Effects of Citrullus colocynthis agglutinin on intermediary metabolism of Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae)

Abstract In the current study, we examined the effects of Citrullus colocynthis agglutinin (CCA) on the intermediary metabolism of Ectomyelois ceratoniae larvae as a means of determining effectiveness of the lectin in pest control. Larvae were fed on control diets and diets containing CCA (2%) for 24 and 48 h. The activities of digestive α-amylase and general proteases significantly decreased in the larvae fed on the CCA diet, but no statistically significant changes were found in the case of TAG-lipase. Meanwhile, the activities of all specific proteases, except aminopeptidase, changed in the treated larvae for all time intervals. The activity of alanine aminotransferase significantly decreased in the treated larvae but the activities of aspartate aminotransferase and γ-glutamyl transferase increased 24 h post-feeding on the CCA diet. The activity of aldolase decreased 48 h post-feeding but lactate dehydrogenase (LDH) showed inverse results at the same time interval. The activities of acid phosphatase (ACP) and alkaline phosphatase (ALP) decreased 48 h post-feeding for ACP and at both time intervals for ALP. The amount of high-density lipoprotein (HDL) showed no statistical differences between control and CCA-fed larvae, but the amount of low-density lipoprotein (LDL) significantly increased in the CCA-fed larvae at both time intervals. The amount of protein increased in the larvae fed on the CCA diet, but the amounts of glycogen and triacylglycerol significantly decreased at both time intervals. Results of the current study clearly reveal that ingestion of CCA significantly influences the activities of digestive enzymes and disrupts the intermediary metabolism of E. ceratoniae larvae. Further studies on genetic engineering of CCA to provide resistant varieties might open a new avenue for safe and efficient control of the pest.