Olfactory behavior of convergent lady beetles (Coleoptera: Coccinellidae) to alarm pheromone of green peach aphid (Hemiptera: Aphididae)

A previous investigation from our laboratory showed that the odor of live green peach aphids, Myzus persicae (Sulzer), highly attracts the convergent lady beetle, Hippodamia convergens Guerin-Meneville. In this study, we isolated the odor and identified it as (E)-beta -farnesene (an aphid alarm pheromone) using gas chromatography - mass spectrometry. The olfactory response of the convergent lady beetle to (E)-beta -farnesene was investigated using an eight-arm air-flow olfactometer and tracing the pathways of the lady beetles. The results clearly indicate that H. convergens can perceive and orient to (E)-beta -farnesene released by green peach aphids. These findings suggest that this: species of lady beetle has evolved a sensory system for detecting the green peach aphid alarm pheromone as a means of finding its prey.