Functional Response of Rhynocoris fuscipes (Fabricius) (Hemiptera: Reduviidae) to Teak Skeletonizer Eutectona machaeralis Walker (Lepidoptera: Pyralidae)

The Harpactorine reduviid Rhynocoris fuscipes (Fabricius) exhibited type II Holling's curvilinear functional response to teak skeletonizer Eutectona machaeralis Walker. The predator's attack rate increased as the prey density was increased. The maximum predations represented by 'k' values were 5.67 and 4.67 for female and male predators, respectively. But the highest attack ratios (y/x) (2.53 and 2.36 for female and male predators) were obtained at 1 prey/predator density and the lowest attack ratios (0.70 and 0.58 for female and male predators) at 8 prey/predator density. Positive correlations were obtained between the prey density and the prey killed for both female and male predators. But negative correlations were obtained between the prey density and searching time for both female and male predators. At high prey density, the predators spent less time in searching, therefore spent more time in handling, whereas at low prey density it was found reverse. However, handling time varied due to factors such as rate of pursuit of predator and prey escape or prey capture success.