Disentangling nutritional and structural constraints in host use by Trichogramma ostriniae using an Antheraea pernyi...

Trichogramma ostriniae is an important egg parasitoid used for biological control of the Asian corn borer, Ostrinia furnacalis. However, its large-scale application has been constrained by the lack of a cost-effective mass-rearing system. Eggs of Antheraea pernyi are widely used for industrial production of Trichogramma dendrolimi. However, T. ostriniae fails to emerge successfully from A. pernyi eggs, and the mechanisms underlying this host incompatibility remain unclear. In this study, we tested whether this limitation is caused by the physical barrier of the chorion or by nutritional incompatibility.

An artificial egg system was developed using A. pernyi egg liquid as the nutritional medium enclosed within a soft and penetrable membrane, thereby separating nutritional effects from chorionic constraints. T. ostriniae completed its entire development successfully in the artificial eggs. Compared with individuals reared on the conventional factitious host Corcyra cephalonica, adults reared in the artificial system were 21.4% larger and showed 24.9% higher fecundity. In addition, their parasitic capacity increased by 45.1%, whereas emergence rate and sex ratio did not differ significantly between the two rearing systems.

These results provide direct evidence that the contents of A. pernyi eggs are nutritionally suitable for the development of T. ostriniae, and that the chorion is the primary factor preventing successful natural parasitism. By overcoming this physical barrier, the artificial egg system offers a robust, low-cost and scalable approach for mass production of high-quality T. ostriniae, with strong potential to improve biological control programs against O. furnacalis and support sustainable pest management. © 2026 Society of Chemical Industry.