Effects of an extracted lectin from Citrullus colocynthis L. (Cucurbitaceae) on survival, digestion and energy reserves of Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae).

Lectins are the heterogeneous proteins in plants that serve as storage proteins via defensive mechanisms against herbivores. In the current study, a lectin was extracted and purified from seeds of Citrullus colocynthis by Sepharose 4B-Galactose and DEAE-cellulose fast flow chromatographies. Different concentrations of the lectin were added to artificial diet of Ectomyelois ceratoniae larvae finding out its effect on some biological parameters, digestive physiology and amount of storage macromolecules. It was found that CCA (C. colocynthis Agglutinin) increased life span from 23.44 days in control to 28.59 days in the treated individuals. Survival of larvae on control and CCA diets were 93.3 and 66.6%, respectively. Different concentrations of CCA significantly affected α-amylase and general proteolytic activities except for TAG-lipase activity. Activities of all specific proteases decreased when larvae were fed on different concentrations of CCA except for aminopeptidase. Meanwhile, amount of storage macromolecules in the larvae fed on different concentrations of CCA statistically decreased vs. control. These results demonstrated that CCA could intervene in physiology of E. ceratoniae and survival of larvae. Therefore, it can be taken into consideration in IPM of the pest through plant breeding programs.