Response of the Pea Aphid Parasite Aphidius ervi Haliday (Hymenoptera: Aphidiidae) to Transmitted Light

The pea aphid parasite Aphidius ervi Haliday was tested in the laboratory for its response to transmitted light. When given a choice to respond to a series of two or three monochromatic lights in a series, parasites always chose that light nearest green in the spectrum. In dual choice tests, green (wavelength 514 nm) was six times more attractive than blue-green (424 nm), or two times more attractive than yellow-green (523 nm). Yellow-green was two times more attractive than blue-green. Response to green probably serves as a mechanism whereby flying parasites generally orient to vegetation where their aphid hosts would be located.