Lesser mealworm beetle displays negative phototaxis and conditional hydrotaxis

Arthropods use a variety of environmental cues to navigate between and locate hosts. In agricultural systems clarifying the relevant cues and their effects on arthropod behavior can inform management practices to reduce or inhibit the activity of arthropod pests. The lesser mealworm Alphitobius diaperinus (Panzer) is an ectoparasitic arthropod pest of broiler house chicken production, and while the patterns of movement and behavior of A. diaperinus are well documented, the specific environmental factors that govern these patterns are not known. We conducted behavioral assays testing the response of A. diaperinus adults and larvae to different wavelengths of light and to the presence of water. A. diaperinus displayed a significant repulsion from white and green light, and non-directional agitation in response to red and blue light, while larvae consistently sought shelter and displayed no behavioral change in response to light. Dehydrated adult beetles displayed a brief attraction to water while hydrated beetles displayed a repulsion to water. Dehydrated beetles maintained the attraction to water even when moisture sources were illuminated with white light. Taken together, these results indicate that A. diaperinus will hide from sources of light unless they are dehydrated and a source of water is accessible. Knowledge of the environmental cues that influence the behavior of A. diaperinus could be used to improve methods of trapping, monitoring, and controlling populations of A. diaperinus in experimental and commercial settings.