The response of adult adzuki been borer <i>Ostrinia scapulalis</i> to light stimuli in a wind tunnel

Abstract

The attraction of nocturnal insects to light is a known phenomenon with unknown physiological mechanisms. Moths of the pyralid family are characterized by the most pronounced response to light, but the spectral preferences of these insects have not been studied. The adzuki been borers Ostrinia scapulalis, which live on dicotyledonous plants, are the ancestral form for the Asian and European corn borers, widespread pests of corn. Using a wind tunnel modified to deliver light stimuli, we tested the responses of males and females to light stimuli with wavelengths of 532, 440 and 365 nm at 2 lux, capable of stimulating photoreceptors of compound eyes (with maximum sensitivity of 352, 413, 480 and 530 nm) as well as simple ocelli, whose sensitivity had the main peak in ultraviolet and additional one in the green spectrum (360 and 520 nm). It turned out that ultraviolet was the most attractive stimulus. A small percentage of insects responded to green light, but showed a freezing reaction near the light source. The least attractive was blue light, which also caused freezes. Thus, the flight of O. scapulalis adults is induced by short-wavelength light, the response is more consistent with the sensitivity of the ocelli than the compound eyes; blue and green light leads to a masking effect.