Long-term exposure to extreme illumination regimes alters behavioral responses to light in the cockroach, Periplaneta americana L

The natural lighting conditions vary depending on latitude, niche and time of day; the animals are evolutionarily adapted to them. Artificial lighting along with global warming drive population ranges toward high latitudes, which creates fast-changing environments for the biota. The American cockroach is a synanthropic species with nocturnal lifestyle, rarely exposed to light. Three-month long exposure to constant light or constant darkness, in comparison with normal 12:12 day and night cycle, causes behavioral changes that is explained by two main factors: adaptation of visual system, and circadian rhythm disturbance. Freezing behavior, an indicator of circadian disturbances, appeared in groups kept under constant light regimes ant tested in the dark, as well as those subjected to experimental lighting with low intensity green light. Exposure to such light caused multidirectional behavioral changes in groups kept in different light regimes, reflecting their internal levels of arousal, stress, and light adaptation of their photoreceptor organs. Thus, altered lighting conditions impose significant challenges to different aspects of insect physiology and behavior.