Evidence of horizontal transmission of Ccep in rice moths parasitized by and its persistence across generations.

The horizontal transmission of endosymbionts between hosts and parasitoids plays a crucial role in biological control, yet its mechanisms remain poorly understood. This study investigates the dynamics of horizontal transfer of (Ccep) from the rice moth, , to its parasitoid, . Through PCR detection and phylogenetic analysis, we demonstrated the presence of identical Ccep strains in both host and parasitoid populations, providing evidence for natural horizontal transmission. To investigate thoroughly, -free colonies were acquired through tetracycline treatment, and the initial density of Ccep in host eggs significantly influences transmission efficiency. High-density Ccep infections led to rapid transmission, with F1 parasitoid titers increasing by as much as 100-fold, while low-density infections exhibited more gradual increases. Additionally, without continuous exposure to infected hosts, Ccep density in diminished over generations. These findings enhance our understanding of 's transfer dynamics and have important implications for developing effective and sustainable biological control strategies using parasitoid wasps, particularly in managing -related pest populations in agricultural systems.