Podoler, H., Dept. of Entomology, The Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot, Israel
Effects of variable temperatures on responses of Aphytis melinus and A. lingnanensis to host density
The effects of three variable temperature regimes (18-24, 24-29, and 29-35°C) on the responses of two species of the genus Aphytis Howard (Hymenoptera: Aphelinidae), parasitic upon the California red scale, were studied, and a test to analyze parasite behavior was developed. Aphytis lingnanensis Compere was generally more efficient than A. melinus DeBach; however, whereas a high temperature regime (29-35°C) had a negative effect on the responses of A. lingnanensis, it improved those of A. melinus. The two species distributed their eggs in clumps, but were able to respond to increasing host density by reducing the number of eggs laid per encounter. The combined effects of numerical, and functional responses of the two species on host population were considered, with special reference to the mechanism of competitive displacement. © 1981 Springer Science + Business Media B.V.
