Predation Rate and Demographic Parameters of Cheilomenes sexmaculata (Coleoptera: Coccinellidae) on Aphis craccivora

Abstract

The ladybird beetle Cheilomenes sexmaculata is an effective generalist predator widely associated with suppression of aphid populations in leguminous agroecosystems. Laboratory studies were conducted to evaluate its predation rate and demographic parameters when feeding on Aphis craccivora under controlled environmental conditions. Different prey densities were provided to determine feeding efficiency, developmental performance, survival, fecundity, and population growth potential of the predator. Results indicated that both larval and adult stages actively preyed upon A. craccivora, with fourth instar larvae and adult females exhibiting the highest consumption rates. Predation increased with prey density up to a saturation point, beyond which handling time limited further consumption. The predator successfully completed its life cycle on aphid diet, demonstrating strong adaptability and high survival across developmental stages. Females exhibited greater longevity and higher fecundity compared with males, with peak egg laying occurring during the early reproductive period. Life table analysis revealed a positive intrinsic rate of increase, high net reproductive rate, and short generation time, indicating strong population growth potential under aphid-prey conditions. Survival curves showed gradual mortality across life stages, with higher survivorship in early instars. The demographic performance of C. sexmaculata suggests its suitability for biological control programs targeting A. craccivora in pulse and vegetable cropping systems. Continuous prey availability significantly enhanced reproductive output and predator establishment. The study highlights the predator’s strong functional and numerical responses to aphid density, reinforcing its role as an efficient natural enemy.