Effects of mobility on daily attraction to light traps: comparison between lepidopteran and coleopteran communities

Abstract

Abstract. Light traps have been widely used for surveying insect community structure, but some biases are known to occur under certain meteorological conditions. In addition to weather factors, we raise the novel hypothesis that if the daily movement distance of focal insects is shorter than the effective range of the light trap, then the species richness and abundance of the daily captures will increase during the course of the night. This study examined the daily attraction patterns of Lepidoptera and Coleoptera to light traps and the factors affecting the attraction of these communities. Light traps were run for three consecutive nights in each month from April to October 2001 in a cool‐temperate forest in Japan. The species richness and abundance of Coleoptera increased during trap nights, whereas lepidopteran captures remained constant. Meteorological factors influenced the capture of both communities throughout the sampling season, but the daily increment in Coleoptera was not explained by the daily trends in weather conditions. We argue that the daily augmentation of Coleoptera capture rate results from the daily movement distance of Coleoptera being generally shorter than the effective and perceivable range of the light traps. These results suggest that consideration of the typical daily movement of a focal taxon is required when conducting biological monitoring using light trap sampling.