The results of the present study recommended A. niger (Gb) as a non-pathogenic strain. However A. niger
strain IMI60286 caused significant larval death. This difference in the pathogenicity of two strains of the
same species may be due to differences in the capacity of mycotoxins production. Revees and colleagues [21]
identified an environmental isolate of A. niger for the production of gliotoxin, a fungal metabolite known as
an immuno-suppressive agent which might have caused death of the G. mellonella larvae. Another reason
which could explain the strain difference in pathogenicity could be the number of viable spores injected. Each
larvae infected with A. niger (Gb) received 11,000 viable spore while for the strain IMI60286 received 39,000
viable spores, almost four times higher than the inoculum size injected than A. niger (Gb). However, strain Gb
experiments should be repeated with different spore inocula sizes to investigate such strain differences. In
contrast, A. flavus (MMG) and A. terreus (MMG) were found to have the ability to kill moth larvae. To my
knowledge, three species of Aspergillus included in this survey, A. terreus, has not been studied previously for
pathogenicity using G. mellonella. As the strain of A. terreus used for this present study was a clinical isolate,
it is perhaps not unsurprising that it exhibited pathogenic characteristics in our present experiment.