi although there were the slight significant differences between time intervals of 3-12 hours. The highest numbers of granulocytes were observed 6 hours post-injection for both fungi although slight statistical differences were found by injecting spores of B. bassiana after 3-6 hours. Injection of larvae by B. bassiana spores caused the highest number of nodules 12 hours postinjection but spores of M. anisopliae caused the highest number of nodules after 1-6 hours of postinjection. The highest activity of phenoloxidase was obtained 6-12 hours post-injection by B. bassiana spores while the highest enzymatic activity was found 12 hours after injection by M. anisopliae spores.
In case of assayed enzymes including, alanine aminotransferase, aspartate aminotransferase, δ-
glutamyl transferase, acid phosphatase, alkaline phosphatase and lactate dehydrogenase, the highest activities were observed 6-12 hours post-injection by fungal spores. The results demonstrated that the highest physiological phenomena like immune responses and intermediary metabolisms were occurred 12 hours post-injection by entomopathogenic fungi. Determination of these processes could be helpful to improve quality of entomopathogenic fungi and their efficiency to decrease population outbreaks of pests.