Host discrimination in Dinocampus coccinellae (Hymenoptera : Braconidae), a solitary parasitoid of coccinellid beetles

The ability of a solitary parasitoid, Dinocampus coccinellae (Schrank) to d iscriminate between a parasitized and unparasitized host, Coccinella septem punctata I,. (Coleoptera: Coccinellidae) was tested in the laboratory. A D. coccinellae female wasp was placed together with a host beetle and allowed to parasitize 3 successive times, and the time interval between these para sitizations was measured. The wasp successfully parasitized the host within 25 a on average and avoided superparasitism for 155 s after the Ist parasi tization. The period of rejection between the 2nd and 3rd parasitization fu rther extended to about 4 min. Furthermore, the behavioral pattern of a par asitoid wasp and 3 host beetles monitored by a video camera confirmed the h ost discrimination of D. coccinellae. The wasp was unable to discriminate a host recently parasitized by her genetically identical sister. A possible reason for weak host discrimination of D. coccinellae is discussed.