Walking behavior in a circular arena modified by pulsed light stimulation in Drosophila melanogaster w(1118) line

The Drosophila melanogaster white-eyed w(1118) line serves as a parental stock, allowing genetic recombination of any gene of interest along with a readily recognizable marker. w(1118) flies display behavioral susceptibility to environmental stimulation such as light. It is of great importance to characterize the behavioral performance of w(1118) flies because this would provide a baseline from which the effect of the gene of interest could be differentiated. Little work has been performed to characterize the walking behavior in adult w(1118) flies. Here we show that pulsed light stimulation increased the regularity of walking trajectories of w(1118) flies in circular arenas. We statistically modeled the distribution of distances to center and extracted the walking structures of w(1118) flies. Pulsed light stimulation redistributed the time proportions for individual walking structures. Specifically, pulsed light stimulation reduced the episodes of crossing over the central region of the arena. An addition of four genomic copies of mini-white, a common marker gene for eye color, mimicked the effect of pulsed light stimulation in reducing crossing in a circular arena. The reducing effect of mini-white was copy-number-dependent. These findings highlight the rhythmic light stimulation-evoked modifications of walking behavior in w(1118) flies and an unexpected behavioral consequence of mini-white in transgenic flies carrying w(1118) isogenic background.