Responses of different Drosophila species to temperature changes.

Temperature is a critical environmental variable that affects the distribution, survival and reproduction of most animals. Although temperature receptors have been identified in many animals, how these receptors respond to temperature is still unclear. Here, we describe an automated tracking method for studying the thermotactic behaviors of Drosophila larvae and adults. We built optimal experimental setups to capture behavioral recordings and analyzed them using free software, Fiji and TrackMate, which do not require programming knowledge. Then, we applied the adult thermotactic two-choice assay to examine the movement and temperature preferences of nine Drosophila species. The ability or inclination to move varied among these species and at different temperatures. Distinct species preferred various ranges of temperatures. Wild-type D. melanogaster flies avoided the warmer temperature in the warm avoidance assay and the cooler temperature in the cool avoidance assay. Conversely, D. bipectinata and D. yakuba did not avoid warm or cool temperatures in the respective assays, and D. biarmipes and D. mojavensis did not avoid the warm temperature in the warm avoidance assay. These results demonstrate that Drosophila species have different mobilities and temperature preferences, which will benefit further research in exploring molecular mechanisms of temperature responsiveness.