The demographic and life table studies of Corcyra cephalonica on different food grains and their impact on population growth parameters and life history traits of indigenous Trichogramma chilonis and T. achaeae

The biological fitness of Trichogramma spp. is closely linked to the nutritional profile of host eggs, which depends on the food grains used to rear the factitious host Corcyra cephalonica (Stainton). Optimizing host diet is therefore critical for efficient mass production of high-quality parasitoids. Therefore, this study investigated the influence of four different food grains on the reproductive fitness and demographic parameters of C. cephalonica and assessed the subsequent impact of these host eggs on the growth parameters and life-history traits of Trichogramma chilonis Ishii and Trichogramma achaeae Nagaraja and Nagarkatti. C. cephalonica developed successfully on all tested food grains, with sorghum supporting the fastest development, highest fecundity and enhanced growth parameters. Both Trichogramma spp. emerging from sorghum-reared C. cephalonica eggs exhibited significantly shorter development and total pre-oviposition periods. While fecundity and ovipositional periods of both parasitoids showed no significant variation, key demographic parameters including, net reproductive rate, intrinsic rate of increase and finite rate of increase were highest and mean generation time and doubling time were lowest on sorghum-reared eggs, followed by maize-reared eggs. In conclusion, sorghum and maize proved to be most optimal substrates for mass-rearing C. cephalonica, producing high-quality eggs for efficient production of Trichogramma spp.