The Chemical Ecology of a Generalist Predator: Decoding Volatile Cues in the Foraging Behavior of Chrysoperla carnea

Abstract

Volatile cues can influence prey location and habitat selection by generalist predators. This study evaluated the electrophysiological and behavioural responses of adult male and female Chrysoperla carnea to selected organic volatile compounds (OVCs). Laboratory-reared adults were examined using electroantennogram recordings and an eight-arm olfactometer. Nine OVCs were assessed electrophysiologically, and seven were evaluated for behavioural attraction against a hexane control. Antennal responses varied with dose and sex, with the highest amplitudes recorded at the 1% dose. In females, (E)-β-farnesene produced the strongest response (2.03 ± 0.04 mV), followed by (-)-β-caryophyllene (1.86 ± 0.09 mV) and (-)-trans-caryophyllene (1.75 ± 0.05 mV). In males, the strongest responses were elicited by (E)-β-farnesene (2.68 ± 0.32 mV) and allyl isothiocyanate (2.14 ± 0.20 mV). Olfactometer responses to all tested OVCs were significantly higher than the control. The greatest attraction was recorded for (-)-β-caryophyllene (20.00 ± 2.46%), methyl salicylate (18.30 ± 1.81%), and cis-3-hexenyl acetate (13.30 ± 2.01%). The findings indicate that adult C. carnea can detect and orient towards several plant- and prey-associated volatiles, although antennal sensitivity did not consistently correspond with behavioural attraction. The integrated approach distinguished physiological sensitivity from realised odour choice and provided a clearer assessment of biologically active cues. These compounds may have potential for semiochemical-based biological control, but their effectiveness requires validation under semi-field and field conditions.