Abstract
A pseudoplasmodium or slug of the cellular slime mold Dictyostelium discoideum sometimes shows positive thermotaxis or negative thermotaxis, this depending upon the relation between the temperature of amoeba growth to the late aggregation stage and the temperature of the migrating point. In this experiment, we investigated characteristics of ther-motaxis as a result of a tip exchange between positive thermotactic slugs and negative ones. Most of the tip-exchanged slugs showed negative thermotaxis. In phototaxis, it has been reported that the tip determines the migrating direction. In thermotaxis, however, this is not possible, and it is highly likely that the negatively thermotactic phenotype is dominant.
