Phototactic Behavior of<i>Coccinella septempunctata</i>L. (Coleoptera: Coccinellidae)

Abstract

We studied the behavioral response of the seven-spotted ladybird beetle, Coccinella septempunctata L., (Coleoptera, Coccinellinae) to various light wavelengths and intensities. Significant differences in the phototactic responses of beetles to 15 wavelengths of monochromatic light and white light were found. High phototactic response rates were observed to red light (649 nm) and ultraviolet (UV) light (340 nm), whereas low response rates were seen to green light, the species thus exhibiting a U-shaped response across the spectrum. The beetle also showed variation in response to 10 different illumination intensities. For a range of light intensities from 10 to 190 lux, beetles were generally more sensitive to ultraviolet light (340 nm) and red light (649 nm) than green light (510 nm) or white light. Differences in beetle response to various specific wavelengths were smallest in dim light (10 lux). The responses to ultraviolet and red light compared to those to green and white light were higher across all light intensity levels tested. The phototactic response to illumination intensity was correlated with light wavelengths, but there was no common trend across the three wavelengths of monochromatic light and white light. This experiment will help provide a scientific basis for the development of selected color traps used in insect pest management.