none The oviposition behavior of Microctonus hyperodae Loan and M. aethiopoides Loan (Hymenoptera: Braconidae: Euphorinae) was observed in laboratory tests involving two host species, Listronotus bonariensis (Kuschel) and Irenimus aequalis Broun (both Coleoptera: Curculionidae). The parasitoids exhibited similar behaviors to one another and towards the two hosts, but M. aethiopoides attempted to oviposit more frequently and oviposited less successfully. About 66% of oviposition attempts occurred near the host's anus and 33% occurred near the mouth, of which 8% and 3%, respectively, were successful. On rare occasions, oviposition was attempted near a host's eye, antenna, leg or thorax, but such attempts always failed. Successful oviposition was characterized by insertion of the parasitoid ovipositor followed by tapping of the host with one or both antennae and, in the case of L. bonariensis, about 60s of host hyperactivity. Parasitoids were unable to oviposit in motionless hosts, but the hosts did not appear to exploit this as a means of defence. Microctonus hyperodae searched segments of ryegrass more often than M. aethiopoides, but neither species appeared attracted to host frass. Reproduction; Reproductive behaviour; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts Irenimus aequalis; Listronotus bonariensis (Curculionidae ); Hymenopteran parasites; Microctonus; Parasite oviposition behaviour Microctonus aethiopoides; Microctonus hyperodae (Braconidae ); Egg laying; Oviposition behaviour; Coleopteran hosts; Irenimus aequalis & Listronotus bonariensis