The effect of illumination with different light wavelengths on the orientation of Turkestan cockroach, Blatta lateralis (Walker, 1868) (Blattodea: Blattidae)

Abstract

In this study, the effect of illumination with different light wavelengths (red, green, yellow, blue, white and a dark control) on the orientation of the Turkestan cockroach, Blatta lateralis (Walker,1868) (Blattodea: Blattidae) was investigated. The study was conducted under laboratory conditions in 2019 at Bursa Uludag University. In orientation trials, adult cockroaches were exposed to three different light illuminances (25, 250 and 2500 lux). The trials were conducted in six- and two-arm choice arenas. In each trial, three replicates and 100 individuals were used. The data obtained show that the sensitivity to the illumination with different wavelengths may increase depending on light intensity. In particular, in the six-arm and two-arm trial, in the experiment where blue light of 2500 lux intensity was applied, the cockroach orientation was the lowest at 0.9% and 1.8%, respectively. In general, the highest orientation was against the dark (control) chamber in all trials. In addition, under all lux values, the orientation to red light was higher than with green, yellow, blue and white light. As a result of this study, it has been determined that blue light may have a repellent effect on cockroaches, and red light may be more attractive than other wavelengths. These studies can be useful in the development of an alternative method of control to replace chemicals used against cockroaches that would be harmless to human health and the environment.