The effects of nocturnal light on Odontotaenius disjunctus (Coleoptera: Passalidae)

Abstract

The effects of nocturnal light on the activity of burrowing insects have been rarely investigated. The goal of this study was to examine the effects of nocturnal light intensity on nocturnal activity of Bess beetles (Odontotaenius disjunctus). Individuals (n=18) were exposed to three artificial light treatments 25w (low light treatment), 50w (medium light treatment) or 75w (high light treatment) Eco terra night glo bulbs that were used to simulate the moonlight intensity of new moon, half moon, and full moon, respectively. During each light treatment the activities that were investigated and time spent total activity, walking, feeding and burrowing, resting and under the mulch. These activities of O. disjunctus were videotaped for four h under artificial lights on the three nights around each lunar phase. They were then compared to determine if time spent doing each activity was significantly affected by the artificial light. Total activity (walking, feeding and burrowing) differed significantly between the high light treatment and the medium light treatment, but this difference was not due to time spent walking, feeding or burrowing. That difference was due to time spend resting (above the mulch) and time spent under the mulch. These results suggest that nocturnal light intensity may affect the nocturnal activity of O. disjunctus. This may be due to the fact that beetles are infesting of wood on the full moon (Zurcher 2001), or creating family living structures or mating during the half moon. Tunnels and chambers were both found after the half moon supporting the idea that their mating may be affected by lunar phases, but more studies need to be done.