Protocols for Efficient Rearing and Functional Analysis of the Endoparasitoid Wasp Asobara japonica and its Host...

Parasitism is a biological interaction in which one organism exploits the body or resources of another (the host), resulting in substantial damage or death to the host. Among parasitic animals, parasitoid wasps are one of the most species-rich lineages, accounting for nearly 20% of all insect species. In particular, endoparasitoid wasps oviposit directly into host bodies and deploy a diverse array of venom factors to manipulate host development, immunity, and physiology. In response to wasp attack, hosts attempt to eliminate parasitoid eggs through innate immune mechanisms. However, the molecular and cellular mechanisms by which individual venom components modulate host biology and promote successful parasitism remain poorly understood. Here, we describe a standardized laboratory protocol for rearing the endoparasitoid wasp Asobara japonica and its host Drosophila melanogaster. Both parthenogenetic and sexual strains of A. japonica are available, and the parthenogenetic strain exhibits a high parasitism success rate, allowing stable maintenance of laboratory stocks for genome analysis and parasitism assays. A single-oviposition infection assay and a double-stranded RNA-based gene knockdown method were optimized for functional analysis of venom genes. Together, these protocols provide a practical experimental framework for dissecting the molecular mechanisms underlying parasitoid-host interactions and will facilitate future research in developmental biology, immunology, and physiology.