Effects of sleep deprivation on susceptibility to parasitic infection

We investigate the role of sleep deprivation on Drosophila nigrospiracula susceptibility to parasitic infections by the ectoparasitic mite, Macrocheles subbadius. We tested the hypothesis that sleep deprivation reduces behavioural resistance against mites, resulting in higher rates of infection among sleep deprived (SD) flies compared to non-sleep deprived flies, and that this is mediated by lower endurance (in negative geotaxis assays) among SD flies. We tested the impact of sleep deprivation on susceptibility to infection and climbing endurance in two age groups, flies 14 and 21 days post-eclosion. 

Methods
In the first experiment, flies from two age classes (14 and 21 days old) were subject to sleep deprivation during a 12 hr night period and then tested for susceptibility to infection. Control flies were left undisturbed for the night. For a given age class, five flies from each of treatment group were placed inside an infection chamber containing mites and left for 2 hours. Flies were then removed from the chamber and assessed for mite infection and number of mites. In a second experiment, flies were again subject to sleep deprivation or left undisturbed for a period of 12 hrs. Flies were then transferred to vials for negative geotaxis assays. Flies were placed inside a vial with a line located 5 cm from the base, once the fly climbed up to the line the vial was tapped to knock the fly down to the bottom. We measured climbing endurance as the number of times (cycles) and total duration a fly spent climbing.