Abstract:  【Aim】 The objective of this research is to clarify the preference and adaptability of the generalist parasitoid Spalangia endius to different types of novel hosts. 【Methods】 We selected S. endius adults reared on the pupae of Zeugodacus cucurbitae, Z. tau and Musca domestica, respectively, and compared their selective behavior, parasitization preference and adaptability to the other two non-rearing hosts from the above three hosts. 【Results】 S. endius adults reared on Z. cucurbitae pupae preferred to select and parasitize Z. tau pupae over M. domestica pupae, producing more offspring on Z. tau pupae. Similarly, S. endius adults reared on Z. tau pupae tended to select and parasitize Z. cucurbitae pupae, producing more offspring as well. However, no significant difference was found in the number of the selected hosts, parasitism rate and number of offspring in choice and no-choice experiments when S. endius adults reared on M. domestica pupae were transferred to Z. cucurbitae and Z. tau pupae. In addition, S. endius adults reared on the pupae of Z. cucurbitae and Z. tau more easily adapted to the pupae of Z. tau and Z. cucurbitae, respectively. 【Conclusion】 Based on the niche relationship of the three fly species, it is inferred that S. endius has higher fitness to a new host that has an overlapping niche with its rearing host.

Key words: Spalangia endius; Zeugodacus cucurbitae; Z. tau; Musca domestica, parasitic wasp, host adaptability, parasitism