Analyzing the use of Humidity Cue in Navigation of Drosophila melanogaster

Abstract: Humidity is one of the main abiotic factor of ecosystems and affects animals behaviour, fitness and distribution. Due to their small size and inability to thermoregulate using metabolism, insects, such as the fruit fly Drosophila Melanogaster, are especially reliant on humidity. They are able to use humidity as a mean of navigation around their environment by using specialised hygroreceptor neurons. While these sensory neurons have been identified, hygrosensation and its transduction mechanism is poorly understood. We have built an experimental setup with adjustable temperature that delivers humidity stimuli, either humid or dry, to flies occupying different lanes in an arena. The idea is to test the effect of temperature on flies reaction to humidity to test hypothesis of transduction mechanism in hygrosensation, the ability to detect humidity. Here we show a clear response from humidity stimuli of D. melanogaster in a laboratory environment. The setup gives generally good results and has provided us with data supporting earlier evidence of fly behaviour. The data has been analysed using different features, but no non-trivial pattern of behaviour has been identified outside of a general rise of activity during dry stimuli. With this result we show that our experimental setup can be used for further experiments using more temperatures and control flies to find the means of transduction. We believe that the response of the flies is based on their preferred humidity level of 70 %, and that they are more active in the dry humidity in an effort to locate a more preferred level of humidity.