Functional responses to prey density ofEphedrus cerasicola [Hym.: Aphidiidae], an aphidiid parasitoid ofMyzus persicae [Hom.: Aphididae]

The functional responses of the parasitoidEphedrus cerasicola Starý parasitizingMyzus persicae (Sulzer) on a paprika plant, were studied for single females at different host densities (1 to 120 aphids per 1.8 dm³) during 3 different time periods (1 hr, 6 hrs, 24 hrs) at 21 °C. The response during 1 hr was curvilinear and is described by the random parasite equation according toRogers (1972). A maximum of 5–6 aphids could be parasitized during 1 hr. After 6 hrs, the response was linear, although it showed a slight sigmoid trend. In the 24-hr experiment, the response was curvilinear, but due to high rate of parasitization together with superparasitism no curve was estimated. The area of discovery was calculated for all densities and exposure times and ranged from 0.15 to 0.79 (1 hr), 0.69 to 1.96 (6 hrs), and 0.81 to 3.21 (24 hrs).