Abnormal Morphological Development of Drosophilia melanogaster Compound Eyes Induced by Azadirachtin

The morphological characters of compound eyes dysplasia in Drosophilia melanogaster induced by azadirachtin was investigated. Flies were allowed to lay eggs on food mixture with 2 mg/kg of azadirachtin on which the resultant larvae and adults were fed and sampled for observation at different developmental stages. The images of stereo microscope and scanning electron microscope showed that adult eyes treated with 2 mg/kg of azadirachtin became smaller in size, irregular in ommatidia organization, rough on surface, duplicated, bent and forked in interommatidial bristles. The ultrastructure of compound eyes was characterized by transmission electron microscope. Results showed that chromatin condensation, phagocytic vacuole increase, nuclear membrane shrinkage, boundary fuzziness occurred in eye cells at the late third instar larvae, and they also showed that photoreceptors loss in different degrees at pupae and new adults. These results suggested that azadirachtin could induce abnormal morphological development in D. melanogaster compound eyes, which may gain a new insight into novel insect growth regulators.