The carbohydrate ligands on the host embryo mediate intercellular migration of the parasitic wasp embryo

► We developed invasion blocking assay of wasp morula into host embryo. ► The assay revealed that N-linked carbohydrate chains with fucose residues is important for invasion. ► FITC-labeled AAA lectin that binding fucose was located host surface. ► Ca2+ ions dependency of invasion was also investigated. Invasive stage embryos of the parasitic wasp Copidosoma floridanum transmigrate through the epithelium of phylogenetically distant host embryos in a manner that is similar to mammalian leukocyte infiltration. Host embryonic cells appear to recognize the invading wasp embryo by components on the cell surface. We developed an in vitro wasp entry inhibition assay and found that C-type lectins of the wasp embryo bound to N-linked carbohydrate chains with fucose residues on the surface of host embryo. This is the first report showing a receptor–ligand interaction between heterologous multicellular organisms.