Changes in life history parameters and transcriptome profile of Serangium japonicum associated with feeding on natural prey (Bemisia tabaci) and alternate host (Corcyra cephalonica eggs)

Abstract

Background: The mass production of natural predators with prolonged shelf life is a prerequisite for their field application as pest control agents. The traditional methods used for the mass production of Serangium japonicum rely heavily on the consistent supply of natural prey. This study explains the effects of B. tabaci (natural prey) and C. cephalonica eggs (alternative food) on life history and transcriptome profile of S. japanicum. Methods: This study compares the effects of B. tabaci (natural prey) and C. cephalonica eggs (alternative food) on biology, reproduction, and predatory efficacy, and transcriptome profile of S. japanicum. Results: This study revealed that S. japonicum was able to successfully complete its life cycle while feeding on B. tabaci (natural prey) and C. cephalonica eggs (alternative food). The C. cephalonica eggs fed S. japonicum individuals had longer developmental period and lower fecundity as compared to those feeding on whitefly but the survival rates (3rd instar nymphs, 4th instar nymphs and pupae) and predatory efficacy of C. cephalonica eggs fed S. japonicum individuals were significantly similar to to those feeding on whitefly.Transcriptome analysis showed that when faced with dietary changes, S. japanicum could successfully feed on C. cephalonica eggs by regulating genes related to nutrient transport, metabolism, and detoxification. Moreover, S. japanicum degraded excess cellular components through ribosomal autophagy and apoptosis, which provided sufficient materials and energy for survival and basic metabolism. Conclusion: Corcyra cephalonica eggs can be used as an alternate host for the predator, Serangium japonicum, as the survival rates and predatory efficacy of the predator are similar to those feeding on the natural host (B.tabaci). When faced with dietary changes, S. japanicum could successfully feed on C. cephalonica eggs as revealed by upregulation of genes related to nutrient transport, metabolism, and detoxification. These findings are of great significance for studying the functional evolution of S. japonicum in response to dietary changes.