Orientation behaviour of the predatory hemipteran Perillus bioculatus to plant and prey odours

The pentatomid predator P. bioculatus responded by positive odour-condition ed anemotaxis when exposed to airborne volatiles emitted by potato plants d amaged by Colorado potato beetle larvae, whereas intact potato plants and n on-feeding larvae as odour sources failed to elicit anemotaxis. Walking tra cks of adult predators had higher values of straightness and upwind fixatio n when odours emanating from mechanically damaged plants were encountered t han tracks registered in response to air carrying volatiles from intact pla nts, but these parameters returned to control values within 1-2 h after dam age was caused. In contrast, air led over plants damaged by beetle larvae e licited orientation responses at least 3 hours after feeding damage ceased. The combination of chemical data on headspace composition, olfactory sensi tivity established in electro-antennogram studies and behavioural data pres ented here imply a role of sesquiterpenoid plant volatiles as odorous cues eliciting attraction of this predator to damaged potato plants.