Comparative Biology of Callosobruchus maculatus and C. chinensis on Stored Cowpea and Lentil Seeds

Abstract

Comparative biological performance of Callosobruchus maculatus and Callosobruchus chinensis was evaluated on stored cowpea (Vigna unguiculata) and lentil (Lens culinaris) seeds to determine host suitability and pest fitness under storage conditions. Laboratory cultures were established under controlled temperature and relative humidity, and key life-history parameters including developmental duration, fecundity, adult longevity, and seed weight loss were recorded. Results demonstrated significant host-associated differences in biological performance between the two species. C. maculatus exhibited higher reproductive output and shorter developmental time on cowpea, indicating strong adaptation to this host, whereas C. chinensis showed comparatively better performance on lentil seeds. Cowpea supported greater infestation intensity overall, reflected in higher oviposition rates, larval survival, and adult emergence. In contrast, lentil seeds imposed moderate developmental constraints, reducing reproductive efficiency in both species. Inter-specific comparison revealed that C. maculatus was generally more aggressive and destructive under storage conditions, leading to greater quantitative and qualitative seed losses. Environmental stability within storage conditions further enhanced population buildup across generations, highlighting the risk of rapid infestation expansion. The study underscores host preference and biological specialization as key factors governing bruchid population dynamics in stored legumes. These findings provide critical insights for developing targeted post-harvest protection strategies, including host-specific resistance deployment and improved storage management practices to minimize bruchid-induced losses in pulse crops.