Azadirachtin-induced effects on various life history traits and cellular immune reactions of Galleria mellonella (Lepidoptera: Pyralidae)

Abstract

The effects of the botanical insecticide azadirachtin were examined on the life history traits, fecundity and immune parameters of Galleria mellonella L. (Lepidoptera: Pyralidae). We determined that for the topical application of azadirachtin, the LC50 was 16.564 ppm; at 100 ppm the adult emergence time was prolonged, however the longevity of adults remained unchanged above sublethal concentrations. The mean number of healthy eggs and the fecundity of adults decreased, whereas the number of defective eggs increased with azadirachtin treatment. At concentrations >50 ppm female G. mellonella adults laid no eggs. Azadirachtin reduced total hemocyte counts at 24 and 48 h posttreatment, however the alterations in differential hemocyte counts were only significant at 100 ppm. Laminarin-induced nodulation response and the spreading ability of hemocytes were also suppressed with azadirachtin treatment. Our results suggest that azadirachtin, as a good candidate for integrated pest control, has the capability to affect the biological parameters and cellular immunity of the model insect G. mellonella.

Keywords

• Galleria mellonella
• azadirachtin
• fecundity
• hemocyte count
• nodule