Dainton (1954) showed that activity was stimulated by falling temperature below 22 °C in the slug Deroceras reticulatum (Agriolimax reticulatus) and that this response could account for the timing of the activity observed in the field. Runham & Hunter (1970) state that Lewis (1967) was unable to repeat this result on Arion ater. Experiments described here show that this slug does respond to falling temperatures below 22 °C by becoming active and that the time between the onset of the stimulus and the appearance of the activity is related to the rate of fall.
The apparatus consisted of a stirred water bath of uniform temperature which could be lowered at controlled rates by regulating the influx of iced water. Immersed in the bath were six air-filled glass chambers, the floor of each of which was lined with wet filter paper which served the dual purpose of saturating the air...
