Impact of odor signals on Cycloneda sanguinea (Coleoptera: Coccinellidae) searching behavior

Abstract

Volatile infochemicals generated by aphids, their host plants, or from the interaction between host plant and herbivore (herbivore-induced volatile plant compounds) are among the environmental stimuli used by predators to locate prey. The objective of this study was to evaluate the olfactometric response of the predator Cycloneda sanguinea (Coleoptera: Coccinellidae) to volatile infochemicals associated with the tomato plant, Lycopersicon esculentum Mill. (Solanaceae), and the aphid prey Myzus persicae Sulzer (Hemiptera: Aphididae). Predator behavior was evaluated in an airflow olfactometer at 24 ± 2°C with 65 ± 10% relative humidity and a 16 h photoperiod. Latency time and the number of visits to the active chamber where the odor source was located were recorded. The odor sources studied were: a. thirty healthy aphids; b. uninfested tomato leaves; c. infested tomato with 30 healthy aphids; d. infested tomato leaves with 30 stressed aphids; e. thirty stressed aphids. C. sanguinea adults were strongly attracted to the odors of infested tomato leaves, but for the other odor sources, they did not visit active chambers more often than inactive chambers. C. sanguinea took less time to find active chambers with tomato leaves infested with healthy aphids than to find chambers with aphids or tomato leaves alone. These results suggest that C. sanguinea uses herbivore-induced volatile plant compounds as reliable indicators of herbivore infestation to locate prey.