Host cultivar drives sex-specific physiological adaptations in digestive performance, redox balance, and energy allocation of Plodia interpunctella

The Indian meal moth, Plodia interpunctella , is a cosmopolitan pest of stored commodities worldwide, causing substantial postharvest losses in date fruits. However, the physiological mechanisms underlying cultivar-dependent resistance and their sex-specific responses remain poorly understood. This study evaluated the influence of seven date palm cultivars, four dry (Zahedi, Deyri, Tori, Daglatnour) and three semi-dry (Estamaran, Khasouee, Pyaram), on digestive enzyme activities, metabolic profiles, energy reserves, oxidative stress biomarkers, and sex-dependent variations in larval stages. Larvae reared on dry cultivars, particularly Daglatnour and Zahedi, exhibited significantly higher activities of digestive enzymes (total protease and α-amylase) and aminotransferases (ALT, AST, and γ-GT), along with greater accumulation of protein and triacylglyceride reserves, indicating superior nutritional quality and efficient nutrient assimilation. In contrast, semi-dry varieties (Estamaran, Khasouee, and Pyaram) induced marked increases in aldolase activity, lactate production, and oxidative stress biomarkers (MDA and RSSR/RSH ratio), indicative of metabolic impairment, enhanced glycolytic flux, and compromised redox homeostasis. Hierarchical clustering based on all biochemical parameters clearly segregated cultivars into two major clusters corresponding to dry and semi-dry categories, confirming that fruit moisture content serves as a reliable proxy for nutritional quality and resistance potential. Notably, female larvae consistently exhibited higher enzymatic activities and greater macromolecular content than males across all cultivars, revealing sex-specific metabolic adaptations driven by the elevated energetic demands of oogenesis. Collectively, these findings establish that cultivar-dependent nutritional variability critically modulates digestive physiology, redox balance, and energy metabolism in P. interpunctella , with dry cultivars providing superior nutritive support relative to semi-dry ones. These results provide essential baseline data for integrating host plant resistance into integrated pest management (IPM) programs, offering a sustainable, non-chemical strategy for postharvest protection of dates.