Speed was analyzed as described previously [4], with minor modifications: Briefly, assay plates were dried for two hours at 37°C with lids off on the day of the assay. Copper rings were melted into the surface of the plates, and two hours before the beginning of the assay, ice-cold 100% ethanol was added to plates to a final concentration in the agar of 0 mM or 400 mM. Age-matched first day adult animals were acclimated to the lack of food in the assay for a period of 30 minutes by moving them to unseeded dried plates. Ten worms of each test strain were moved into a copper ring on an assay plates and movies were recorded of their movement at 10 and 30 minutes of exposure. Only strains that were tested in the same assay on the same plates were compared to each other. Movies were made on an Olympus SZX-7 stereo microscope (magnification of 0.8x with a 0.5x objective to make a large enough field of view) using a Retiga 4000R camera (QImaging) and ImagePro Plus (6.2) (MediaCybernetics) software.
