Economics trumps biology: Corcyra cephalonica as the optimal factitious host for cost‐effective mass production of Chelonus bifoveolatus, a key parasitoid of Spodoptera frugiperda

The parasitoid Chelonus bifoveolatus is a promising biocontrol agent against the invasive fall armyworm (FAW) Spodoptera frugiperda, but its practical application hinges on cost-effective mass rearing. This study compares the biological performance and production economics of Ch. bifoveolatus reared on two factitious hosts (Corcyra cephalonica and Spodoptera litura) under controlled laboratory conditions. Our results showed that Ch. bifoveolatus reared on S. litura had higher parasitism rates (86.63% versus 70.88%), an increased female offspring proportion (47.90% versus 32.08%), shorter developmental time (33.22 versus 69.72 days), longer female adult longevity (29.16 versus 17.73 days), and larger parasitoid body size than those reared on C. cephalonica. The pupation rate of Ch. bifoveolatus was higher when reared on C. cephalonica than on S. litura, but the emergence rate of Ch. bifoveolatus was similar between those reared on C. cephalonica and S. litura. The production costs for 100 parasitoid individuals were strikingly lower for C. cephalonica, representing 1.78- and 11.38-fold reductions compared with S. litura and FAW, respectively. The production efficiency of Ch. bifoveolatus using the factitious host C. cephalonica (20,400 individuals) exhibited a 44% increase in overall parasitoid yield relative to S. litura (13,600 individuals), and a 91% increase compared with cultivation on FAW (10,400 individuals). Despite some trade-offs in parasitoid fitness, rearing Ch. bifoveolatus on C. cephalonica offers substantial cost savings compared with rearing on Spodoptera hosts. These findings support the use of C. cephalonica as a practical, scalable host for augmentative biological control programs targeting FAW, balancing the economic feasibility without sacrificing significant field performance.