Data from: Street lighting: sex-independent impacts on moth movement

1.Artificial lights have become an integral and welcome part of our urban and peri-urban environments. However, recent research has highlighted the potentially negative ecological consequences of ubiquitous artificial light. In particular, insects, especially moths, are expected to be negatively impacted by the presence of artificial lights. Previous research with light traps has shown a male-biased attraction to light in moths. 2.In this study, we sought to determine if street lights could limit moth dispersal and if there was any sex bias in attraction to light. More specifically, we aimed to determine sex specific attraction radii for moths to street lights. 3.We tested these hypotheses by collecting moths for two years at an experimental setup. To estimate the attraction radii we developed a Markov model and related it to the acquired data. 4.Utilizing multinomial statistics, we found that attraction rates to lights in the middle of the matrix were substantially lower than predicted by the null hypothesis of equal attraction level (0.44 times). With the Markov model, we estimated that a corner-light was 2.77 times more attractive than a wing-light with an equivalent attraction radius of c. 23m around each light. We found neither sexual differences in the attraction rate nor in the attraction radius of males and females. Since we captured three times more males than females, we conclude that sex ratios are representative of operational sex ratios or of different flight activities. 5.These results provide evidence for street lights to limit moth dispersal, and that they seem to act equally on male and female moths. Consequently, public lighting might divide a suitable landscape into many small habitats. Therefore, it is reasonable to assume i) that public lighting near hedges and bushes or field margins reduces the quality of these important habitat structures, and ii) that public lighting near important habitat structures but not interfering with local movement may affect moth movement between patches.