Our laboratory previously described eRING (ethanol rapid iterative negative geotaxis) as an assay for measuring ethanol sensitivity in Drosophila (Figure S1) (Bhandari et al., 2009). Flies have a strong, innate negative geotaxis response (vertical climbing in response to being banged or rapped to the bottom of their container). eRING assays measure bang-induced climbing at one-minute intervals in the continuous presence of ethanol vapor. Flies are banged to the bottom of vials during each interval in eRING assays, right themselves and then climb toward the top of the vials. As the internal ethanol concentration of flies increases in eRING assays, flies become progressively impaired which is reflected as a time-dependent decrease in the distance climbed. Time-course data from eRING assays are used to derive a T50 (time of ethanol exposure causing a 50% reduction in climbing ability) as a standard measure of fly performance and ethanol sensitivity.
