Orientation of a hemipteran predator to vibrations produced by feeding caterpillars

Observations of search behavior in the predatory stinkbugPodisus maculiventris (Say) suggested that vibrations produced by prey as they chew on leaves may be an important cue used by this predator to locate prey. To test this hypothesis, studies were conducted to determine ifP. maculiventris search and make directional choices in response to vibrational stimuli produced by feeding green cloverworms,Plathypena scabra (F.), and to recordings of chewing vibrations. Modified soybean plants [Glycine max (L.)] were used in Y-choice tests. Individuals exposed to vibrational signals finished trials significantly more often on branches through which vibrations entered the plants than on no-stimulus branches. Also, a significantly higher proportion of individuals that initially moved onto branches with no stimulus reversed course than did those moving up branches with vibrational stimuli. The response ofP. maculiventris individuals to vibrational signals produced by a common prey species demonstrates that these predators are capable of using substrate-borne vibrations as cues for prey location.